vlib: remove functions and fields, deprecated before 2023-03-20

* remove []int.reduce in favour of arrays.fold
  * remove datatypes.Set.equal in favour of datatypes.Set.==
  * remove datatypes.Set.difference in favour of datatypes.Set.-
  * remove gg.Context.set_cfg in favour of gg.Context.set_text_cfg
  * remove gg.Context.timage_pip in favour of gg.Context.pipeline.alpha
  * remove os.is_writable_folder in favour of os.ensure_folder_is_writable

  Discovered with `v run cmd/tools/show_ancient_deprecations.v 180`

vlib/builtin/array.v

@@ -968,20 +968,6 @@ pub fn copy(mut dst []u8, src []u8) int {
 	return min
 }
 
-// reduce executes a given reducer function on each element of the array,
-// resulting in a single output value.
-// NOTE: It exists as a method on `[]int` types only.
-// See also `arrays.reduce` for same name or `arrays.fold` for same functionality.
-[deprecated: 'use arrays.fold instead, this function has less flexibility than arrays.fold']
-[deprecated_after: '2022-10-11']
-pub fn (a []int) reduce(iter fn (int, int) int, accum_start int) int {
-	mut accum_ := accum_start
-	for i in a {
-		accum_ = iter(accum_, i)
-	}
-	return accum_
-}
-
 // grow_cap grows the array's capacity by `amount` elements.
 // Internally, it does this by copying the entire array to
 // a new memory location (creating a clone).

vlib/datatypes/set.v

@@ -46,12 +46,6 @@ pub fn (mut set Set[T]) clear() {
 	set.elements = map[T]u8{}
 }
 
-// equal checks whether the two given sets are equal (i.e. contain all and only the same elements).
-[deprecated: 'use set1[T] == set2[T] instead']
-pub fn (l Set[T]) equal(r Set[T]) bool {
-	return l == r
-}
-
 // == checks whether the two given sets are equal (i.e. contain all and only the same elements).
 pub fn (l Set[T]) == (r Set[T]) bool {
 	if l.elements.len != r.elements.len {
@@ -114,12 +108,6 @@ pub fn (l Set[T]) intersection(r Set[T]) Set[T] {
 	return set
 }
 
-// difference returns the difference of sets.
-[deprecated: 'use set1[T] - set2[T] instead']
-pub fn (l Set[T]) difference(r Set[T]) Set[T] {
-	return l - r
-}
-
 // - returns the difference of sets.
 pub fn (l Set[T]) - (r Set[T]) Set[T] {
 	mut set := l

vlib/gg/gg.c.v

@@ -168,7 +168,6 @@ pub mut:
 	height      int
 	clear_pass  gfx.PassAction
 	window      sapp.Desc
-	timage_pip  sgl.Pipeline       [deprecated: 'Use `Context.pipeline.alpha` instead!']
 	pipeline    &PipelineContainer = unsafe { nil }
 	config      Config
 	user_data   voidptr
@@ -259,10 +258,6 @@ fn gg_init_sokol_window(user_data voidptr) {
 	ctx.pipeline = &PipelineContainer{}
 	ctx.pipeline.init_pipeline()
 
-	// Keep the old pipeline for now, cuz v ui used it.
-	ctx.timage_pip = ctx.pipeline.alpha
-
-	//
 	if ctx.config.init_fn != unsafe { nil } {
 		$if android {
 			// NOTE on Android sokol can emit resize events *before* the init function is

vlib/gg/text_rendering.c.v

@@ -147,12 +147,6 @@ pub fn (ctx &Context) set_text_cfg(cfg gx.TextCfg) {
 	ctx.ft.fons.vert_metrics(&ascender, &descender, &lh)
 }
 
-// set_cfg sets the current text configuration
-[deprecated: 'use set_text_cfg() instead']
-pub fn (ctx &Context) set_cfg(cfg gx.TextCfg) {
-	ctx.set_text_cfg(cfg)
-}
-
 // draw_text draws the string in `text_` starting at top-left position `x`,`y`.
 // Text settings can be provided with `cfg`.
 pub fn (ctx &Context) draw_text(x int, y int, text_ string, cfg gx.TextCfg) {

vlib/os/os.v

@@ -920,9 +920,3 @@ pub fn config_dir() !string {
 	}
 	return error('Cannot find config directory')
 }
-
-[deprecated: 'use os.ensure_folder_is_writable instead']
-pub fn is_writable_folder(folder string) !bool {
-	ensure_folder_is_writable(folder)!
-	return true
-}

vlib/v/tests/reflection_sym_test.v

@@ -38,15 +38,15 @@ fn test_flag_result() {
 }
 
 fn test_array_sym() {
-	var := [1, 2]
+	var := ['abc', 'def']
 	typ := reflection.type_of(var)
 	assert typ.sym.kind == .array
 	assert typ.sym.language == .v
 	assert typ.sym.methods.len > 0
-	assert typ.sym.methods.filter(it.name == 'reduce').len > 0
-	assert typ.sym.name == '[]int'
+	assert typ.sym.methods.filter(it.name == 'join').len > 0
+	assert typ.sym.name == '[]string'
 	assert (typ.sym.info as reflection.Array).nr_dims == 1
-	assert (typ.sym.info as reflection.Array).elem_type == typeof[int]().idx
+	assert (typ.sym.info as reflection.Array).elem_type == typeof[string]().idx
 }
 
 fn test_sumtype_sym() {