all: implement &&= and ||= (#21678)

vlib/v/checker/assign.v

@@ -673,6 +673,15 @@ or use an explicit `unsafe{ a[..] }`, if you do not want a copy of the slice.',
 						right.pos())
 				}
 			}
+			.boolean_and_assign, .boolean_or_assign {
+				if c.table.final_sym(left_type_unwrapped).kind != .bool {
+					c.error('operator ${node.op.str()} not defined on left operand type `${left_sym.name}`',
+						left.pos())
+				} else if c.table.final_sym(right_type_unwrapped).kind != .bool {
+					c.error('operator ${node.op.str()} not defined on right operand type `${right_sym.name}`',
+						right.pos())
+				}
+			}
 			.unsigned_right_shift_assign {
 				if node.left.len != 1 || node.right.len != 1 {
 					c.error('unsupported operation: unable to lower expression for unsigned shift assignment.',

vlib/v/checker/tests/mismatch_bool_assign_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/mismatch_bool_assign_err.vv:2:1: error: operator ||= not defined on left operand type `int`
+    1 | mut b := 12
+    2 | b ||= 34
+      | ^
+    3 | println(b)
+    4 |
+vlib/v/checker/tests/mismatch_bool_assign_err.vv:6:1: error: operator &&= not defined on left operand type `string`
+    4 | 
+    5 | mut c := 'str'
+    6 | c &&= 's'
+      | ^
+    7 | println(c)

vlib/v/checker/tests/mismatch_bool_assign_err.vv

@@ -0,0 +1,7 @@
+mut b := 12
+b ||= 34
+println(b)
+
+mut c := 'str'
+c &&= 's'
+println(c)

vlib/v/gen/c/assign.v

@@ -535,6 +535,28 @@ fn (mut g Gen) assign_stmt(node_ ast.AssignStmt) {
 					op_overloaded = true
 				}
 			}
+
+			if left_sym.kind == .bool && right_sym.kind == .bool
+				&& node.op in [.boolean_or_assign, .boolean_and_assign] {
+				extracted_op := match node.op {
+					.boolean_or_assign {
+						'||'
+					}
+					.boolean_and_assign {
+						'&&'
+					}
+					else {
+						'unknown op'
+					}
+				}
+				g.expr(left)
+				g.write(' = ')
+				g.expr(left)
+				g.write(' ${extracted_op} ')
+				g.expr(val)
+				g.writeln(';')
+				return
+			}
 			if right_sym.info is ast.FnType && is_decl {
 				if is_inside_ternary {
 					g.out.write_string(util.tabs(g.indent - g.inside_ternary))

vlib/v/scanner/scanner.v

@@ -872,6 +872,12 @@ pub fn (mut s Scanner) text_scan() token.Token {
 				}
 			}
 			`&` {
+				if nextc == `&` {
+					if s.look_ahead(2) == `=` {
+						s.pos += 2
+						return s.new_token(.boolean_and_assign, '', 3)
+					}
+				}
 				if nextc == `=` {
 					s.pos++
 					return s.new_token(.and_assign, '', 2)
@@ -885,6 +891,10 @@ pub fn (mut s Scanner) text_scan() token.Token {
 			}
 			`|` {
 				if nextc == `|` {
+					if s.look_ahead(2) == `=` {
+						s.pos += 2
+						return s.new_token(.boolean_or_assign, '', 3)
+					}
 					s.pos++
 					return s.new_token(.logical_or, '', 2)
 				}

vlib/v/tests/bool_assign_operator_test.v

@@ -0,0 +1,8 @@
+fn test_bool_assign_operator() {
+	mut flag := true
+	flag ||= false
+	assert flag == true
+
+	flag &&= false
+	assert flag == false
+}

vlib/v/token/token.v

@@ -67,6 +67,8 @@ pub enum Kind {
 	right_shift_assign // <<=
 	left_shift_assign // >>=
 	unsigned_right_shift_assign // >>>=
+	boolean_and_assign // &&=
+	boolean_or_assign // ||=
 	lcbr // {
 	rcbr // }
 	lpar // (
@@ -186,7 +188,7 @@ pub enum AtKind {
 
 pub const assign_tokens = [Kind.assign, .plus_assign, .minus_assign, .mult_assign, .div_assign,
 	.xor_assign, .mod_assign, .or_assign, .and_assign, .right_shift_assign, .left_shift_assign,
-	.unsigned_right_shift_assign]
+	.unsigned_right_shift_assign, .boolean_and_assign, .boolean_or_assign]
 
 pub const valid_at_tokens = ['@VROOT', '@VMODROOT', '@VEXEROOT', '@FN', '@METHOD', '@MOD', '@STRUCT',
 	'@VEXE', '@FILE', '@LINE', '@COLUMN', '@VHASH', '@VCURRENTHASH', '@VMOD_FILE', '@VMODHASH',
@@ -261,6 +263,8 @@ fn build_token_str() []string {
 	s[Kind.right_shift_assign] = '>>='
 	s[Kind.unsigned_right_shift_assign] = '>>>='
 	s[Kind.left_shift_assign] = '<<='
+	s[Kind.boolean_or_assign] = '||='
+	s[Kind.boolean_and_assign] = '&&='
 	s[Kind.lcbr] = '{'
 	s[Kind.rcbr] = '}'
 	s[Kind.lpar] = '('
@@ -468,6 +472,8 @@ pub fn build_precedences() []Precedence {
 	p[Kind.unsigned_right_shift_assign] = .assign
 	p[Kind.mult_assign] = .assign
 	p[Kind.xor_assign] = .assign
+	p[Kind.boolean_or_assign] = .assign
+	p[Kind.boolean_and_assign] = .assign
 	p[Kind.key_in] = .in_as
 	p[Kind.not_in] = .in_as
 	p[Kind.key_as] = .in_as
@@ -583,6 +589,8 @@ pub fn kind_to_string(k Kind) string {
 		.right_shift_assign { 'right_shift_assign' }
 		.left_shift_assign { 'left_shift_assign' }
 		.unsigned_right_shift_assign { 'unsigned_right_shift_assign' }
+		.boolean_and_assign { 'boolean_and_assign' }
+		.boolean_or_assign { 'boolean_or_assign' }
 		.lcbr { 'lcbr' }
 		.rcbr { 'rcbr' }
 		.lpar { 'lpar' }
@@ -707,6 +715,8 @@ pub fn kind_from_string(s string) !Kind {
 		'right_shift_assign' { .right_shift_assign }
 		'left_shift_assign' { .left_shift_assign }
 		'unsigned_right_shift_assign' { .unsigned_right_shift_assign }
+		'boolean_and_assign' { .boolean_and_assign }
+		'boolean_or_assign' { .boolean_or_assign }
 		'lcbr' { .lcbr }
 		'rcbr' { .rcbr }
 		'lpar' { .lpar }
@@ -793,6 +803,8 @@ pub fn assign_op_to_infix_op(op Kind) Kind {
 		.right_shift_assign { .right_shift }
 		.unsigned_right_shift_assign { .unsigned_right_shift }
 		.left_shift_assign { .left_shift }
+		.boolean_and_assign { .and }
+		.boolean_or_assign { .logical_or }
 		else { ._end_ }
 	}
 }