Move Markdown to inside the compiler. (crystal-lang#8115)

The Markdown module is buggy and not feature complete.
We shouldn't expose it in the standard library. For the compiler's
purposes (`crystal doc`) it might be good but users should be encouraged
to use a better library. Eventually the `crystal doc` tool should
somehow use a different, better markdown library.

spec/std/markdown/markdown_spec.cr → spec/compiler/crystal/tools/doc/markdown_spec.cr

@@ -1,13 +1,13 @@
 require "spec"
-require "markdown"
+require "../../../../../src/compiler/crystal/tools/doc/markdown"
 
 private def assert_render(input, output, file = __FILE__, line = __LINE__)
   it "renders #{input.inspect}", file, line do
-    Markdown.to_html(input).should eq(output), file, line
+    Crystal::Doc::Markdown.to_html(input).should eq(output), file, line
   end
 end
 
-describe Markdown do
+describe Crystal::Doc::Markdown do
   assert_render "", ""
   assert_render "Hello", "<p>Hello</p>"
   assert_render "Hello\nWorld", "<p>Hello\nWorld</p>"

src/compiler/crystal/tools/doc/generator.cr

@@ -303,7 +303,7 @@ class Crystal::Doc::Generator
     string = isolate_flag_lines string
     string += build_flag_lines_from_annotations context
     markdown = String.build do |io|
-      Markdown.parse string, MarkdownDocRenderer.new(context, io)
+      Markdown.parse string, Markdown::DocRenderer.new(context, io)
     end
     generate_flags markdown
   end

src/compiler/crystal/tools/doc/markdown_doc_renderer.cr → src/compiler/crystal/tools/doc/markdown/doc_renderer.cr

@@ -1,11 +1,13 @@
-require "markdown"
+require "./*"
 
-class Crystal::Doc::MarkdownDocRenderer < Markdown::HTMLRenderer
+class Crystal::Doc::Markdown::DocRenderer < Crystal::Doc::Markdown::HTMLRenderer
   def self.new(obj : Constant | Macro | Method, io)
     new obj.type, io
   end
 
-  def initialize(@type : Type, io)
+  @type : Crystal::Doc::Type
+
+  def initialize(@type : Crystal::Doc::Type, io)
     super(io)
 
     @inside_inline_code = false

src/markdown/html_renderer.cr → src/compiler/crystal/tools/doc/markdown/html_renderer.cr

@@ -1,6 +1,6 @@
 require "./renderer"
 
-class Markdown::HTMLRenderer
+class Crystal::Doc::Markdown::HTMLRenderer
   include Renderer
 
   def initialize(@io : IO)

src/compiler/crystal/tools/doc/markdown/markdown.cr

@@ -0,0 +1,36 @@
+# Basic implementation of Markdown for the `crystal doc` tool.
+#
+# It lacks many features and it has some bugs too. Eventually we should replace
+# it with something more feature-complete (like https://github.com/icyleaf/markd)
+# but that means the compiler will start depending on external shards. Otherwise
+# we should extract the doc as a separate tool/binary.
+# We don't expose this library in the standard library because it's probable
+# that we will never make it feature complete.
+#
+# Usage:
+#
+# ```
+# require "compiler/crystal/tools/doc/markdown"
+#
+# text = "## This is title \n This is a [link](http://crystal-lang.org)"
+#
+# Crystal::Doc::Markdown.to_html(text)
+# # => <h2>This is title</h2>
+# # => <p>This is a <a href="http://crystal-lang.org">link</a></p>
+# ```
+module Crystal::Doc::Markdown
+  def self.parse(text, renderer)
+    parser = Parser.new(text, renderer)
+    parser.parse
+  end
+
+  def self.to_html(text) : String
+    String.build do |io|
+      parse text, Markdown::HTMLRenderer.new(io)
+    end
+  end
+end
+
+require "./parser"
+require "./renderer"
+require "./html_renderer"

src/markdown/parser.cr → src/compiler/crystal/tools/doc/markdown/parser.cr

@@ -1,4 +1,4 @@
-class Markdown::Parser
+class Crystal::Doc::Markdown::Parser
   record PrefixHeader, count : Int32
   record UnorderedList, char : Char
   record CodeFence, language : String

src/markdown/renderer.cr → src/compiler/crystal/tools/doc/markdown/renderer.cr

@@ -1,4 +1,4 @@
-module Markdown::Renderer
+module Crystal::Doc::Markdown::Renderer
   abstract def begin_paragraph
   abstract def end_paragraph
   abstract def begin_italic

src/compiler/crystal/tools/playground/server.cr

@@ -1,8 +1,8 @@
 require "http/server"
 require "logger"
 require "ecr/macros"
-require "markdown"
 require "compiler/crystal/tools/formatter"
+require "compiler/crystal/tools/doc/markdown"
 
 module Crystal::Playground
   class Session
@@ -247,7 +247,7 @@ module Crystal::Playground
                   end
 
         if extname == ".md" || extname == ".cr"
-          content = Markdown.to_html(content)
+          content = Crystal::Doc::Markdown.to_html(content)
         end
         content
       rescue e

src/docs_main.cr

@@ -19,7 +19,6 @@ require "./llvm"
 require "./logger"
 require "./macros"
 require "./math/**"
-require "./markdown"
 require "./oauth"
 require "./oauth2"
 require "./openssl"