Initial project import

tools/v/vlib/x/markdown/extension.v

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+// Copyright 2026 The V Language. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module markdown
+
+// Extension is the interface implemented by markdown extensions.
+// An extension configures the Markdown processor by enabling parser and
+// renderer features.
+pub interface Extension {
+	// extend is called once when the extension is registered with a Markdown processor.
+	extend(mut m Markdown)
+}
+
+// TableExt adds GitHub Flavored Markdown table support (| col | col |).
+pub struct TableExt {}
+
+// extend implements Extension for TableExt.
+pub fn (_ TableExt) extend(mut m Markdown) {
+	m.opts.tables = true
+}
+
+// StrikethroughExt adds GFM strikethrough support (~~text~~).
+pub struct StrikethroughExt {}
+
+// extend implements Extension for StrikethroughExt.
+pub fn (_ StrikethroughExt) extend(mut m Markdown) {
+	m.opts.strikethrough = true
+}
+
+// LinkifyExt adds autolink support for bare URLs and email addresses.
+pub struct LinkifyExt {}
+
+// extend implements Extension for LinkifyExt.
+pub fn (_ LinkifyExt) extend(mut m Markdown) {
+	m.opts.linkify = true
+}
+
+// TaskListExt adds GFM task list item support (- [ ] / - [x]).
+pub struct TaskListExt {}
+
+// extend implements Extension for TaskListExt.
+pub fn (_ TaskListExt) extend(mut m Markdown) {
+	m.opts.task_list = true
+}
+
+// FootnoteExt adds footnote support ([^label] references and [^label]: definitions).
+pub struct FootnoteExt {}
+
+// extend implements Extension for FootnoteExt.
+pub fn (_ FootnoteExt) extend(mut m Markdown) {
+	m.opts.footnotes = true
+}
+
+// TypographerExt replaces ASCII punctuation sequences with Unicode typographic
+// equivalents: -- en dash, --- em dash, ... ellipsis, and smart quotes.
+pub struct TypographerExt {}
+
+// extend implements Extension for TypographerExt.
+pub fn (_ TypographerExt) extend(mut m Markdown) {
+	m.opts.typographer = true
+}
+
+// DefinitionListExt adds Pandoc-style definition list support.
+pub struct DefinitionListExt {}
+
+// extend implements Extension for DefinitionListExt.
+pub fn (_ DefinitionListExt) extend(mut m Markdown) {
+	m.opts.definition_list = true
+}
+
+// table returns a TableExt extension value.
+pub fn table() TableExt {
+	return TableExt{}
+}
+
+// strikethrough returns a StrikethroughExt extension value.
+pub fn strikethrough() StrikethroughExt {
+	return StrikethroughExt{}
+}
+
+// linkify returns a LinkifyExt extension value.
+pub fn linkify() LinkifyExt {
+	return LinkifyExt{}
+}
+
+// task_list returns a TaskListExt extension value.
+pub fn task_list() TaskListExt {
+	return TaskListExt{}
+}
+
+// footnote returns a FootnoteExt extension value.
+pub fn footnote() FootnoteExt {
+	return FootnoteExt{}
+}
+
+// typographer returns a TypographerExt extension value.
+pub fn typographer() TypographerExt {
+	return TypographerExt{}
+}
+
+// definition_list returns a DefinitionListExt extension value.
+pub fn definition_list() DefinitionListExt {
+	return DefinitionListExt{}
+}
+
+// gfm returns the core GitHub Flavored Markdown extensions:
+// TableExt, StrikethroughExt, LinkifyExt, and TaskListExt.
+pub fn gfm() []Extension {
+	return [
+		Extension(TableExt{}),
+		StrikethroughExt{},
+		LinkifyExt{},
+		TaskListExt{},
+	]
+}