// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module parser

import v.scanner
import v.ast
import v.token
import v.pref
import v.util
import v.vet
import v.errors
import os
import hash.fnv1a

pub const builtin_functions = ['print', 'println', 'eprint', 'eprintln', 'isnil', 'panic', 'exit']

pub struct Parser {
	pref &pref.Preferences
mut:
	file_base         string       // "hello.v"
	file_name         string       // "/home/user/hello.v"
	file_name_dir     string       // "/home/user"
	unique_prefix     string       // a hash of p.file_name, used for making anon fn generation unique
	file_backend_mode ast.Language // .c for .c.v|.c.vv|.c.vsh files; .js for .js.v files, .amd64/.rv32/other arches for .amd64.v/.rv32.v/etc. files, .v otherwise.
	scanner           &scanner.Scanner
	comments_mode     scanner.CommentsMode = .skip_comments
	// see comment in parse_file
	tok                   token.Token
	prev_tok              token.Token
	peek_tok              token.Token
	table                 &ast.Table
	language              ast.Language
	fn_language           ast.Language // .c for `fn C.abcd()` declarations
	expr_level            int  // prevent too deep recursions for pathological programs
	inside_vlib_file      bool // true for all vlib/ files
	inside_test_file      bool // when inside _test.v or _test.vv file
	inside_if             bool
	inside_if_expr        bool
	inside_ct_if_expr     bool
	inside_or_expr        bool
	inside_for            bool
	inside_fn             bool // true even with implicit main
	inside_unsafe_fn      bool
	inside_str_interp     bool
	inside_array_lit      bool
	inside_in_array       bool
	inside_match          bool // to separate `match A { }` from `Struct{}`
	inside_select         bool // to allow `ch <- Struct{} {` inside `select`
	inside_match_case     bool // to separate `match_expr { }` from `Struct{}`
	inside_match_body     bool // to fix eval not used TODO
	inside_unsafe         bool
	inside_sum_type       bool // to prevent parsing inline sum type again
	inside_asm_template   bool
	inside_asm            bool
	inside_defer          bool
	inside_generic_params bool       // indicates if parsing between `<` and `>` of a method/function
	inside_receiver_param bool       // indicates if parsing the receiver parameter inside the first `(` and `)` of a method
	or_is_handled         bool       // ignore `or` in this expression
	builtin_mod           bool       // are we in the `builtin` module?
	mod                   string     // current module name
	is_manualfree         bool       // true when `[manualfree] module abc`, makes *all* fns in the current .v file, opt out of autofree
	has_globals           bool       // `[has_globals] module abc` - allow globals declarations, even without -enable-globals, in that single .v file __only__
	is_generated          bool       // `[generated] module abc` - turn off compiler notices for that single .v file __only__.
	attrs                 []ast.Attr // attributes before next decl stmt
	expr_mod              string     // for constructing full type names in parse_type()
	scope                 &ast.Scope
	imports               map[string]string // alias => mod_name
	ast_imports           []ast.Import      // mod_names
	used_imports          []string // alias
	auto_imports          []string // imports, the user does not need to specify
	imported_symbols      map[string]string
	is_amp                bool // for generating the right code for `&Foo{}`
	returns               bool
	is_stmt_ident         bool // true while the beginning of a statement is an ident/selector
	expecting_type        bool // `is Type`, expecting type
	errors                []errors.Error
	warnings              []errors.Warning
	notices               []errors.Notice
	vet_errors            []vet.Error
	cur_fn_name           string
	label_names           []string
	name_error            bool // indicates if the token is not a name or the name is on another line
	n_asm                 int  // controls assembly labels
	global_labels         []string
	comptime_if_cond      bool
	defer_vars            []ast.Ident
	should_abort          bool // when too many errors/warnings/notices are accumulated, should_abort becomes true, and the parser should stop
	codegen_text          string
}

// for tests
pub fn parse_stmt(text string, table &ast.Table, scope &ast.Scope) ast.Stmt {
	mut p := Parser{
		scanner: scanner.new_scanner(text, .skip_comments, &pref.Preferences{})
		inside_test_file: true
		table: table
		pref: &pref.Preferences{}
		scope: scope
	}
	p.init_parse_fns()
	util.timing_start('PARSE stmt')
	defer {
		util.timing_measure_cumulative('PARSE stmt')
	}
	p.read_first_token()
	return p.stmt(false)
}

pub fn parse_comptime(text string, table &ast.Table, pref &pref.Preferences, scope &ast.Scope) &ast.File {
	mut p := Parser{
		scanner: scanner.new_scanner(text, .skip_comments, pref)
		table: table
		pref: pref
		scope: scope
		errors: []errors.Error{}
		warnings: []errors.Warning{}
	}
	res := p.parse()
	unsafe { p.free_scanner() }
	return res
}

pub fn parse_text(text string, path string, table &ast.Table, comments_mode scanner.CommentsMode, pref &pref.Preferences) &ast.File {
	mut p := Parser{
		scanner: scanner.new_scanner(text, comments_mode, pref)
		comments_mode: comments_mode
		table: table
		pref: pref
		scope: &ast.Scope{
			start_pos: 0
			parent: table.global_scope
		}
		errors: []errors.Error{}
		warnings: []errors.Warning{}
	}
	p.set_path(path)
	res := p.parse()
	unsafe { p.free_scanner() }
	return res
}

[unsafe]
pub fn (mut p Parser) free() {
	unsafe { p.free_scanner() }
}

[unsafe]
pub fn (mut p Parser) free_scanner() {
	unsafe {
		if p.scanner != 0 {
			p.scanner.free()
			p.scanner = &scanner.Scanner(0)
		}
	}
}

pub fn (mut p Parser) set_path(path string) {
	p.file_name = path
	p.file_base = os.base(path)
	p.file_name_dir = os.dir(path)
	if p.file_name_dir.contains('vlib') {
		p.inside_vlib_file = true
	}
	hash := fnv1a.sum64_string(path)
	p.unique_prefix = hash.hex_full()
	if p.file_base.ends_with('_test.v') || p.file_base.ends_with('_test.vv') {
		p.inside_test_file = true
	}
	before_dot_v := path.all_before_last('.v') // also works for .vv and .vsh
	language := before_dot_v.all_after_last('.')
	language_with_underscore := before_dot_v.all_after_last('_')
	if language == before_dot_v && language_with_underscore == before_dot_v {
		p.file_backend_mode = .v
		return
	}
	actual_language := if language == before_dot_v { language_with_underscore } else { language }
	match actual_language {
		'c' {
			p.file_backend_mode = .c
		}
		'js' {
			p.file_backend_mode = .js
		}
		else {
			arch := pref.arch_from_string(actual_language) or { pref.Arch._auto }
			p.file_backend_mode = ast.pref_arch_to_table_language(arch)
			if arch == ._auto {
				p.file_backend_mode = .v
			}
		}
	}
}

pub fn parse_file(path string, table &ast.Table, comments_mode scanner.CommentsMode, pref &pref.Preferences) &ast.File {
	// NB: when comments_mode == .toplevel_comments,
	// the parser gives feedback to the scanner about toplevel statements, so that the scanner can skip
	// all the tricky inner comments. This is needed because we do not have a good general solution
	// for handling them, and should be removed when we do (the general solution is also needed for vfmt)
	mut p := Parser{
		scanner: scanner.new_scanner_file(path, comments_mode, pref)
		comments_mode: comments_mode
		table: table
		pref: pref
		scope: &ast.Scope{
			start_pos: 0
			parent: table.global_scope
		}
		errors: []errors.Error{}
		warnings: []errors.Warning{}
	}
	p.set_path(path)
	res := p.parse()
	unsafe { p.free_scanner() }
	return res
}

pub fn parse_vet_file(path string, table_ &ast.Table, pref &pref.Preferences) (&ast.File, []vet.Error) {
	global_scope := &ast.Scope{
		parent: 0
	}
	mut p := Parser{
		scanner: scanner.new_scanner_file(path, .parse_comments, pref)
		comments_mode: .parse_comments
		table: table_
		pref: pref
		scope: &ast.Scope{
			start_pos: 0
			parent: global_scope
		}
		errors: []errors.Error{}
		warnings: []errors.Warning{}
	}
	p.set_path(path)
	if p.scanner.text.contains_any_substr(['\n  ', ' \n']) {
		source_lines := os.read_lines(path) or { []string{} }
		for lnumber, line in source_lines {
			if line.starts_with('  ') {
				p.vet_error('Looks like you are using spaces for indentation.', lnumber,
					.vfmt, .space_indent)
			}
			if line.ends_with(' ') {
				p.vet_error('Looks like you have trailing whitespace.', lnumber, .unknown,
					.trailing_space)
			}
		}
	}
	p.vet_errors << p.scanner.vet_errors
	file := p.parse()
	unsafe { p.free_scanner() }
	return file, p.vet_errors
}

pub fn (mut p Parser) parse() &ast.File {
	util.timing_start('PARSE')
	defer {
		util.timing_measure_cumulative('PARSE')
	}
	// comments_mode: comments_mode
	p.init_parse_fns()
	p.read_first_token()
	mut stmts := []ast.Stmt{}
	for p.tok.kind == .comment {
		stmts << p.comment_stmt()
	}
	// module
	module_decl := p.module_decl()
	if module_decl.is_skipped {
		stmts.insert(0, ast.Stmt(module_decl))
	} else {
		stmts << module_decl
	}
	// imports
	for {
		if p.tok.kind == .key_import {
			stmts << p.import_stmt()
			continue
		}
		if p.tok.kind == .comment {
			stmts << p.comment_stmt()
			continue
		}
		break
	}
	for {
		if p.tok.kind == .eof {
			p.check_unused_imports()
			break
		}
		stmt := p.top_stmt()
		// clear the attributes after each statement
		if !(stmt is ast.ExprStmt && (stmt as ast.ExprStmt).expr is ast.Comment) {
			p.attrs = []
		}
		stmts << stmt
		if p.should_abort {
			break
		}
	}
	p.scope.end_pos = p.tok.pos

	mut errors := p.errors
	mut warnings := p.warnings
	mut notices := p.notices

	if p.pref.check_only {
		errors << p.scanner.errors
		warnings << p.scanner.warnings
		notices << p.scanner.notices
	}

	// codegen
	if p.codegen_text.len > 0 && !p.pref.is_fmt {
		ptext := 'module ' + p.mod.all_after_last('.') + p.codegen_text
		codegen_file := parse_text(ptext, p.file_name, p.table, p.comments_mode, p.pref)
		stmts << codegen_file.stmts
	}

	return &ast.File{
		path: p.file_name
		path_base: p.file_base
		is_test: p.inside_test_file
		is_generated: p.is_generated
		nr_lines: p.scanner.line_nr
		nr_bytes: p.scanner.text.len
		mod: module_decl
		imports: p.ast_imports
		imported_symbols: p.imported_symbols
		auto_imports: p.auto_imports
		stmts: stmts
		scope: p.scope
		global_scope: p.table.global_scope
		errors: errors
		warnings: warnings
		notices: notices
		global_labels: p.global_labels
	}
}

/*
struct Queue {
mut:
	idx              int
	mu               &sync.Mutex
	mu2              &sync.Mutex
	paths            []string
	table            &ast.Table
	parsed_ast_files []&ast.File
	pref             &pref.Preferences
	global_scope     &ast.Scope
}

fn (mut q Queue) run() {
	for {
		q.mu.lock()
		idx := q.idx
		if idx >= q.paths.len {
			q.mu.unlock()
			return
		}
		q.idx++
		q.mu.unlock()
		println('run(idx=$idx)')
		path := q.paths[idx]
		file := parse_file(path, q.table, .skip_comments, q.pref, q.global_scope)
		q.mu2.lock()
		q.parsed_ast_files << file
		q.mu2.unlock()
		println('run done(idx=$idx)')
	}
}
*/
pub fn parse_files(paths []string, table &ast.Table, pref &pref.Preferences) []&ast.File {
	mut timers := util.new_timers(should_print: false, label: 'parse_files: $paths')
	$if time_parsing ? {
		timers.should_print = true
	}
	$if macos {
		/*
		if !pref.no_parallel && paths[0].contains('/array.v') {
			println('\n\n\nparse_files() nr_files=$paths.len')
			println(paths)
			nr_cpus := runtime.nr_cpus()
			mut q := &Queue{
				paths: paths
				table: table
				pref: pref
				global_scope: global_scope
				mu: sync.new_mutex()
				mu2: sync.new_mutex()
			}
			for _ in 0 .. nr_cpus - 1 {
				go q.run()
			}
			time.sleep(time.second)
			println('all done')
			return q.parsed_ast_files
		}
		*/
	}
	mut files := []&ast.File{cap: paths.len}
	for path in paths {
		timers.start('parse_file $path')
		files << parse_file(path, table, .skip_comments, pref)
		timers.show('parse_file $path')
	}
	return files
}

// codegen allows you to generate V code, so that it can be parsed,
// checked, markused, cgen-ed etc further, just like user's V code.
pub fn (mut p Parser) codegen(code string) {
	$if debug_codegen ? {
		eprintln('parser.codegen:\n $code')
	}
	p.codegen_text += '\n' + code
}

pub fn (mut p Parser) init_parse_fns() {
	// p.prefix_parse_fns = make(100, 100, sizeof(PrefixParseFn))
	// p.prefix_parse_fns[token.Kind.name] = parse_name
}

pub fn (mut p Parser) read_first_token() {
	// need to call next() 2 times to get peek token and current token
	p.next()
	p.next()
}

[inline]
pub fn (p &Parser) peek_token(n int) token.Token {
	return p.scanner.peek_token(n - 2)
}

pub fn (mut p Parser) open_scope() {
	p.scope = &ast.Scope{
		parent: p.scope
		start_pos: p.tok.pos
	}
}

pub fn (mut p Parser) close_scope() {
	// p.scope.end_pos = p.tok.pos
	// NOTE: since this is usually called after `p.parse_block()`
	// ie. when `prev_tok` is rcbr `}` we most likely want `prev_tok`
	// we could do the following, but probably not needed in 99% of cases:
	// `end_pos = if p.prev_tok.kind == .rcbr { p.prev_tok.pos } else { p.tok.pos }`
	p.scope.end_pos = p.prev_tok.pos
	p.scope.parent.children << p.scope
	p.scope = p.scope.parent
}

pub fn (mut p Parser) parse_block() []ast.Stmt {
	p.open_scope()
	stmts := p.parse_block_no_scope(false)
	p.close_scope()
	return stmts
}

pub fn (mut p Parser) parse_block_no_scope(is_top_level bool) []ast.Stmt {
	p.check(.lcbr)
	mut stmts := []ast.Stmt{cap: 20}
	if p.tok.kind != .rcbr {
		mut count := 0
		for p.tok.kind !in [.eof, .rcbr] {
			stmts << p.stmt(is_top_level)
			count++
			if count % 100000 == 0 {
				eprintln('parsed $count statements so far from fn $p.cur_fn_name ...')
			}
			if count > 1000000 {
				p.error_with_pos('parsed over $count statements from fn $p.cur_fn_name, the parser is probably stuck',
					p.tok.position())
				return []
			}
		}
	}
	if is_top_level {
		p.top_level_statement_end()
	}
	p.check(.rcbr)
	return stmts
}

fn (mut p Parser) next() {
	p.prev_tok = p.tok
	p.tok = p.peek_tok
	p.peek_tok = p.scanner.scan()
}

fn (mut p Parser) check(expected token.Kind) {
	p.name_error = false
	if _likely_(p.tok.kind == expected) {
		p.next()
	} else {
		if expected == .name {
			p.name_error = true
		}
		mut s := expected.str()
		// quote keywords, punctuation, operators
		if token.is_key(s) || (s.len > 0 && !s[0].is_letter()) {
			s = '`$s`'
		}
		p.error('unexpected $p.tok, expecting $s')
	}
}

// JS functions can have multiple dots in their name:
// JS.foo.bar.and.a.lot.more.dots()
fn (mut p Parser) check_js_name() string {
	mut name := ''
	for p.peek_tok.kind == .dot {
		name += '${p.tok.lit}.'
		p.next() // .name
		p.next() // .dot
	}
	// last .name
	name += p.tok.lit
	p.next()
	return name
}

fn (mut p Parser) check_name() string {
	name := p.tok.lit
	if p.peek_tok.kind == .dot && name in p.imports {
		p.register_used_import(name)
	}
	p.check(.name)
	return name
}

[if trace_parser ?]
fn (p &Parser) trace_parser(label string) {
	eprintln('parsing: ${p.file_name:-30}|tok.pos: ${p.tok.position().line_str():-39}|tok.kind: ${p.tok.kind:-10}|tok.lit: ${p.tok.lit:-10}|$label')
}

pub fn (mut p Parser) top_stmt() ast.Stmt {
	p.trace_parser('top_stmt')
	for {
		match p.tok.kind {
			.key_pub {
				match p.peek_tok.kind {
					.key_const {
						return p.const_decl()
					}
					.key_fn {
						return p.fn_decl()
					}
					.key_struct, .key_union {
						return p.struct_decl()
					}
					.key_interface {
						return p.interface_decl()
					}
					.key_enum {
						return p.enum_decl()
					}
					.key_type {
						return p.type_decl()
					}
					else {
						return p.error('wrong pub keyword usage')
					}
				}
			}
			.lsbr {
				// attrs are stored in `p.attrs`
				p.attributes()
				continue
			}
			.key_asm {
				return p.asm_stmt(true)
			}
			.key_interface {
				return p.interface_decl()
			}
			.key_import {
				p.error_with_pos('`import x` can only be declared at the beginning of the file',
					p.tok.position())
				return p.import_stmt()
			}
			.key_global {
				return p.global_decl()
			}
			.key_const {
				return p.const_decl()
			}
			.key_fn {
				return p.fn_decl()
			}
			.key_struct {
				return p.struct_decl()
			}
			.dollar {
				if_expr := p.if_expr(true)
				return ast.ExprStmt{
					expr: if_expr
					pos: if_expr.pos
				}
			}
			.hash {
				return p.hash()
			}
			.key_type {
				return p.type_decl()
			}
			.key_enum {
				return p.enum_decl()
			}
			.key_union {
				return p.struct_decl()
			}
			.comment {
				return p.comment_stmt()
			}
			else {
				p.inside_fn = true
				if p.pref.is_script && !p.pref.is_test {
					p.open_scope()
					mut stmts := []ast.Stmt{}
					for p.tok.kind != .eof {
						stmts << p.stmt(false)
					}
					p.close_scope()
					return ast.FnDecl{
						name: 'main.main'
						mod: 'main'
						is_main: true
						stmts: stmts
						file: p.file_name
						return_type: ast.void_type
						scope: p.scope
						label_names: p.label_names
					}
				} else if p.pref.is_fmt {
					return p.stmt(false)
				} else {
					return p.error('bad top level statement ' + p.tok.str())
				}
			}
		}
		if p.should_abort {
			break
		}
	}
	// TODO remove dummy return statement
	// the compiler complains if it's not there
	return ast.empty_stmt()
}

// TODO [if vfmt]
pub fn (mut p Parser) check_comment() ast.Comment {
	if p.tok.kind == .comment {
		return p.comment()
	}
	return ast.Comment{}
}

pub fn (mut p Parser) comment() ast.Comment {
	mut pos := p.tok.position()
	text := p.tok.lit
	num_newlines := text.count('\n')
	is_multi := num_newlines > 0
	is_inline := text.len + 4 == p.tok.len // 4: `/` `*` `*` `/`
	pos.last_line = pos.line_nr + num_newlines
	p.next()
	// Filter out false positive space indent vet errors inside comments
	if p.vet_errors.len > 0 && is_multi {
		p.vet_errors = p.vet_errors.filter(it.typ != .space_indent
			|| it.pos.line_nr - 1 > pos.last_line || it.pos.line_nr - 1 <= pos.line_nr)
	}
	return ast.Comment{
		text: text
		is_multi: is_multi
		is_inline: is_inline
		pos: pos
	}
}

pub fn (mut p Parser) comment_stmt() ast.ExprStmt {
	comment := p.comment()
	return ast.ExprStmt{
		expr: comment
		pos: comment.pos
	}
}

[params]
struct EatCommentsConfig {
	same_line bool // Only eat comments on the same line as the previous token
	follow_up bool // Comments directly below the previous token as long as there is no empty line
}

pub fn (mut p Parser) eat_comments(cfg EatCommentsConfig) []ast.Comment {
	mut line := p.prev_tok.line_nr
	mut comments := []ast.Comment{}
	for {
		if p.tok.kind != .comment || (cfg.same_line && p.tok.line_nr > line)
			|| (cfg.follow_up && (p.tok.line_nr > line + 1 || p.tok.lit.contains('\n'))) {
			break
		}
		comments << p.comment()
		if cfg.follow_up {
			line = p.prev_tok.line_nr
		}
	}
	return comments
}

pub fn (mut p Parser) stmt(is_top_level bool) ast.Stmt {
	p.trace_parser('stmt($is_top_level)')
	p.is_stmt_ident = p.tok.kind == .name
	match p.tok.kind {
		.lcbr {
			mut pos := p.tok.position()
			stmts := p.parse_block()
			pos.last_line = p.prev_tok.line_nr
			return ast.Block{
				stmts: stmts
				pos: pos
			}
		}
		.key_assert {
			p.next()
			mut pos := p.tok.position()
			expr := p.expr(0)
			pos.update_last_line(p.prev_tok.line_nr)
			return ast.AssertStmt{
				expr: expr
				pos: pos.extend(p.tok.position())
				is_used: p.inside_test_file || !p.pref.is_prod
			}
		}
		.key_for {
			return p.for_stmt()
		}
		.name {
			if p.tok.lit == 'sql' && p.peek_tok.kind == .name {
				return p.sql_stmt()
			}
			if p.peek_tok.kind == .colon {
				// `label:`
				spos := p.tok.position()
				name := p.check_name()
				if name in p.label_names {
					p.error_with_pos('duplicate label `$name`', spos)
				}
				p.label_names << name
				p.next()
				if p.tok.kind == .key_for {
					for_pos := p.tok.position()
					mut stmt := p.stmt(is_top_level)
					match mut stmt {
						ast.ForStmt {
							stmt.label = name
							return stmt
						}
						ast.ForInStmt {
							stmt.label = name
							return stmt
						}
						ast.ForCStmt {
							stmt.label = name
							return stmt
						}
						else {
							p.error_with_pos('unknown kind of For statement', for_pos)
						}
					}
				}
				return ast.GotoLabel{
					name: name
					pos: spos.extend(p.tok.position())
				}
			} else if p.peek_tok.kind == .name {
				return p.error_with_pos('unexpected name `$p.tok.lit`', p.tok.position())
			} else if !p.inside_if_expr && !p.inside_match_body && !p.inside_or_expr
				&& p.peek_tok.kind in [.rcbr, .eof] && !p.mark_var_as_used(p.tok.lit) {
				return p.error_with_pos('`$p.tok.lit` evaluated but not used', p.tok.position())
			}
			return p.parse_multi_expr(is_top_level)
		}
		.comment {
			return p.comment_stmt()
		}
		.key_return {
			if p.inside_defer {
				return p.error_with_pos('`return` not allowed inside `defer` block', p.tok.position())
			} else {
				return p.return_stmt()
			}
		}
		.dollar {
			match p.peek_tok.kind {
				.key_if {
					mut pos := p.tok.position()
					expr := p.if_expr(true)
					pos.update_last_line(p.prev_tok.line_nr)
					return ast.ExprStmt{
						expr: expr
						pos: pos
					}
				}
				.key_for {
					return p.comptime_for()
				}
				.name {
					mut pos := p.tok.position()
					expr := p.comptime_call()
					pos.update_last_line(p.prev_tok.line_nr)
					return ast.ExprStmt{
						expr: expr
						pos: pos
					}
				}
				else {
					return p.error_with_pos('unexpected \$', p.tok.position())
				}
			}
		}
		.key_continue, .key_break {
			tok := p.tok
			line := p.tok.line_nr
			p.next()
			mut label := ''
			if p.tok.line_nr == line && p.tok.kind == .name {
				label = p.check_name()
			}
			return ast.BranchStmt{
				kind: tok.kind
				label: label
				pos: tok.position()
			}
		}
		.key_unsafe {
			return p.unsafe_stmt()
		}
		.hash {
			return p.hash()
		}
		.key_defer {
			if p.inside_defer {
				return p.error_with_pos('`defer` blocks cannot be nested', p.tok.position())
			} else {
				p.next()
				spos := p.tok.position()
				p.inside_defer = true
				p.defer_vars = []ast.Ident{}
				stmts := p.parse_block()
				p.inside_defer = false
				return ast.DeferStmt{
					stmts: stmts
					defer_vars: p.defer_vars.clone()
					pos: spos.extend_with_last_line(p.tok.position(), p.prev_tok.line_nr)
				}
			}
		}
		.key_go {
			go_expr := p.go_expr()
			return ast.ExprStmt{
				expr: go_expr
				pos: go_expr.pos
			}
		}
		.key_goto {
			p.next()
			spos := p.tok.position()
			name := p.check_name()
			return ast.GotoStmt{
				name: name
				pos: spos
			}
		}
		.key_const {
			return p.error_with_pos('const can only be defined at the top level (outside of functions)',
				p.tok.position())
		}
		.key_asm {
			return p.asm_stmt(false)
		}
		// literals, 'if', etc. in here
		else {
			return p.parse_multi_expr(is_top_level)
		}
	}
}

fn (mut p Parser) asm_stmt(is_top_level bool) ast.AsmStmt {
	p.inside_asm = true
	p.inside_asm_template = true
	defer {
		p.inside_asm = false
		p.inside_asm_template = false
	}
	p.n_asm = 0
	if is_top_level {
		p.top_level_statement_start()
	}
	mut backup_scope := p.scope

	pos := p.tok.position()

	p.check(.key_asm)
	mut arch := pref.arch_from_string(p.tok.lit) or { pref.Arch._auto }
	mut is_volatile := false
	mut is_goto := false
	if p.tok.kind == .key_volatile {
		arch = pref.arch_from_string(p.peek_tok.lit) or { pref.Arch._auto }
		is_volatile = true
		p.next()
	} else if p.tok.kind == .key_goto {
		arch = pref.arch_from_string(p.peek_tok.lit) or { pref.Arch._auto }
		is_goto = true
		p.next()
	}
	if arch == ._auto && !p.pref.is_fmt {
		if p.tok.lit == '' {
			p.error('missing assembly architecture. Try i386, amd64 or arm64.')
		}
		p.error('unknown assembly architecture')
	}
	if p.tok.kind != .name {
		p.error('must specify assembly architecture')
	} else {
		p.next()
	}

	p.check_for_impure_v(ast.pref_arch_to_table_language(arch), p.prev_tok.position())

	p.check(.lcbr)
	p.scope = &ast.Scope{
		parent: 0 // you shouldn't be able to reference other variables in assembly blocks
		detached_from_parent: true
		start_pos: p.tok.pos
		objects: ast.all_registers(mut p.table, arch) //
	}

	mut local_labels := []string{}
	// riscv: https://github.com/jameslzhu/riscv-card/blob/master/riscv-card.pdf
	// x86: https://www.felixcloutier.com/x86/
	// arm: https://developer.arm.com/documentation/dui0068/b/arm-instruction-reference
	mut templates := []ast.AsmTemplate{}
	for p.tok.kind !in [.semicolon, .rcbr] {
		template_pos := p.tok.position()
		mut name := ''
		if p.tok.kind == .name && arch == .amd64 && p.tok.lit in ['rex', 'vex', 'xop'] {
			name += p.tok.lit
			p.next()
			for p.tok.kind == .dot {
				p.next()
				name += '.' + p.tok.lit
				p.check(.name)
			}
			name += ' '
		}
		is_directive := p.tok.kind == .dot
		if is_directive {
			p.next()
		}
		if p.tok.kind in [.key_in, .key_lock, .key_orelse] { // `in`, `lock`, `or` are v keywords that are also x86/arm/riscv instructions.
			name += p.tok.kind.str()
			p.next()
		} else if p.tok.kind == .number {
			name += p.tok.lit
			p.next()
		} else {
			name += p.tok.lit
			p.check(.name)
		}
		// dots are part of instructions for some riscv extensions
		if arch in [.rv32, .rv64] {
			for p.tok.kind == .dot {
				name += '.'
				p.next()
				name += p.tok.lit
				p.check(.name)
			}
		}
		mut is_label := false

		mut args := []ast.AsmArg{}
		if p.tok.line_nr == p.prev_tok.line_nr {
			args_loop: for {
				if p.prev_tok.position().line_nr < p.tok.position().line_nr {
					break
				}
				mut segment := ''
				if p.tok.kind == .name && p.peek_tok.kind == .colon {
					segment = p.tok.lit
					p.next()
					p.next()
				}
				match p.tok.kind {
					.name {
						args << p.reg_or_alias()
					}
					.number {
						number_lit := p.parse_number_literal()
						match number_lit {
							ast.FloatLiteral {
								args << ast.FloatLiteral{
									...number_lit
								}
							}
							ast.IntegerLiteral {
								if is_directive {
									args << ast.AsmDisp{
										val: number_lit.val
										pos: number_lit.pos
									}
								} else {
									args << ast.IntegerLiteral{
										...number_lit
									}
								}
							}
							else {
								verror('p.parse_number_literal() invalid output: `$number_lit`')
							}
						}
					}
					.chartoken {
						args << ast.CharLiteral{
							val: p.tok.lit
							pos: p.tok.position()
						}
						p.next()
					}
					.colon {
						is_label = true
						p.next()
						local_labels << name
						break
					}
					.lsbr {
						mut addressing := p.asm_addressing()
						addressing.segment = segment
						args << addressing
					}
					.rcbr {
						break
					}
					.semicolon {
						break
					}
					else {
						p.error('invalid token in assembly block')
					}
				}
				if p.tok.kind == .comma {
					p.next()
				} else {
					break
				}
			}
			// if p.prev_tok.position().line_nr < p.tok.position().line_nr {
			// 	break
			// }
		}
		mut comments := []ast.Comment{}
		for p.tok.kind == .comment {
			comments << p.comment()
		}
		if is_directive && name in ['globl', 'global'] {
			for arg in args {
				p.global_labels << (arg as ast.AsmAlias).name
			}
		}
		templates << ast.AsmTemplate{
			name: name
			args: args
			comments: comments
			is_label: is_label
			is_directive: is_directive
			pos: template_pos.extend(p.tok.position())
		}
	}
	mut scope := p.scope
	p.scope = backup_scope
	p.inside_asm_template = false
	mut output, mut input, mut clobbered, mut global_labels := []ast.AsmIO{}, []ast.AsmIO{}, []ast.AsmClobbered{}, []string{}
	if !is_top_level {
		if p.tok.kind == .semicolon {
			output = p.asm_ios(true)
			if p.tok.kind == .semicolon {
				input = p.asm_ios(false)
			}
			if p.tok.kind == .semicolon {
				// because p.reg_or_alias() requires the scope with registers to recognize registers.
				backup_scope = p.scope
				p.scope = scope
				p.next()
				for p.tok.kind == .name {
					reg := ast.AsmRegister{
						name: p.tok.lit
						typ: 0
						size: -1
					}
					p.next()

					mut comments := []ast.Comment{}
					for p.tok.kind == .comment {
						comments << p.comment()
					}
					clobbered << ast.AsmClobbered{
						reg: reg
						comments: comments
					}

					if p.tok.kind in [.rcbr, .semicolon] {
						break
					}
				}

				if is_goto && p.tok.kind == .semicolon {
					p.next()
					for p.tok.kind == .name {
						global_labels << p.tok.lit
						p.next()
					}
				}
			}
		}
	} else if p.tok.kind == .semicolon {
		p.error('extended assembly is not allowed as a top level statement')
	}
	p.scope = backup_scope
	p.check(.rcbr)
	if is_top_level {
		p.top_level_statement_end()
	}
	scope.end_pos = p.prev_tok.pos

	return ast.AsmStmt{
		arch: arch
		is_goto: is_goto
		is_volatile: is_volatile
		templates: templates
		output: output
		input: input
		clobbered: clobbered
		pos: pos.extend(p.prev_tok.position())
		is_basic: is_top_level || output.len + input.len + clobbered.len == 0
		scope: scope
		global_labels: global_labels
		local_labels: local_labels
	}
}

fn (mut p Parser) reg_or_alias() ast.AsmArg {
	p.check(.name)
	if p.prev_tok.lit in p.scope.objects {
		x := unsafe { p.scope.objects[p.prev_tok.lit] }
		if x is ast.AsmRegister {
			return ast.AsmArg(x as ast.AsmRegister)
		} else {
			verror('non-register ast.ScopeObject found in scope')
			return ast.AsmDisp{} // should not be reached
		}
	} else if p.prev_tok.len >= 2 && p.prev_tok.lit[0] in [`b`, `f`]
		&& p.prev_tok.lit[1..].bytes().all(it.is_digit()) {
		return ast.AsmDisp{
			val: p.prev_tok.lit[1..] + p.prev_tok.lit[0].ascii_str()
		}
	} else {
		return ast.AsmAlias{
			name: p.prev_tok.lit
			pos: p.prev_tok.position()
		}
	}
}

// fn (mut p Parser) asm_addressing() ast.AsmAddressing {
// 	pos := p.tok.position()
// 	p.check(.lsbr)
// 	unknown_addressing_mode := 'unknown addressing mode. supported ones are [displacement],	[base], [base + displacement] [index ∗ scale + displacement], [base + index ∗ scale + displacement], [base + index + displacement] [rip + displacement]'
// 	mut mode := ast.AddressingMode.invalid
// 	if p.peek_tok.kind == .rsbr {
// 		if p.tok.kind == .name {
// 			mode = .base
// 		} else if p.tok.kind == .number {
// 			mode = .displacement
// 		} else {
// 			p.error(unknown_addressing_mode)
// 		}
// 	} else if p.peek_tok.kind == .mul {
// 		mode = .index_times_scale_plus_displacement
// 	} else if p.tok.lit == 'rip' {
// 		mode = .rip_plus_displacement
// 	} else if p.peek_tok3.kind == .mul {
// 		mode = .base_plus_index_times_scale_plus_displacement
// 	} else if p.peek_tok.kind == .plus && p.peek_tok3.kind == .rsbr {
// 		mode = .base_plus_displacement
// 	} else if p.peek_tok.kind == .plus && p.peek_tok3.kind == .plus {
// 		mode = .base_plus_index_plus_displacement
// 	} else {
// 		p.error(unknown_addressing_mode)
// 	}
// 	mut displacement, mut base, mut index, mut scale := u32(0), ast.AsmArg{}, ast.AsmArg{}, -1

// 	match mode {
// 		.base {
// 			base = p.reg_or_alias()
// 		}
// 		.displacement {
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.base_plus_displacement {
// 			base = p.reg_or_alias()
// 			p.check(.plus)
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.index_times_scale_plus_displacement {
// 			index = p.reg_or_alias()
// 			p.check(.mul)
// 			scale = p.tok.lit.int()
// 			p.check(.number)
// 			p.check(.plus)
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.base_plus_index_times_scale_plus_displacement {
// 			base = p.reg_or_alias()
// 			p.check(.plus)
// 			index = p.reg_or_alias()
// 			p.check(.mul)
// 			scale = p.tok.lit.int()
// 			p.check(.number)
// 			p.check(.plus)
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.rip_plus_displacement {
// 			base = p.reg_or_alias()
// 			p.check(.plus)
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.base_plus_index_plus_displacement {
// 			base = p.reg_or_alias()
// 			p.check(.plus)
// 			index = p.reg_or_alias()
// 			p.check(.plus)
// 			displacement = p.tok.lit.u32()
// 			p.check(.number)
// 		}
// 		.invalid {} // there was already an error above
// 	}

// 	p.check(.rsbr)
// 	return ast.AsmAddressing{
// 		base: base
// 		displacement: displacement
// 		index: index
// 		scale: scale
// 		mode: mode
// 		pos: pos.extend(p.prev_tok.position())
// 	}
// }

fn (mut p Parser) asm_addressing() ast.AsmAddressing {
	pos := p.tok.position()
	p.check(.lsbr)
	unknown_addressing_mode := 'unknown addressing mode. supported ones are [displacement],	[base], [base + displacement], [index ∗ scale + displacement], [base + index ∗ scale + displacement], [base + index + displacement], [rip + displacement]'
	// this mess used to look much cleaner before the removal of peek_tok2/3, see above code for cleaner version
	if p.peek_tok.kind == .rsbr { // [displacement] or [base]
		if p.tok.kind == .name {
			base := p.reg_or_alias()
			p.check(.rsbr)
			return ast.AsmAddressing{
				mode: .base
				base: base
				pos: pos.extend(p.prev_tok.position())
			}
		} else if p.tok.kind == .number {
			displacement := if p.tok.kind == .name {
				p.reg_or_alias()
			} else {
				x := ast.AsmArg(ast.AsmDisp{
					val: p.tok.lit
					pos: p.tok.position()
				})
				p.check(.number)
				x
			}
			p.check(.rsbr)
			return ast.AsmAddressing{
				mode: .displacement
				displacement: displacement
				pos: pos.extend(p.prev_tok.position())
			}
		} else {
			p.error(unknown_addressing_mode)
		}
	}
	if p.peek_tok.kind == .plus && p.tok.kind == .name { // [base + displacement], [base + index ∗ scale + displacement], [base + index + displacement] or [rip + displacement]
		if p.tok.lit == 'rip' {
			rip := p.reg_or_alias()
			p.next()

			displacement := if p.tok.kind == .name {
				p.reg_or_alias()
			} else {
				x := ast.AsmArg(ast.AsmDisp{
					val: p.tok.lit
					pos: p.tok.position()
				})
				p.check(.number)
				x
			}
			p.check(.rsbr)
			return ast.AsmAddressing{
				mode: .rip_plus_displacement
				base: rip
				displacement: displacement
				pos: pos.extend(p.prev_tok.position())
			}
		}
		base := p.reg_or_alias()
		p.next()
		if p.peek_tok.kind == .rsbr {
			if p.tok.kind == .number {
				displacement := if p.tok.kind == .name {
					p.reg_or_alias()
				} else {
					x := ast.AsmArg(ast.AsmDisp{
						val: p.tok.lit
						pos: p.tok.position()
					})
					p.check(.number)
					x
				}
				p.check(.rsbr)
				return ast.AsmAddressing{
					mode: .base_plus_displacement
					base: base
					displacement: displacement
					pos: pos.extend(p.prev_tok.position())
				}
			} else {
				p.error(unknown_addressing_mode)
			}
		}
		index := p.reg_or_alias()
		if p.tok.kind == .mul {
			p.next()
			scale := p.tok.lit.int()
			p.check(.number)
			p.check(.plus)
			displacement := if p.tok.kind == .name {
				p.reg_or_alias()
			} else {
				x := ast.AsmArg(ast.AsmDisp{
					val: p.tok.lit
					pos: p.tok.position()
				})
				p.check(.number)
				x
			}
			p.check(.rsbr)
			return ast.AsmAddressing{
				mode: .base_plus_index_times_scale_plus_displacement
				base: base
				index: index
				scale: scale
				displacement: displacement
				pos: pos.extend(p.prev_tok.position())
			}
		} else if p.tok.kind == .plus {
			p.next()
			displacement := if p.tok.kind == .name {
				p.reg_or_alias()
			} else {
				x := ast.AsmArg(ast.AsmDisp{
					val: p.tok.lit
					pos: p.tok.position()
				})
				p.check(.number)
				x
			}
			p.check(.rsbr)
			return ast.AsmAddressing{
				mode: .base_plus_index_plus_displacement
				base: base
				index: index
				displacement: displacement
				pos: pos.extend(p.prev_tok.position())
			}
		}
	}
	if p.peek_tok.kind == .mul { // [index ∗ scale + displacement]
		index := p.reg_or_alias()
		p.next()
		scale := p.tok.lit.int()
		p.check(.number)
		p.check(.plus)
		displacement := if p.tok.kind == .name {
			p.reg_or_alias()
		} else {
			x := ast.AsmArg(ast.AsmDisp{
				val: p.tok.lit
				pos: p.tok.position()
			})
			p.check(.number)
			x
		}
		p.check(.rsbr)
		return ast.AsmAddressing{
			mode: .index_times_scale_plus_displacement
			index: index
			scale: scale
			displacement: displacement
			pos: pos.extend(p.prev_tok.position())
		}
	}
	p.error(unknown_addressing_mode)
	return ast.AsmAddressing{}
}

fn (mut p Parser) asm_ios(output bool) []ast.AsmIO {
	mut res := []ast.AsmIO{}
	p.check(.semicolon)
	if p.tok.kind in [.rcbr, .semicolon] {
		return []
	}
	for {
		pos := p.tok.position()

		mut constraint := ''
		if p.tok.kind == .lpar {
			constraint = if output { '+r' } else { 'r' } // default constraint, though vfmt fmts to `+r` and `r`
		} else {
			constraint += match p.tok.kind {
				.assign {
					'='
				}
				.plus {
					'+'
				}
				.mod {
					'%'
				}
				.amp {
					'&'
				}
				else {
					''
				}
			}
			if constraint != '' {
				p.next()
			}
			constraint += p.tok.lit
			if p.tok.kind == .at {
				p.next()
			} else {
				p.check(.name)
			}
		}
		mut expr := p.expr(0)
		if mut expr is ast.ParExpr {
			expr = expr.expr
		} else {
			p.error('asm in/output must be enclosed in brackets')
		}
		mut alias := ''
		if p.tok.kind == .key_as {
			p.next()
			alias = p.tok.lit
			p.check(.name)
		} else if mut expr is ast.Ident {
			alias = expr.name
		}
		// for constraints like `a`, no alias is needed, it is reffered to as rcx
		mut comments := []ast.Comment{}
		for p.tok.kind == .comment {
			comments << p.comment()
		}

		res << ast.AsmIO{
			alias: alias
			constraint: constraint
			expr: expr
			comments: comments
			pos: pos.extend(p.prev_tok.position())
		}
		p.n_asm++
		if p.tok.kind in [.semicolon, .rcbr] {
			break
		}
	}
	return res
}

fn (mut p Parser) expr_list() ([]ast.Expr, []ast.Comment) {
	mut exprs := []ast.Expr{}
	mut comments := []ast.Comment{}
	for {
		expr := p.expr(0)
		if expr is ast.Comment {
			comments << expr
		} else {
			exprs << expr
			if p.tok.kind != .comma {
				break
			}
			p.next()
		}
	}
	return exprs, comments
}

fn (mut p Parser) is_attributes() bool {
	if p.tok.kind != .lsbr {
		return false
	}
	mut i := 0
	for {
		tok := p.peek_token(i)
		if tok.kind == .eof || tok.line_nr != p.tok.line_nr {
			return false
		}
		if tok.kind == .rsbr {
			break
		}
		i++
	}
	peek_rsbr_tok := p.peek_token(i + 1)
	if peek_rsbr_tok.line_nr == p.tok.line_nr && peek_rsbr_tok.kind != .rcbr {
		return false
	}
	return true
}

// when is_top_stmt is true attrs are added to p.attrs
fn (mut p Parser) attributes() {
	p.check(.lsbr)
	mut has_ctdefine := false
	for p.tok.kind != .rsbr {
		start_pos := p.tok.position()
		attr := p.parse_attr()
		if p.attrs.contains(attr.name) && attr.name != 'wasm_export' {
			p.error_with_pos('duplicate attribute `$attr.name`', start_pos.extend(p.prev_tok.position()))
			return
		}
		if attr.kind == .comptime_define {
			if has_ctdefine {
				p.error_with_pos('only one `[if flag]` may be applied at a time `$attr.name`',
					start_pos.extend(p.prev_tok.position()))
				return
			} else {
				has_ctdefine = true
			}
		}
		p.attrs << attr
		if p.tok.kind != .semicolon {
			if p.tok.kind == .rsbr {
				p.next()
				break
			}
			p.error('unexpected $p.tok, expecting `;`')
			return
		}
		p.next()
	}
	if p.attrs.len == 0 {
		p.error_with_pos('attributes cannot be empty', p.prev_tok.position().extend(p.tok.position()))
		return
	}
}

fn (mut p Parser) parse_attr() ast.Attr {
	mut kind := ast.AttrKind.plain
	apos := p.prev_tok.position()
	if p.tok.kind == .key_unsafe {
		p.next()
		return ast.Attr{
			name: 'unsafe'
			kind: kind
			pos: apos.extend(p.tok.position())
		}
	}
	mut name := ''
	mut has_arg := false
	mut arg := ''
	mut comptime_cond := ast.empty_expr()
	mut comptime_cond_opt := false
	if p.tok.kind == .key_if {
		kind = .comptime_define
		p.next()
		p.comptime_if_cond = true
		p.inside_if_expr = true
		p.inside_ct_if_expr = true
		comptime_cond = p.expr(0)
		p.comptime_if_cond = false
		p.inside_if_expr = false
		p.inside_ct_if_expr = false
		if comptime_cond is ast.PostfixExpr {
			comptime_cond_opt = true
		}
		name = comptime_cond.str()
	} else if p.tok.kind == .string {
		name = p.tok.lit
		kind = .string
		p.next()
	} else {
		name = p.check_name()
		// support dot prefix `module.name: arg`
		if p.tok.kind == .dot {
			p.next()
			name += '.'
			name += p.check_name()
		}
		if p.tok.kind == .colon {
			has_arg = true
			p.next()
			if p.tok.kind == .name { // `name: arg`
				kind = .plain
				arg = p.check_name()
			} else if p.tok.kind == .number { // `name: 123`
				kind = .number
				arg = p.tok.lit
				p.next()
			} else if p.tok.kind == .string { // `name: 'arg'`
				kind = .string
				arg = p.tok.lit
				p.next()
			} else if p.tok.kind == .key_true || p.tok.kind == .key_false { // `name: true`
				kind = .bool
				arg = p.tok.kind.str()
				p.next()
			} else {
				p.error('unexpected $p.tok, an argument is expected after `:`')
			}
		}
	}
	return ast.Attr{
		name: name
		has_arg: has_arg
		arg: arg
		kind: kind
		ct_expr: comptime_cond
		ct_opt: comptime_cond_opt
		pos: apos.extend(p.tok.position())
	}
}

pub fn (mut p Parser) language_not_allowed_error(language ast.Language, pos token.Position) {
	upcase_language := language.str().to_upper()
	p.error_with_pos('$upcase_language code is not allowed in .${p.file_backend_mode}.v files, please move it to a .${language}.v file',
		pos)
}

pub fn (mut p Parser) language_not_allowed_warning(language ast.Language, pos token.Position) {
	upcase_language := language.str().to_upper()
	p.warn_with_pos('$upcase_language code will not be allowed in pure .v files, please move it to a .${language}.v file instead',
		pos)
}

pub fn (mut p Parser) check_for_impure_v(language ast.Language, pos token.Position) {
	if language == .v {
		// pure V code is always allowed everywhere
		return
	} else {
		match p.file_backend_mode {
			.c {
				if language != .c {
					p.language_not_allowed_error(language, pos)
					return
				}
			}
			.js {
				if language != .js {
					p.language_not_allowed_error(language, pos)
					return
				}
			}
			else {}
		}
	}
	if !p.pref.warn_impure_v {
		// the stricter mode is not ON yet => allow everything for now
		return
	}
	if p.file_backend_mode != language {
		if p.file_backend_mode == .v {
			p.language_not_allowed_warning(language, pos)
			return
		}
	}
}

pub fn (mut p Parser) error(s string) ast.NodeError {
	return p.error_with_pos(s, p.tok.position())
}

pub fn (mut p Parser) warn(s string) {
	p.warn_with_pos(s, p.tok.position())
}

pub fn (mut p Parser) note(s string) {
	p.note_with_pos(s, p.tok.position())
}

pub fn (mut p Parser) error_with_pos(s string, pos token.Position) ast.NodeError {
	if p.pref.fatal_errors {
		exit(1)
	}
	mut kind := 'error:'
	if p.pref.output_mode == .stdout && !p.pref.check_only {
		if p.pref.is_verbose {
			print_backtrace()
			kind = 'parser error:'
		}
		ferror := util.formatted_error(kind, s, p.file_name, pos)
		eprintln(ferror)
		exit(1)
	} else {
		p.errors << errors.Error{
			file_path: p.file_name
			pos: pos
			reporter: .parser
			message: s
		}

		// To avoid getting stuck after an error, the parser
		// will proceed to the next token.
		if p.pref.check_only {
			p.next()
		}
	}
	if p.pref.output_mode == .silent {
		// Normally, parser errors mean that the parser exits immediately, so there can be only 1 parser error.
		// In the silent mode however, the parser continues to run, even though it would have stopped. Some
		// of the parser logic does not expect that, and may loop forever.
		// The p.next() here is needed, so the parser is more robust, and *always* advances, even in the -silent mode.
		p.next()
	}
	return ast.NodeError{
		idx: p.errors.len - 1
		pos: pos
	}
}

pub fn (mut p Parser) error_with_error(error errors.Error) {
	if p.pref.fatal_errors {
		exit(1)
	}
	mut kind := 'error:'
	if p.pref.output_mode == .stdout && !p.pref.check_only {
		if p.pref.is_verbose {
			print_backtrace()
			kind = 'parser error:'
		}
		ferror := util.formatted_error(kind, error.message, error.file_path, error.pos)
		eprintln(ferror)
		exit(1)
	} else {
		if p.pref.message_limit >= 0 && p.errors.len >= p.pref.message_limit {
			p.should_abort = true
			return
		}
		p.errors << error
	}
	if p.pref.output_mode == .silent {
		// Normally, parser errors mean that the parser exits immediately, so there can be only 1 parser error.
		// In the silent mode however, the parser continues to run, even though it would have stopped. Some
		// of the parser logic does not expect that, and may loop forever.
		// The p.next() here is needed, so the parser is more robust, and *always* advances, even in the -silent mode.
		p.next()
	}
}

pub fn (mut p Parser) warn_with_pos(s string, pos token.Position) {
	if p.pref.warns_are_errors {
		p.error_with_pos(s, pos)
		return
	}
	if p.pref.skip_warnings {
		return
	}
	if p.pref.output_mode == .stdout && !p.pref.check_only {
		ferror := util.formatted_error('warning:', s, p.file_name, pos)
		eprintln(ferror)
	} else {
		if p.pref.message_limit >= 0 && p.warnings.len >= p.pref.message_limit {
			p.should_abort = true
			return
		}
		p.warnings << errors.Warning{
			file_path: p.file_name
			pos: pos
			reporter: .parser
			message: s
		}
	}
}

pub fn (mut p Parser) note_with_pos(s string, pos token.Position) {
	if p.pref.skip_warnings {
		return
	}
	if p.is_generated {
		return
	}
	if p.pref.output_mode == .stdout && !p.pref.check_only {
		ferror := util.formatted_error('notice:', s, p.file_name, pos)
		eprintln(ferror)
	} else {
		p.notices << errors.Notice{
			file_path: p.file_name
			pos: pos
			reporter: .parser
			message: s
		}
	}
}

pub fn (mut p Parser) vet_error(msg string, line int, fix vet.FixKind, typ vet.ErrorType) {
	pos := token.Position{
		line_nr: line + 1
	}
	p.vet_errors << vet.Error{
		message: msg
		file_path: p.scanner.file_path
		pos: pos
		kind: .error
		fix: fix
		typ: typ
	}
}

fn (mut p Parser) parse_multi_expr(is_top_level bool) ast.Stmt {
	// in here might be 1) multi-expr 2) multi-assign
	// 1, a, c ... }       // multi-expression
	// a, mut b ... :=/=   // multi-assign
	// collect things upto hard boundaries
	tok := p.tok
	mut pos := tok.position()

	mut defer_vars := p.defer_vars
	p.defer_vars = []ast.Ident{}

	left, left_comments := p.expr_list()

	if !(p.inside_defer && p.tok.kind == .decl_assign) {
		defer_vars << p.defer_vars
	}

	p.defer_vars = defer_vars

	left0 := left[0]
	if tok.kind == .key_mut && p.tok.kind != .decl_assign {
		return p.error('expecting `:=` (e.g. `mut x :=`)')
	}
	// TODO remove translated
	if p.tok.kind in [.assign, .decl_assign] || p.tok.kind.is_assign() {
		return p.partial_assign_stmt(left, left_comments)
	} else if !p.pref.translated && !p.pref.is_fmt
		&& tok.kind !in [.key_if, .key_match, .key_lock, .key_rlock, .key_select] {
		for node in left {
			if (is_top_level || p.tok.kind != .rcbr) && node !is ast.CallExpr
				&& node !is ast.PostfixExpr && node !is ast.ComptimeCall
				&& node !is ast.SelectorExpr && node !is ast.DumpExpr {
				is_complex_infix_expr := node is ast.InfixExpr
					&& (node as ast.InfixExpr).op in [.left_shift, .right_shift, .unsigned_right_shift, .arrow]
				if !is_complex_infix_expr {
					return p.error_with_pos('expression evaluated but not used', node.position())
				}
			}
		}
	}
	pos.update_last_line(p.prev_tok.line_nr)
	if left.len == 1 {
		return ast.ExprStmt{
			expr: left0
			pos: left0.position()
			comments: left_comments
			is_expr: p.inside_for
		}
	}
	return ast.ExprStmt{
		expr: ast.ConcatExpr{
			vals: left
			pos: tok.position()
		}
		pos: pos
		comments: left_comments
	}
}

pub fn (mut p Parser) parse_ident(language ast.Language) ast.Ident {
	// p.warn('name ')
	is_shared := p.tok.kind == .key_shared
	is_atomic := p.tok.kind == .key_atomic
	if is_shared {
		p.register_auto_import('sync')
	}
	mut_pos := p.tok.position()
	is_mut := p.tok.kind == .key_mut || is_shared || is_atomic
	if is_mut {
		p.next()
	}
	is_static := p.tok.kind == .key_static
	if is_static {
		p.next()
	}
	is_volatile := p.tok.kind == .key_volatile
	if is_volatile {
		p.next()
	}
	if p.tok.kind != .name {
		p.error('unexpected token `$p.tok.lit`')
		return ast.Ident{
			scope: p.scope
		}
	}
	pos := p.tok.position()
	mut name := p.check_name()
	if name == '_' {
		return ast.Ident{
			tok_kind: p.tok.kind
			name: '_'
			comptime: p.comptime_if_cond
			kind: .blank_ident
			pos: pos
			info: ast.IdentVar{
				is_mut: false
				is_static: false
				is_volatile: false
			}
			scope: p.scope
		}
	}
	if p.inside_match_body && name == 'it' {
		// p.warn('it')
	}
	if p.expr_mod.len > 0 {
		name = '${p.expr_mod}.$name'
	}
	return ast.Ident{
		tok_kind: p.tok.kind
		kind: .unresolved
		name: name
		comptime: p.comptime_if_cond
		language: language
		mod: p.mod
		pos: pos
		is_mut: is_mut
		mut_pos: mut_pos
		info: ast.IdentVar{
			is_mut: is_mut
			is_static: is_static
			is_volatile: is_volatile
			share: ast.sharetype_from_flags(is_shared, is_atomic)
		}
		scope: p.scope
	}
}

fn (p &Parser) is_typename(t token.Token) bool {
	return t.kind == .name && (t.lit[0].is_capital() || p.table.known_type(t.lit))
}

// heuristics to detect `func<T>()` from `var < expr`
// 1. `f<[]` is generic(e.g. `f<[]int>`) because `var < []` is invalid
// 2. `f<map[` is generic(e.g. `f<map[string]string>)
// 3. `f<foo>` is generic because `v1 < foo > v2` is invalid syntax
// 4. `f<foo<bar` is generic when bar is not generic T (f<foo<T>(), in contrast, is not generic!)
// 5. `f<Foo,` is generic when Foo is typename.
//	   otherwise it is not generic because it may be multi-value (e.g. `return f < foo, 0`).
// 6. `f<mod.Foo>` is same as case 3
// 7. `f<mod.Foo,` is same as case 5
// 8. if there is a &, ignore the & and see if it is a type
// 9. otherwise, it's not generic
// see also test_generic_detection in vlib/v/tests/generics_test.v
fn (p &Parser) is_generic_call() bool {
	lit0_is_capital := p.tok.kind != .eof && p.tok.lit.len > 0 && p.tok.lit[0].is_capital()
	if lit0_is_capital || p.peek_tok.kind != .lt {
		return false
	}
	mut tok2 := p.peek_token(2)
	mut tok3 := p.peek_token(3)
	mut tok4 := p.peek_token(4)
	mut tok5 := p.peek_token(5)
	mut kind2, mut kind3, mut kind4, mut kind5 := tok2.kind, tok3.kind, tok4.kind, tok5.kind
	if kind2 == .amp { // if there is a & in front, shift everything left
		tok2 = tok3
		kind2 = kind3
		tok3 = tok4
		kind3 = kind4
		tok4 = tok5
		kind4 = kind5
		tok5 = p.peek_token(6)
		kind5 = tok5.kind
	}

	if kind2 == .lsbr {
		// case 1
		return tok3.kind == .rsbr
	}

	if kind2 == .name {
		if tok2.lit == 'map' && kind3 == .lsbr {
			// case 2
			return true
		}
		return match kind3 {
			.gt { true } // case 3
			.lt { !(tok4.lit.len == 1 && tok4.lit[0].is_capital()) } // case 4
			.comma { p.is_typename(tok2) } // case 5
			// case 6 and 7
			.dot { kind4 == .name && (kind5 == .gt || (kind5 == .comma && p.is_typename(tok4))) }
			else { false }
		}
	}
	return false
}

const valid_tokens_inside_types = [token.Kind.lsbr, .rsbr, .name, .dot, .comma, .key_fn, .lt]

fn (mut p Parser) is_generic_cast() bool {
	if !ast.type_can_start_with_token(p.tok) {
		return false
	}
	mut i := 0
	mut level := 0
	mut lt_count := 0
	for {
		i++
		tok := p.peek_token(i)

		if tok.kind == .lt {
			lt_count++
			level++
		} else if tok.kind == .gt {
			level--
		}
		if lt_count > 0 && level == 0 {
			break
		}

		if i > 20 || tok.kind !in parser.valid_tokens_inside_types {
			return false
		}
	}
	next_tok := p.peek_token(i + 1)
	// `next_tok` is the token following the closing `>` of the generic type: MyType<int>{
	//                                                                                   ^
	// if `next_tok` is a left paren, then the full expression looks something like
	// `Foo<string>(` or `Foo<mod.Type>(`, which are valid type casts - return true
	if next_tok.kind == .lpar {
		return true
	}
	// any other token is not a valid generic cast, however
	return false
}

pub fn (mut p Parser) name_expr() ast.Expr {
	prev_tok_kind := p.prev_tok.kind
	mut node := ast.empty_expr()
	if p.expecting_type {
		p.expecting_type = false
		// get type position before moving to next
		type_pos := p.tok.position()
		typ := p.parse_type()
		return ast.TypeNode{
			typ: typ
			pos: type_pos
		}
	}
	mut language := ast.Language.v
	if p.tok.lit == 'C' {
		language = ast.Language.c
		p.check_for_impure_v(language, p.tok.position())
	} else if p.tok.lit == 'JS' {
		language = ast.Language.js
		p.check_for_impure_v(language, p.tok.position())
	}
	mut mod := ''
	// p.warn('resetting')
	p.expr_mod = ''
	// `map[string]int` initialization
	if p.tok.lit == 'map' && p.peek_tok.kind == .lsbr {
		map_type := p.parse_map_type()
		if p.tok.kind == .lcbr {
			p.next()
			if p.tok.kind == .rcbr {
				p.next()
			} else {
				if p.pref.is_fmt {
					map_init := p.map_init()
					p.check(.rcbr)
					return map_init
				}
				p.error('`}` expected; explicit `map` initialization does not support parameters')
			}
		}
		return ast.MapInit{
			typ: map_type
			pos: p.prev_tok.position()
		}
	}
	// `chan typ{...}`
	if p.tok.lit == 'chan' {
		first_pos := p.tok.position()
		mut last_pos := first_pos
		chan_type := p.parse_chan_type()
		mut has_cap := false
		mut cap_expr := ast.empty_expr()
		p.check(.lcbr)
		if p.tok.kind == .rcbr {
			last_pos = p.tok.position()
			p.next()
		} else {
			key := p.check_name()
			p.check(.colon)
			match key {
				'cap' {
					has_cap = true
					cap_expr = p.expr(0)
				}
				'len', 'init' {
					return p.error('`$key` cannot be initialized for `chan`. Did you mean `cap`?')
				}
				else {
					return p.error('wrong field `$key`, expecting `cap`')
				}
			}
			last_pos = p.tok.position()
			p.check(.rcbr)
		}
		return ast.ChanInit{
			pos: first_pos.extend(last_pos)
			has_cap: has_cap
			cap_expr: cap_expr
			typ: chan_type
		}
	}
	// Raw string (`s := r'hello \n ')
	if p.peek_tok.kind == .string && !p.inside_str_interp && p.peek_token(2).kind != .colon {
		if p.tok.lit in ['r', 'c', 'js'] && p.tok.kind == .name {
			return p.string_expr()
		} else {
			// don't allow any other string prefix except `r`, `js` and `c`
			return p.error('only `c`, `r`, `js` are recognized string prefixes, but you tried to use `$p.tok.lit`')
		}
	}
	// don't allow r`byte` and c`byte`
	if p.tok.lit in ['r', 'c'] && p.peek_tok.kind == .chartoken {
		opt := if p.tok.lit == 'r' { '`r` (raw string)' } else { '`c` (c string)' }
		return p.error('cannot use $opt with `byte` and `rune`')
	}
	// Make sure that the var is not marked as used in assignments: `x = 1`, `x += 2` etc
	// but only when it's actually used (e.g. `println(x)`)
	known_var := if p.peek_tok.kind.is_assign() {
		p.scope.known_var(p.tok.lit)
	} else {
		p.mark_var_as_used(p.tok.lit)
	}
	// Handle modules
	mut is_mod_cast := false
	if p.peek_tok.kind == .dot && !known_var && (language != .v || p.known_import(p.tok.lit)
		|| p.mod.all_after_last('.') == p.tok.lit) {
		// p.tok.lit has been recognized as a module
		if language == .c {
			mod = 'C'
		} else if language == .js {
			mod = 'JS'
		} else {
			if p.tok.lit in p.imports {
				// mark the imported module as used
				p.register_used_import(p.tok.lit)
				if p.peek_tok.kind == .dot && p.peek_token(2).kind != .eof
					&& p.peek_token(2).lit.len > 0 && p.peek_token(2).lit[0].is_capital() {
					is_mod_cast = true
				} else if p.peek_tok.kind == .dot && p.peek_token(2).kind != .eof
					&& p.peek_token(2).lit.len == 0 {
					// incomplete module selector must be handled by dot_expr instead
					ident := p.parse_ident(language)
					node = ident
					if p.inside_defer {
						if !p.defer_vars.any(it.name == ident.name && it.mod == ident.mod)
							&& ident.name != 'err' {
							p.defer_vars << ident
						}
					}
					return node
				}
			}
			// prepend the full import
			mod = p.imports[p.tok.lit]
		}
		p.next()
		p.check(.dot)
		p.expr_mod = mod
	}
	lit0_is_capital := if p.tok.kind != .eof && p.tok.lit.len > 0 {
		p.tok.lit[0].is_capital()
	} else {
		false
	}
	is_optional := p.tok.kind == .question
	is_generic_call := p.is_generic_call()
	is_generic_cast := p.is_generic_cast()
	// p.warn('name expr  $p.tok.lit $p.peek_tok.str()')
	same_line := p.tok.line_nr == p.peek_tok.line_nr
	// `(` must be on same line as name token otherwise it's a ParExpr
	if !same_line && p.peek_tok.kind == .lpar {
		ident := p.parse_ident(language)
		node = ident
		if p.inside_defer {
			if !p.defer_vars.any(it.name == ident.name && it.mod == ident.mod)
				&& ident.name != 'err' {
				p.defer_vars << ident
			}
		}
	} else if p.peek_tok.kind == .lpar || is_generic_call || is_generic_cast
		|| (is_optional && p.peek_token(2).kind == .lpar) {
		// foo(), foo<int>() or type() cast
		mut name := if is_optional { p.peek_tok.lit } else { p.tok.lit }
		if mod.len > 0 {
			name = '${mod}.$name'
		}
		name_w_mod := p.prepend_mod(name)
		// type cast. TODO: finish
		// if name in ast.builtin_type_names_to_idx {
		if (!known_var && (name in p.table.type_idxs || name_w_mod in p.table.type_idxs)
			&& name !in ['C.stat', 'C.sigaction']) || is_mod_cast || is_generic_cast
			|| (language == .v && name.len > 0 && name[0].is_capital()) {
			// MainLetter(x) is *always* a cast, as long as it is not `C.`
			// TODO handle C.stat()
			start_pos := p.tok.position()
			mut to_typ := p.parse_type()
			// this prevents inner casts to also have an `&`
			// example: &Foo(malloc(int(num)))
			// without the next line int would result in int*
			p.is_amp = false
			p.check(.lpar)
			mut expr := ast.empty_expr()
			mut arg := ast.empty_expr()
			mut has_arg := false
			expr = p.expr(0)
			// TODO, string(b, len)
			if p.tok.kind == .comma && to_typ.idx() == ast.string_type_idx {
				p.next()
				arg = p.expr(0) // len
				has_arg = true
			}
			end_pos := p.tok.position()
			p.check(.rpar)
			node = ast.CastExpr{
				typ: to_typ
				typname: p.table.sym(to_typ).name
				expr: expr
				arg: arg
				has_arg: has_arg
				pos: start_pos.extend(end_pos)
			}
			p.expr_mod = ''
			return node
		} else {
			// fn call
			if is_optional {
				p.error_with_pos('unexpected $p.prev_tok', p.prev_tok.position())
			}
			node = p.call_expr(language, mod)
		}
	} else if (p.peek_tok.kind == .lcbr || (p.peek_tok.kind == .lt && lit0_is_capital))
		&& (!p.inside_match || (p.inside_select && prev_tok_kind == .arrow && lit0_is_capital))
		&& !p.inside_match_case && (!p.inside_if || p.inside_select)
		&& (!p.inside_for || p.inside_select) && !known_var { // && (p.tok.lit[0].is_capital() || p.builtin_mod) {
		// map.v has struct literal: map{field: expr}
		if p.peek_tok.kind == .lcbr && !(p.builtin_mod
			&& p.file_base in ['map.v', 'map_d_gcboehm_opt.v']) && p.tok.lit == 'map' {
			// map{key_expr: val_expr}
			p.check(.name)
			p.check(.lcbr)
			map_init := p.map_init()
			p.check(.rcbr)
			return map_init
		}
		return p.struct_init(false) // short_syntax: false
	} else if p.peek_tok.kind == .lcbr && p.inside_if && lit0_is_capital && !known_var
		&& language == .v {
		// if a == Foo{} {...}
		return p.struct_init(false)
	} else if p.peek_tok.kind == .dot && (lit0_is_capital && !known_var && language == .v) {
		// T.name
		if p.is_generic_name() {
			pos := p.tok.position()
			name := p.check_name()
			p.check(.dot)
			field := p.check_name()
			fkind := match field {
				'name' { ast.GenericKindField.name }
				'typ' { ast.GenericKindField.typ }
				else { ast.GenericKindField.unknown }
			}
			pos.extend(p.tok.position())
			return ast.SelectorExpr{
				expr: ast.Ident{
					name: name
					scope: p.scope
				}
				field_name: field
				gkind_field: fkind
				pos: pos
				scope: p.scope
			}
		}
		// `Color.green`
		mut enum_name := p.check_name()
		enum_name_pos := p.prev_tok.position()
		if mod != '' {
			enum_name = mod + '.' + enum_name
		} else {
			enum_name = p.imported_symbols[enum_name] or { p.prepend_mod(enum_name) }
		}
		p.check(.dot)
		val := p.check_name()
		p.expr_mod = ''
		return ast.EnumVal{
			enum_name: enum_name
			val: val
			pos: enum_name_pos.extend(p.prev_tok.position())
			mod: mod
		}
	} else if language == .js && p.peek_tok.kind == .dot && p.peek_token(2).kind == .name {
		// JS. function call with more than 1 dot
		node = p.call_expr(language, mod)
	} else {
		if p.inside_in_array && ((lit0_is_capital && !known_var && language == .v)
			|| (p.peek_tok.kind == .dot && p.peek_token(2).lit.len > 0
			&& p.peek_token(2).lit[0].is_capital())
			|| p.table.find_type_idx(p.mod + '.' + p.tok.lit) > 0) {
			type_pos := p.tok.position()
			typ := p.parse_type()
			return ast.TypeNode{
				typ: typ
				pos: type_pos
			}
		}

		ident := p.parse_ident(language)
		node = ident
		if p.inside_defer {
			if !p.defer_vars.any(it.name == ident.name && it.mod == ident.mod)
				&& ident.name != 'err' {
				p.defer_vars << ident
			}
		}
	}
	p.expr_mod = ''
	return node
}

fn (mut p Parser) index_expr(left ast.Expr, is_gated bool) ast.IndexExpr {
	// left == `a` in `a[0]`
	start_pos := p.tok.position()
	p.next() // [
	mut has_low := true
	if p.tok.kind == .dotdot {
		has_low = false
		// [..end]
		p.next()
		mut high := ast.empty_expr()
		mut has_high := false
		if p.tok.kind != .rsbr {
			high = p.expr(0)
			has_high = true
		}
		pos := start_pos.extend(p.tok.position())
		p.check(.rsbr)
		return ast.IndexExpr{
			left: left
			pos: pos
			index: ast.RangeExpr{
				low: ast.empty_expr()
				high: high
				has_high: has_high
				pos: pos
				is_gated: is_gated
			}
			is_gated: is_gated
		}
	}
	expr := p.expr(0) // `[expr]` or  `[expr..`
	mut has_high := false
	if p.tok.kind == .dotdot {
		// [start..end] or [start..]
		p.next()
		mut high := ast.empty_expr()
		if p.tok.kind != .rsbr {
			has_high = true
			high = p.expr(0)
		}
		pos := start_pos.extend(p.tok.position())
		p.check(.rsbr)
		return ast.IndexExpr{
			left: left
			pos: pos
			index: ast.RangeExpr{
				low: expr
				high: high
				has_high: has_high
				has_low: has_low
				pos: pos
				is_gated: is_gated
			}
			is_gated: is_gated
		}
	}
	// [expr]
	pos := start_pos.extend(p.tok.position())
	p.check(.rsbr)
	mut or_kind := ast.OrKind.absent
	mut or_stmts := []ast.Stmt{}
	mut or_pos := token.Position{}
	if !p.or_is_handled {
		// a[i] or { ... }
		if p.tok.kind == .key_orelse {
			was_inside_or_expr := p.inside_or_expr
			p.inside_or_expr = true
			or_pos = p.tok.position()
			p.next()
			p.open_scope()
			or_stmts = p.parse_block_no_scope(false)
			or_pos = or_pos.extend(p.prev_tok.position())
			p.close_scope()
			p.inside_or_expr = was_inside_or_expr
			return ast.IndexExpr{
				left: left
				index: expr
				pos: pos
				or_expr: ast.OrExpr{
					kind: .block
					stmts: or_stmts
					pos: or_pos
				}
				is_gated: is_gated
			}
		}
		// `a[i] ?`
		if p.tok.kind == .question {
			or_pos = p.tok.position()
			or_kind = .propagate
			p.next()
		}
	}
	return ast.IndexExpr{
		left: left
		index: expr
		pos: pos
		or_expr: ast.OrExpr{
			kind: or_kind
			stmts: or_stmts
			pos: or_pos
		}
		is_gated: is_gated
	}
}

fn (mut p Parser) scope_register_it() {
	p.scope.register(ast.Var{
		name: 'it'
		pos: p.tok.position()
		is_used: true
	})
}

fn (mut p Parser) scope_register_ab() {
	p.scope.register(ast.Var{
		name: 'a'
		pos: p.tok.position()
		is_used: true
	})
	p.scope.register(ast.Var{
		name: 'b'
		pos: p.tok.position()
		is_used: true
	})
}

fn (mut p Parser) dot_expr(left ast.Expr) ast.Expr {
	p.next()
	if p.tok.kind == .dollar {
		return p.comptime_selector(left)
	}
	is_generic_call := p.is_generic_call()
	name_pos := p.tok.position()
	mut field_name := ''
	// check if the name is on the same line as the dot
	if (p.prev_tok.position().line_nr == name_pos.line_nr) || p.tok.kind != .name {
		field_name = p.check_name()
	} else {
		p.name_error = true
	}
	is_filter := field_name in ['filter', 'map', 'any', 'all']
	if is_filter || field_name == 'sort' {
		p.open_scope()
	}
	// ! in mutable methods
	if p.tok.kind == .not && p.peek_tok.kind == .lpar {
		p.next()
	}
	// Method call
	// TODO move to fn.v call_expr()
	mut concrete_types := []ast.Type{}
	mut concrete_list_pos := p.tok.position()
	if is_generic_call {
		// `g.foo<int>(10)`
		concrete_types = p.parse_concrete_types()
		concrete_list_pos = concrete_list_pos.extend(p.prev_tok.position())
		// In case of `foo<T>()`
		// T is unwrapped and registered in the checker.
		has_generic := concrete_types.any(it.has_flag(.generic))
		if !has_generic {
			// will be added in checker
			p.table.register_fn_concrete_types(field_name, concrete_types)
		}
	}
	if p.tok.kind == .lpar {
		p.next()
		args := p.call_args()
		p.check(.rpar)
		mut or_stmts := []ast.Stmt{}
		mut or_kind := ast.OrKind.absent
		mut or_pos := p.tok.position()
		if p.tok.kind == .key_orelse {
			was_inside_or_expr := p.inside_or_expr
			p.inside_or_expr = true
			p.next()
			p.open_scope()
			p.scope.register(ast.Var{
				name: 'err'
				typ: ast.error_type
				pos: p.tok.position()
				is_used: true
				is_stack_obj: true
			})
			or_kind = .block
			or_stmts = p.parse_block_no_scope(false)
			or_pos = or_pos.extend(p.prev_tok.position())
			p.close_scope()
			p.inside_or_expr = was_inside_or_expr
		}
		// `foo()?`
		if p.tok.kind == .question {
			p.next()
			or_kind = .propagate
		}
		//
		end_pos := p.prev_tok.position()
		pos := name_pos.extend(end_pos)
		comments := p.eat_comments(same_line: true)
		mcall_expr := ast.CallExpr{
			left: left
			name: field_name
			args: args
			name_pos: name_pos
			pos: pos
			is_method: true
			concrete_types: concrete_types
			concrete_list_pos: concrete_list_pos
			or_block: ast.OrExpr{
				stmts: or_stmts
				kind: or_kind
				pos: or_pos
			}
			scope: p.scope
			comments: comments
		}
		if is_filter || field_name == 'sort' {
			p.close_scope()
		}
		return mcall_expr
	}
	mut is_mut := false
	mut mut_pos := token.Position{}
	if p.inside_match || p.inside_if_expr {
		match left {
			ast.Ident, ast.SelectorExpr {
				is_mut = left.is_mut
				mut_pos = left.mut_pos
			}
			else {}
		}
	}
	pos := if p.name_error { left.position().extend(name_pos) } else { name_pos }
	sel_expr := ast.SelectorExpr{
		expr: left
		field_name: field_name
		pos: pos
		is_mut: is_mut
		mut_pos: mut_pos
		scope: p.scope
		next_token: p.tok.kind
	}
	if is_filter {
		p.close_scope()
	}
	return sel_expr
}

fn (mut p Parser) parse_generic_types() ([]ast.Type, []string) {
	mut types := []ast.Type{}
	mut param_names := []string{}
	if p.tok.kind != .lt {
		return types, param_names
	}
	p.check(.lt)
	mut first_done := false
	mut count := 0
	for p.tok.kind !in [.gt, .eof] {
		if first_done {
			p.check(.comma)
		}
		name := p.tok.lit
		if name.len > 0 && !name[0].is_capital() {
			p.error('generic parameter needs to be uppercase')
		}
		if name.len > 1 {
			p.error('generic parameter name needs to be exactly one char')
		}
		if !util.is_generic_type_name(p.tok.lit) {
			p.error('`$p.tok.lit` is a reserved name and cannot be used for generics')
		}
		if name in param_names {
			p.error('duplicated generic parameter `$name`')
		}
		if count > 8 {
			p.error('cannot have more than 9 generic parameters')
		}
		p.check(.name)
		param_names << name

		mut idx := p.table.find_type_idx(name)
		if idx == 0 {
			idx = p.table.register_type_symbol(ast.TypeSymbol{
				name: name
				cname: util.no_dots(name)
				mod: p.mod
				kind: .any
				is_public: true
			})
		}
		types << ast.new_type(idx).set_flag(.generic)
		first_done = true
		count++
	}
	p.check(.gt)
	return types, param_names
}

fn (mut p Parser) parse_concrete_types() []ast.Type {
	mut types := []ast.Type{}
	if p.tok.kind != .lt {
		return types
	}
	p.next() // `<`
	mut first_done := false
	for p.tok.kind !in [.eof, .gt] {
		if first_done {
			p.check(.comma)
		}
		types << p.parse_type()
		first_done = true
	}
	p.check(.gt) // `>`
	return types
}

// is_generic_name returns true if the current token is a generic name.
fn (p Parser) is_generic_name() bool {
	return p.tok.kind == .name && util.is_generic_type_name(p.tok.lit)
}

// `.green`
// `pref.BuildMode.default_mode`
fn (mut p Parser) enum_val() ast.EnumVal {
	start_pos := p.tok.position()
	p.check(.dot)
	val := p.check_name()
	return ast.EnumVal{
		val: val
		pos: start_pos.extend(p.prev_tok.position())
	}
}

fn (mut p Parser) filter_string_vet_errors(pos token.Position) {
	if p.vet_errors.len == 0 {
		return
	}
	p.vet_errors = p.vet_errors.filter(
		(it.typ == .trailing_space && it.pos.line_nr - 1 >= pos.last_line)
		|| (it.typ != .trailing_space && it.pos.line_nr - 1 > pos.last_line)
		|| (it.typ == .space_indent && it.pos.line_nr - 1 <= pos.line_nr)
		|| (it.typ != .space_indent && it.pos.line_nr - 1 < pos.line_nr))
}

fn (mut p Parser) string_expr() ast.Expr {
	is_raw := p.tok.kind == .name && p.tok.lit == 'r'
	is_cstr := p.tok.kind == .name && p.tok.lit == 'c'
	if is_raw || is_cstr {
		p.next()
	}
	mut node := ast.empty_expr()
	val := p.tok.lit
	mut pos := p.tok.position()
	pos.last_line = pos.line_nr + val.count('\n')
	if p.peek_tok.kind != .str_dollar {
		p.next()
		p.filter_string_vet_errors(pos)
		node = ast.StringLiteral{
			val: val
			is_raw: is_raw
			language: if is_cstr { ast.Language.c } else { ast.Language.v }
			pos: pos
		}
		return node
	}
	mut exprs := []ast.Expr{}
	mut vals := []string{}
	mut has_fmts := []bool{}
	mut fwidths := []int{}
	mut precisions := []int{}
	mut visible_pluss := []bool{}
	mut fills := []bool{}
	mut fmts := []byte{}
	mut fposs := []token.Position{}
	// Handle $ interpolation
	p.inside_str_interp = true
	for p.tok.kind == .string {
		vals << p.tok.lit
		p.next()
		if p.tok.kind != .str_dollar {
			break
		}
		p.next()
		exprs << p.expr(0)
		mut has_fmt := false
		mut fwidth := 0
		mut fwidthneg := false
		// 987698 is a magic default value, unlikely to be present in user input. NB: 0 is valid precision
		mut precision := 987698
		mut visible_plus := false
		mut fill := false
		mut fmt := `_` // placeholder
		if p.tok.kind == .colon {
			p.next()
			// ${num:-2d}
			if p.tok.kind == .minus {
				fwidthneg = true
				p.next()
			} else if p.tok.kind == .plus {
				visible_plus = true
				p.next()
			}
			// ${num:2d}
			if p.tok.kind == .number {
				fields := p.tok.lit.split('.')
				if fields[0].len > 0 && fields[0][0] == `0` {
					fill = true
				}
				fwidth = fields[0].int()
				if fwidthneg {
					fwidth = -fwidth
				}
				if fields.len > 1 {
					precision = fields[1].int()
				}
				p.next()
			}
			if p.tok.kind == .name {
				if p.tok.lit.len == 1 {
					fmt = p.tok.lit[0]
					has_fmt = true
					p.next()
				} else {
					return p.error('format specifier may only be one letter')
				}
			}
		}
		fwidths << fwidth
		has_fmts << has_fmt
		precisions << precision
		visible_pluss << visible_plus
		fmts << fmt
		fills << fill
		fposs << p.prev_tok.position()
	}
	pos = pos.extend(p.prev_tok.position())
	p.filter_string_vet_errors(pos)
	node = ast.StringInterLiteral{
		vals: vals
		exprs: exprs
		need_fmts: has_fmts
		fwidths: fwidths
		precisions: precisions
		pluss: visible_pluss
		fills: fills
		fmts: fmts
		fmt_poss: fposs
		pos: pos
	}
	// need_fmts: prelimery - until checker finds out if really needed
	p.inside_str_interp = false
	return node
}

fn (mut p Parser) parse_number_literal() ast.Expr {
	mut pos := p.tok.position()
	is_neg := p.tok.kind == .minus
	if is_neg {
		p.next()
		pos = pos.extend(p.tok.position())
	}
	lit := p.tok.lit
	full_lit := if is_neg { '-' + lit } else { lit }
	mut node := ast.empty_expr()
	if lit.index_any('.eE') >= 0 && lit[..2] !in ['0x', '0X', '0o', '0O', '0b', '0B'] {
		node = ast.FloatLiteral{
			val: full_lit
			pos: pos
		}
	} else {
		node = ast.IntegerLiteral{
			val: full_lit
			pos: pos
		}
	}
	p.next()
	return node
}

fn (mut p Parser) module_decl() ast.Module {
	mut module_attrs := []ast.Attr{}
	mut attrs_pos := p.tok.position()
	if p.tok.kind == .lsbr {
		p.attributes()
		module_attrs = p.attrs
	}
	mut name := 'main'
	is_skipped := p.tok.kind != .key_module
	mut module_pos := token.Position{}
	mut name_pos := token.Position{}
	mut mod_node := ast.Module{}
	if !is_skipped {
		p.attrs = []
		module_pos = p.tok.position()
		p.next()
		name_pos = p.tok.position()
		name = p.check_name()
		mod_node = ast.Module{
			pos: module_pos
		}
		if module_pos.line_nr != name_pos.line_nr {
			p.error_with_pos('`module` and `$name` must be at same line', name_pos)
			return mod_node
		}
		// NB: this shouldn't be reassigned into name_pos
		// as it creates a wrong position when extended
		// to module_pos
		n_pos := p.tok.position()
		if module_pos.line_nr == n_pos.line_nr && p.tok.kind != .comment && p.tok.kind != .eof {
			if p.tok.kind == .name {
				p.error_with_pos('`module $name`, you can only declare one module, unexpected `$p.tok.lit`',
					n_pos)
				return mod_node
			} else {
				p.error_with_pos('`module $name`, unexpected `$p.tok.kind` after module name',
					n_pos)
				return mod_node
			}
		}
		module_pos = attrs_pos.extend(name_pos)
	}
	full_name := util.qualify_module(p.pref, name, p.file_name)
	p.mod = full_name
	p.builtin_mod = p.mod == 'builtin'
	mod_node = ast.Module{
		name: full_name
		short_name: name
		attrs: module_attrs
		is_skipped: is_skipped
		pos: module_pos
		name_pos: name_pos
	}
	if !is_skipped {
		for ma in module_attrs {
			match ma.name {
				'manualfree' {
					p.is_manualfree = true
				}
				'generated' {
					p.is_generated = true
				}
				'has_globals' {
					if p.inside_vlib_file {
						p.has_globals = true
					} else {
						p.error_with_pos('[has_globals] is allowed only in .v files of `vlib` modules',
							ma.pos)
					}
				}
				else {
					p.error_with_pos('unknown module attribute `[$ma.name]`', ma.pos)
					return mod_node
				}
			}
		}
	}
	return mod_node
}

fn (mut p Parser) import_stmt() ast.Import {
	import_pos := p.tok.position()
	p.check(.key_import)
	mut pos := p.tok.position()
	mut import_node := ast.Import{
		pos: import_pos.extend(pos)
	}
	if p.tok.kind == .lpar {
		p.error_with_pos('`import()` has been deprecated, use `import x` instead', pos)
		return import_node
	}
	mut mod_name_arr := []string{}
	mod_name_arr << p.check_name()
	if import_pos.line_nr != pos.line_nr {
		p.error_with_pos('`import` statements must be a single line', pos)
		return import_node
	}
	mut mod_alias := mod_name_arr[0]
	import_node = ast.Import{
		pos: import_pos.extend(pos)
		mod_pos: pos
		alias_pos: pos
	}
	for p.tok.kind == .dot {
		p.next()
		submod_pos := p.tok.position()
		if p.tok.kind != .name {
			p.error_with_pos('module syntax error, please use `x.y.z`', submod_pos)
			return import_node
		}
		if import_pos.line_nr != submod_pos.line_nr {
			p.error_with_pos('`import` and `submodule` must be at same line', submod_pos)
			return import_node
		}
		submod_name := p.check_name()
		mod_name_arr << submod_name
		mod_alias = submod_name
		pos = pos.extend(submod_pos)
		import_node = ast.Import{
			pos: import_pos.extend(pos)
			mod_pos: pos
			alias_pos: submod_pos
			mod: util.qualify_import(p.pref, mod_name_arr.join('.'), p.file_name)
			alias: mod_alias
		}
	}
	if mod_name_arr.len == 1 {
		import_node = ast.Import{
			pos: import_node.pos
			mod_pos: import_node.mod_pos
			alias_pos: import_node.alias_pos
			mod: util.qualify_import(p.pref, mod_name_arr[0], p.file_name)
			alias: mod_alias
		}
	}
	mod_name := import_node.mod
	if p.tok.kind == .key_as {
		p.next()
		alias_pos := p.tok.position()
		mod_alias = p.check_name()
		if mod_alias == mod_name_arr.last() {
			p.error_with_pos('import alias `$mod_name as $mod_alias` is redundant', p.prev_tok.position())
			return import_node
		}
		import_node = ast.Import{
			pos: import_node.pos.extend(alias_pos)
			mod_pos: import_node.mod_pos
			alias_pos: alias_pos
			mod: import_node.mod
			alias: mod_alias
		}
	}
	if p.tok.kind == .lcbr { // import module { fn1, Type2 } syntax
		mut initial_syms_pos := p.tok.position()
		p.import_syms(mut import_node)
		initial_syms_pos = initial_syms_pos.extend(p.tok.position())
		import_node = ast.Import{
			...import_node
			syms_pos: initial_syms_pos
			pos: import_node.pos.extend(initial_syms_pos)
		}
		p.register_used_import(mod_alias) // no `unused import` msg for parent
	}
	pos_t := p.tok.position()
	if import_pos.line_nr == pos_t.line_nr {
		if p.tok.kind !in [.lcbr, .eof, .comment] {
			p.error_with_pos('cannot import multiple modules at a time', pos_t)
			return import_node
		}
	}
	import_node.comments = p.eat_comments(same_line: true)
	import_node.next_comments = p.eat_comments(follow_up: true)
	p.imports[mod_alias] = mod_name
	// if mod_name !in p.table.imports {
	p.table.imports << mod_name
	p.ast_imports << import_node
	// }
	return import_node
}

// import_syms parses the inner part of `import module { submod1, submod2 }`
fn (mut p Parser) import_syms(mut parent ast.Import) {
	p.next()
	pos_t := p.tok.position()
	if p.tok.kind == .rcbr { // closed too early
		p.error_with_pos('empty `$parent.mod` import set, remove `{}`', pos_t)
		return
	}
	if p.tok.kind != .name { // not a valid inner name
		p.error_with_pos('import syntax error, please specify a valid fn or type name',
			pos_t)
		return
	}
	for p.tok.kind == .name {
		pos := p.tok.position()
		alias := p.check_name()
		p.imported_symbols[alias] = parent.mod + '.' + alias
		// so we can work with this in fmt+checker
		parent.syms << ast.ImportSymbol{
			pos: pos
			name: alias
		}
		if p.tok.kind == .comma { // go again if more than one
			p.next()
			continue
		}
		if p.tok.kind == .rcbr { // finish if closing `}` is seen
			break
		}
	}
	if p.tok.kind != .rcbr {
		p.error_with_pos('import syntax error, no closing `}`', p.tok.position())
		return
	}
	p.next()
}

fn (mut p Parser) const_decl() ast.ConstDecl {
	p.top_level_statement_start()
	mut attrs := []ast.Attr{}
	if p.attrs.len > 0 {
		attrs = p.attrs
		p.attrs = []
	}
	mut is_markused := false
	for ga in attrs {
		match ga.name {
			'markused' { is_markused = true }
			else {}
		}
	}
	start_pos := p.tok.position()
	is_pub := p.tok.kind == .key_pub
	if is_pub {
		p.next()
	}
	const_pos := p.tok.position()
	p.check(.key_const)
	is_block := p.tok.kind == .lpar
	if is_block {
		p.next() // (
	}
	mut fields := []ast.ConstField{}
	mut comments := []ast.Comment{}
	for {
		comments = p.eat_comments()
		if is_block && p.tok.kind == .eof {
			p.error('unexpected eof, expecting ´)´')
			return ast.ConstDecl{}
		}
		if p.tok.kind == .rpar {
			break
		}
		pos := p.tok.position()
		name := p.check_name()
		if util.contains_capital(name) {
			p.warn_with_pos('const names cannot contain uppercase letters, use snake_case instead',
				pos)
		}
		full_name := p.prepend_mod(name)
		p.check(.assign)
		if p.tok.kind == .key_fn {
			p.error('const initializer fn literal is not a constant')
			return ast.ConstDecl{}
		}
		if p.tok.kind == .eof {
			p.error('unexpected eof, expecting an expression')
			return ast.ConstDecl{}
		}
		expr := p.expr(0)
		field := ast.ConstField{
			name: full_name
			mod: p.mod
			is_pub: is_pub
			expr: expr
			pos: pos.extend(expr.position())
			comments: comments
			is_markused: is_markused
		}
		fields << field
		p.table.global_scope.register(field)
		comments = []
		if !is_block {
			break
		}
	}
	p.top_level_statement_end()
	if is_block {
		p.check(.rpar)
	}
	return ast.ConstDecl{
		pos: start_pos.extend_with_last_line(const_pos, p.prev_tok.line_nr)
		fields: fields
		is_pub: is_pub
		end_comments: comments
		is_block: is_block
		attrs: attrs
	}
}

fn (mut p Parser) return_stmt() ast.Return {
	first_pos := p.tok.position()
	p.next()
	// no return
	mut comments := p.eat_comments()
	if p.tok.kind == .rcbr || (p.tok.kind == .name && p.peek_tok.kind == .colon) {
		return ast.Return{
			comments: comments
			pos: first_pos
		}
	}
	// return exprs
	exprs, comments2 := p.expr_list()
	comments << comments2
	end_pos := exprs.last().position()
	return ast.Return{
		exprs: exprs
		comments: comments
		pos: first_pos.extend(end_pos)
	}
}

// left hand side of `=` or `:=` in `a,b,c := 1,2,3`
fn (mut p Parser) global_decl() ast.GlobalDecl {
	mut attrs := []ast.Attr{}
	if p.attrs.len > 0 {
		attrs = p.attrs
		p.attrs = []
	}

	mut is_markused := false
	for ga in attrs {
		match ga.name {
			'markused' { is_markused = true }
			else {}
		}
	}

	if !p.has_globals && !p.pref.enable_globals && !p.pref.is_fmt && !p.pref.translated
		&& !p.pref.is_livemain && !p.pref.building_v && !p.builtin_mod {
		p.error('use `v -enable-globals ...` to enable globals')
		return ast.GlobalDecl{}
	}
	start_pos := p.tok.position()
	p.check(.key_global)
	is_block := p.tok.kind == .lpar
	if is_block {
		p.next() // (
	}
	mut fields := []ast.GlobalField{}
	mut comments := []ast.Comment{}
	for {
		comments = p.eat_comments()
		if is_block && p.tok.kind == .eof {
			p.error('unexpected eof, expecting ´)´')
			return ast.GlobalDecl{}
		}
		if p.tok.kind == .rpar {
			break
		}
		pos := p.tok.position()
		name := p.check_name()
		has_expr := p.tok.kind == .assign
		mut expr := ast.empty_expr()
		mut typ := ast.void_type
		mut typ_pos := token.Position{}
		if has_expr {
			p.next() // =
			expr = p.expr(0)
			match expr {
				ast.CastExpr {
					typ = (expr as ast.CastExpr).typ
				}
				ast.StructInit {
					typ = (expr as ast.StructInit).typ
				}
				ast.ArrayInit {
					typ = (expr as ast.ArrayInit).typ
				}
				ast.ChanInit {
					typ = (expr as ast.ChanInit).typ
				}
				ast.BoolLiteral, ast.IsRefType {
					typ = ast.bool_type
				}
				ast.CharLiteral {
					typ = ast.char_type
				}
				ast.FloatLiteral {
					typ = ast.f64_type
				}
				ast.IntegerLiteral, ast.SizeOf {
					typ = ast.int_type
				}
				ast.StringLiteral, ast.StringInterLiteral {
					typ = ast.string_type
				}
				else {
					// type will be deduced by checker
				}
			}
		} else {
			typ_pos = p.tok.position()
			typ = p.parse_type()
		}
		field := ast.GlobalField{
			name: name
			has_expr: has_expr
			expr: expr
			pos: pos
			typ_pos: typ_pos
			typ: typ
			comments: comments
			is_markused: is_markused
		}
		fields << field
		p.table.global_scope.register(field)
		comments = []
		if !is_block {
			break
		}
	}
	if is_block {
		p.check(.rpar)
	}
	return ast.GlobalDecl{
		pos: start_pos.extend(p.prev_tok.position())
		mod: p.mod
		fields: fields
		end_comments: comments
		is_block: is_block
		attrs: attrs
	}
}

fn (mut p Parser) enum_decl() ast.EnumDecl {
	p.top_level_statement_start()
	is_pub := p.tok.kind == .key_pub
	start_pos := p.tok.position()
	if is_pub {
		p.next()
	}
	p.check(.key_enum)
	end_pos := p.tok.position()
	enum_name := p.check_name()
	if enum_name.len == 1 {
		p.error_with_pos('single letter capital names are reserved for generic template types.',
			end_pos)
		return ast.EnumDecl{}
	}
	if enum_name in p.imported_symbols {
		p.error_with_pos('cannot register enum `$enum_name`, this type was already imported',
			end_pos)
		return ast.EnumDecl{}
	}
	name := p.prepend_mod(enum_name)
	p.check(.lcbr)
	enum_decl_comments := p.eat_comments()
	mut vals := []string{}
	// mut default_exprs := []ast.Expr{}
	mut fields := []ast.EnumField{}
	for p.tok.kind != .eof && p.tok.kind != .rcbr {
		pos := p.tok.position()
		val := p.check_name()
		vals << val
		mut expr := ast.empty_expr()
		mut has_expr := false
		// p.warn('enum val $val')
		if p.tok.kind == .assign {
			p.next()
			expr = p.expr(0)
			has_expr = true
		}
		fields << ast.EnumField{
			name: val
			pos: pos
			expr: expr
			has_expr: has_expr
			comments: p.eat_comments(same_line: true)
			next_comments: p.eat_comments()
		}
	}
	p.top_level_statement_end()
	p.check(.rcbr)
	is_flag := p.attrs.contains('flag')
	is_multi_allowed := p.attrs.contains('_allow_multiple_values')
	if is_flag {
		if fields.len > 32 {
			p.error('when an enum is used as bit field, it must have a max of 32 fields')
			return ast.EnumDecl{}
		}
		for f in fields {
			if f.has_expr {
				p.error_with_pos('when an enum is used as a bit field, you can not assign custom values',
					f.pos)
				return ast.EnumDecl{}
			}
		}
		pubfn := if p.mod == 'main' { 'fn' } else { 'pub fn' }
		p.codegen('
//
[inline] $pubfn (    e &$enum_name) is_empty() bool           { return  int(*e) == 0 }
[inline] $pubfn (    e &$enum_name) has(flag $enum_name) bool { return  (int(*e) &  (int(flag))) != 0 }
[inline] $pubfn (    e &$enum_name) all(flag $enum_name) bool { return  (int(*e) &  (int(flag))) == int(flag) }
[inline] $pubfn (mut e  $enum_name) set(flag $enum_name)      { unsafe{ *e = ${enum_name}(int(*e) |  (int(flag))) } }
[inline] $pubfn (mut e  $enum_name) clear(flag $enum_name)    { unsafe{ *e = ${enum_name}(int(*e) & ~(int(flag))) } }
[inline] $pubfn (mut e  $enum_name) toggle(flag $enum_name)   { unsafe{ *e = ${enum_name}(int(*e) ^  (int(flag))) } }
//
')
	}
	idx := p.table.register_type_symbol(ast.TypeSymbol{
		kind: .enum_
		name: name
		cname: util.no_dots(name)
		mod: p.mod
		info: ast.Enum{
			vals: vals
			is_flag: is_flag
			is_multi_allowed: is_multi_allowed
		}
		is_public: is_pub
	})
	if idx == -1 {
		p.error_with_pos('cannot register enum `$name`, another type with this name exists',
			end_pos)
	}

	enum_decl := ast.EnumDecl{
		name: name
		is_pub: is_pub
		is_flag: is_flag
		is_multi_allowed: is_multi_allowed
		fields: fields
		pos: start_pos.extend_with_last_line(end_pos, p.prev_tok.line_nr)
		attrs: p.attrs
		comments: enum_decl_comments
	}

	p.table.register_enum_decl(enum_decl)

	return enum_decl
}

fn (mut p Parser) type_decl() ast.TypeDecl {
	start_pos := p.tok.position()
	is_pub := p.tok.kind == .key_pub
	if is_pub {
		p.next()
	}
	p.check(.key_type)
	end_pos := p.tok.position()
	decl_pos := start_pos.extend(end_pos)
	name_pos := p.tok.position()
	name := p.check_name()
	if name.len == 1 && name[0].is_capital() {
		p.error_with_pos('single letter capital names are reserved for generic template types.',
			decl_pos)
		return ast.FnTypeDecl{}
	}
	if name in p.imported_symbols {
		p.error_with_pos('cannot register alias `$name`, this type was already imported',
			end_pos)
		return ast.AliasTypeDecl{}
	}
	mut sum_variants := []ast.TypeNode{}
	generic_types, _ := p.parse_generic_types()
	decl_pos_with_generics := decl_pos.extend(p.prev_tok.position())
	p.check(.assign)
	mut type_pos := p.tok.position()
	mut comments := []ast.Comment{}
	if p.tok.kind == .key_fn {
		// function type: `type mycallback = fn(string, int)`
		fn_name := p.prepend_mod(name)
		fn_type := p.parse_fn_type(fn_name)
		p.table.sym(fn_type).is_public = is_pub
		type_pos = type_pos.extend(p.tok.position())
		comments = p.eat_comments(same_line: true)
		return ast.FnTypeDecl{
			name: fn_name
			is_pub: is_pub
			typ: fn_type
			pos: decl_pos
			type_pos: type_pos
			comments: comments
		}
	}
	sum_variants << p.parse_sum_type_variants()
	// type SumType = A | B | c
	if sum_variants.len > 1 {
		for variant in sum_variants {
			variant_sym := p.table.sym(variant.typ)
			// TODO: implement this check for error too
			if variant_sym.kind == .none_ {
				p.error_with_pos('named sum type cannot have none as its variant', variant.pos)
				return ast.AliasTypeDecl{}
			}
		}
		variant_types := sum_variants.map(it.typ)
		prepend_mod_name := p.prepend_mod(name)
		typ := p.table.register_type_symbol(ast.TypeSymbol{
			kind: .sum_type
			name: prepend_mod_name
			cname: util.no_dots(prepend_mod_name)
			mod: p.mod
			info: ast.SumType{
				variants: variant_types
				is_generic: generic_types.len > 0
				generic_types: generic_types
			}
			is_public: is_pub
		})
		if typ == -1 {
			p.error_with_pos('cannot register sum type `$name`, another type with this name exists',
				name_pos)
			return ast.SumTypeDecl{}
		}
		comments = p.eat_comments(same_line: true)
		return ast.SumTypeDecl{
			name: name
			typ: typ
			is_pub: is_pub
			variants: sum_variants
			generic_types: generic_types
			pos: decl_pos
			comments: comments
		}
	}
	// type MyType = int
	if generic_types.len > 0 {
		p.error_with_pos('generic type aliases are not yet implemented', decl_pos_with_generics)
		return ast.AliasTypeDecl{}
	}
	// sum_variants will have only one element
	parent_type := sum_variants[0].typ
	parent_sym := p.table.sym(parent_type)
	pidx := parent_type.idx()
	p.check_for_impure_v(parent_sym.language, decl_pos)
	prepend_mod_name := p.prepend_mod(name)
	idx := p.table.register_type_symbol(ast.TypeSymbol{
		kind: .alias
		name: prepend_mod_name
		cname: util.no_dots(prepend_mod_name)
		mod: p.mod
		parent_idx: pidx
		info: ast.Alias{
			parent_type: parent_type
			language: parent_sym.language
		}
		is_public: is_pub
	})
	type_end_pos := p.prev_tok.position()
	if idx == -1 {
		p.error_with_pos('cannot register alias `$name`, another type with this name exists',
			name_pos)
		return ast.AliasTypeDecl{}
	}
	if idx == pidx {
		type_alias_pos := sum_variants[0].pos
		p.error_with_pos('a type alias can not refer to itself: $name', decl_pos.extend(type_alias_pos))
		return ast.AliasTypeDecl{}
	}
	comments = p.eat_comments(same_line: true)
	return ast.AliasTypeDecl{
		name: name
		is_pub: is_pub
		parent_type: parent_type
		type_pos: type_pos.extend(type_end_pos)
		pos: decl_pos
		comments: comments
	}
}

fn (mut p Parser) assoc() ast.Assoc {
	var_name := p.check_name()
	pos := p.tok.position()
	mut v := p.scope.find_var(var_name) or {
		p.error('unknown variable `$var_name`')
		return ast.Assoc{
			scope: 0
		}
	}
	v.is_used = true
	mut fields := []string{}
	mut vals := []ast.Expr{}
	p.check(.pipe)
	for p.tok.kind != .eof {
		fields << p.check_name()
		p.check(.colon)
		expr := p.expr(0)
		vals << expr
		if p.tok.kind == .comma {
			p.next()
		}
		if p.tok.kind == .rcbr {
			break
		}
	}
	return ast.Assoc{
		var_name: var_name
		fields: fields
		exprs: vals
		pos: pos
		scope: p.scope
	}
}

fn (p &Parser) new_true_expr() ast.Expr {
	return ast.BoolLiteral{
		val: true
		pos: p.tok.position()
	}
}

[noreturn]
fn verror(s string) {
	util.verror('parser error', s)
}

fn (mut p Parser) top_level_statement_start() {
	if p.comments_mode == .toplevel_comments {
		p.scanner.set_is_inside_toplevel_statement(true)
		p.rewind_scanner_to_current_token_in_new_mode()
		$if debugscanner ? {
			eprintln('>> p.top_level_statement_start | tidx:${p.tok.tidx:-5} | p.tok.kind: ${p.tok.kind:-10} | p.tok.lit: $p.tok.lit $p.peek_tok.lit ${p.peek_token(2).lit} ${p.peek_token(3).lit} ...')
		}
	}
}

fn (mut p Parser) top_level_statement_end() {
	if p.comments_mode == .toplevel_comments {
		p.scanner.set_is_inside_toplevel_statement(false)
		p.rewind_scanner_to_current_token_in_new_mode()
		$if debugscanner ? {
			eprintln('>> p.top_level_statement_end   | tidx:${p.tok.tidx:-5} | p.tok.kind: ${p.tok.kind:-10} | p.tok.lit: $p.tok.lit $p.peek_tok.lit ${p.peek_token(2).lit} ${p.peek_token(3).lit} ...')
		}
	}
}

fn (mut p Parser) rewind_scanner_to_current_token_in_new_mode() {
	// Go back and rescan some tokens, ensuring that the parser's
	// lookahead buffer p.peek_tok .. p.peek_token(3), will now contain
	// the correct tokens (possible comments), for the new mode
	// This refilling of the lookahead buffer is needed for the
	// .toplevel_comments parsing mode.
	tidx := p.tok.tidx
	p.scanner.set_current_tidx(tidx - 5)
	no_token := token.Token{}
	p.prev_tok = no_token
	p.tok = no_token
	p.peek_tok = no_token // requires 2 calls p.next() or check p.tok.kind != token.Kind.unknown
	p.next()
	for {
		p.next()
		// eprintln('rewinding to ${p.tok.tidx:5} | goal: ${tidx:5}')
		if tidx == p.tok.tidx {
			break
		}
	}
}

pub fn (mut p Parser) mark_var_as_used(varname string) bool {
	if obj := p.scope.find(varname) {
		match mut obj {
			ast.Var {
				obj.is_used = true
				return true
			}
			// ast.ConstField {
			// return true
			//}
			else {}
		}
	}
	return false
}

fn (mut p Parser) unsafe_stmt() ast.Stmt {
	mut pos := p.tok.position()
	p.next()
	if p.tok.kind != .lcbr {
		return p.error_with_pos('please use `unsafe {`', p.tok.position())
	}
	p.next()
	if p.inside_unsafe {
		return p.error_with_pos('already inside `unsafe` block', pos)
	}
	if p.tok.kind == .rcbr {
		// `unsafe {}`
		pos.update_last_line(p.tok.line_nr)
		p.next()
		return ast.Block{
			is_unsafe: true
			pos: pos
		}
	}
	p.inside_unsafe = true
	p.open_scope() // needed in case of `unsafe {stmt}`
	defer {
		p.inside_unsafe = false
		p.close_scope()
	}
	stmt := p.stmt(false)
	if p.tok.kind == .rcbr {
		if stmt is ast.ExprStmt {
			// `unsafe {expr}`
			if stmt.expr.is_expr() {
				p.next()
				pos.update_last_line(p.prev_tok.line_nr)
				ue := ast.UnsafeExpr{
					expr: stmt.expr
					pos: pos
				}
				// parse e.g. `unsafe {expr}.foo()`
				expr := p.expr_with_left(ue, 0, p.is_stmt_ident)
				return ast.ExprStmt{
					expr: expr
					pos: pos
				}
			}
		}
	}
	// unsafe {stmts}
	mut stmts := [stmt]
	for p.tok.kind != .rcbr {
		stmts << p.stmt(false)
	}
	p.next()
	pos.update_last_line(p.tok.line_nr)
	return ast.Block{
		stmts: stmts
		is_unsafe: true
		pos: pos
	}
}

fn (mut p Parser) trace(fbase string, message string) {
	if p.file_base == fbase {
		println('> p.trace | ${fbase:-10s} | $message')
	}
}