### Minimal REPLy Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/reply/README.md

This is a basic example demonstrating how to initialize and use the REPLy reader in a loop. It prints the evaluated expression back to the console.

```crystal
require "reply"

reader = Reply::Reader.new
reader.read_loop do |expression|
  # Eval expression here
  puts " => #{expression}"
end
```

--------------------------------

### Markdown List Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of equivalent list formatting in Markdown syntax. Demonstrates readability and structure.

```markdown
1.  List item one.

    List item one continued with a second paragraph followed by an
    Indented block.

        $ ls *.sh
        $ mv *.sh ~\/tmp

    List item continued with a third paragraph.

2.  List item two continued with an open block.

    This paragraph is part of the preceding list item.

    1. This list is nested and does not require explicit item continuation.

       This paragraph is part of the preceding list item.

    2. List item b.

    This paragraph belongs to item two of the outer list.

```

--------------------------------

### Install Boehm GC from Source

Source: https://github.com/crystal-lang/crystal/wiki/All-required-libraries

Installs the Boehm Garbage Collector from its Git repository. Ensure you have build tools like autoconf, automake, and a C++ compiler. This method is useful if your distribution's package is outdated.

```shell
git clone https://github.com/ivmai/bdwgc.git
cd bdwgc
./autogen.sh
./configure --enable-static --disable-shared --enable-large-config
make -j CFLAGS=-DNO_GETCONTEXT
make check
sudo make install
```

--------------------------------

### AsciiDoc List Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of list formatting in AsciiDoc syntax. This is provided for comparison with Markdown.

```asciidoc
1. List item one.
+
List item one continued with a second paragraph followed by an
Indented block.
+
.................
$ ls *.sh
$ mv *.sh ~\/tmp
.................
+
List item continued with a third paragraph.

2. List item two continued with an open block.
+
--
This paragraph is part of the preceding list item.

a. This list is nested and does not require explicit item
continuation.
+
This paragraph is part of the preceding list item.

b. List item b.

This paragraph belongs to item two of the outer list.
--

```

--------------------------------

### Install C++ Build Tools for Visual Studio 2019

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Installs the necessary C++ build tools and ATL component for LLVM. Keep the terminal open until the process completes.

```powershell
.\vs_buildtools.exe --passive --norestart --wait --add Microsoft.VisualStudio.Workload.VCTools --add Microsoft.VisualStudio.Component.VC.ATL --includeRecommended
```

--------------------------------

### Valid ordered list start number (9 digits)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Ordered list start numbers must be nine digits or less. This example shows a valid start number.

```markdown
123456789. ok
```

--------------------------------

### Install Debian/Ubuntu Build Dependencies

Source: https://github.com/crystal-lang/crystal/wiki/All-required-libraries

Installs necessary packages for building Crystal on Debian-based systems like Ubuntu. Includes build tools, development libraries for GMP, event, SSL, PCRE2, and XML/YAML.

```shell
sudo apt-get install -y \
  automake \
  build-essential \
  git \
  libbsd-dev \
  libevent-dev \
  libgmp-dev \
  libgmpxx4ldbl \
  libpcre2-dev \
  libssl-dev \
  libtool \
  libxml2-dev \
  libyaml-dev \
  lld \
  llvm \
  llvm-dev \
  libz-dev
```

--------------------------------

### Install Git Pre-commit Hook

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Install the pre-commit hook to ensure code is formatted correctly before each commit. This hook runs `crystal tool format`.

```sh
ln -s scripts/git/pre-commit .git/hooks
```

--------------------------------

### Build Example Program on Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Builds a Crystal program ('hello.cr') on Windows using a locally compiled Crystal executable. Sets necessary environment variables.

```cmd
set CRYSTAL_PATH=src
set LIB=%LIB%;C:\crystal
set TERM=dumb
crystal.exe build hello.cr
```

--------------------------------

### Running an HTTP Server with Crystal

Source: https://github.com/crystal-lang/crystal/blob/master/src/compiler/crystal/tools/playground/views/_about.html

Demonstrates how to create and run a basic HTTP server using the `http/server` library. This example shows how to handle requests and send responses.

```crystal
require "http/server"

server = HTTP::Server.new do |context|
  context.request.path
  context.response.headers["Content-Type"] = "text/plain"
  context.response.print("Hello world!")
end
server.bind_tcp "0.0.0.0", 5678

puts "Listening on http://0.0.0.0:5678"
server.listen
```

--------------------------------

### Install Fedora Build Dependencies

Source: https://github.com/crystal-lang/crystal/wiki/All-required-libraries

Installs required packages for building Crystal on Fedora. Includes C/C++ compilers, development libraries for GMP, event, SSL, PCRE2, and XML/YAML, along with LLVM and make.

```shell
sudo dnf -y install \
  gcc \
  gcc-c++ \
  gmp-devel \
  libbsd-devel \
  libevent-devel \
  libxml2-devel \
  libyaml-devel \
  llvm-devel \
  llvm-static \
  libstdc++-static \
  make \
  openssl-devel \
  pcre2-devel \
  redhat-rpm-config
```

--------------------------------

### HTML Block Example with Nested Pre

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates how an HTML block, started by '<table>', is terminated by a blank line, even if it contains a '<pre>' tag. Regular Markdown parsing resumes afterward.

```markdown
<table><tr><td>
<pre>
**Hello**,

_world_.
</pre>
</td></tr></table>
.
table><tr><td>
<pre>
**Hello**,
<p><em>world</em>.
</pre></p>
</td></tr></table>
```

--------------------------------

### Markdown.pl Two-Space Indentation Example (HTML Output)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows the HTML output for the `Markdown.pl` two-space indentation example, where 'two' is parsed as a continuation paragraph of the list item.

```html
<ul>
<li>
<p>one</p>
<p>two</p>
</li>
</ul>
```

--------------------------------

### Basic HTML Block Example (Type 6)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates a basic HTML block of type 6, starting with '<table>' and ending at a blank line. The content within the block is treated as raw HTML.

```markdown
<table>
  <tr>
    <td>
           hi
    </td>
  </tr>
</table>

okay.
.
<table>
  <tr>
    <td>
           hi
    </td>
  </tr>
</table>
<p>okay.</p>
```

--------------------------------

### Install macOS Build Dependencies with Homebrew

Source: https://github.com/crystal-lang/crystal/wiki/All-required-libraries

Installs essential libraries for building Crystal on macOS using Homebrew. Includes Boehm GC, GMP, libevent, libxml2, libyaml, LLVM, OpenSSL, PCRE2, and pkg-config.

```shell
xcode-select --install
brew install \
  bdw-gc \
  gmp \
  libevent \
  libxml2 \
  libyaml \
  llvm \
  openssl \
  pcre2 \
  pkg-config
```

--------------------------------

### Install Markd Dependency

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/README.md

Add the Markd gem to your application's shard.yml file for installation.

```yaml
dependencies:
  markd:
    github: icyleaf/markd
```

--------------------------------

### Customizing REPLy Interface

Source: https://github.com/crystal-lang/crystal/blob/master/lib/reply/README.md

This example shows how to extend the `Reply::Reader` class to customize the REPL interface. It includes methods for defining a custom prompt, syntax highlighting, multi-line input logic, auto-formatting, indentation, history saving, and auto-completion.

```crystal
require "reply"

class MyReader < Reply::Reader
  def prompt(io : IO, line_number : Int32, color : Bool) : Nil
    # Display a custom prompt
  end

  def highlight(expression : String) : String
    # Highlight the expression
  end

  def continue?(expression : String) : Bool
    # Return whether the interface should continue on multiline, depending of the expression
  end

  def format(expression : String) : String?
    # Reformat when expression is submitted
  end

  def indentation_level(expression_before_cursor : String) : Int32?
    # Compute the indentation from the expression
  end

  def save_in_history?(expression : String) : Bool
    # Return whether the expression is saved in history
  end

  def auto_complete(name_filter : String, expression : String) : {String, Array(String)}
    # Return the auto-completion result from expression
  end
end
```

--------------------------------

### URI Autolink Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a basic URI autolink. Ensure the URI is absolute and enclosed in angle brackets.

```markdown
<http://foo.bar.baz>
.
<p><a href="http://foo.bar.baz">http://foo.bar.baz</a></p>
```

--------------------------------

### Download and Build LLVM Source for Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads LLVM source code and builds it using CMake for Windows. This requires Python and 7-Zip to be installed.

```powershell
iwr https://github.com/llvm/llvm-project/releases/download/llvmorg-10.0.0/llvm-10.0.0.src.tar.xz -OutFile llvm.tar.xz
& "C:\Program Files\7-Zip\7z.exe" x llvm.tar.xz
& "C:\Program Files\7-Zip\7z.exe" x llvm.tar
move llvm-* llvm
```

```powershell
cd llvm
cmake . -DBUILD_SHARED_LIBS=OFF -Thost=x64 -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_USE_CRT_RELEASE=MT
cmake --build . --config Release
```

--------------------------------

### Flexible Indentation Example (Markdown)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example demonstrating a more flexible indentation rule where a continuation paragraph ('bar') is considered part of the list item even if not indented as far as the first paragraph ('foo'), as long as it's indented relative to the list marker.

```markdown
 10. foo

   bar  
```

--------------------------------

### Markdown Emphasis and Strong Emphasis Examples

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates various ways to achieve strong emphasis and nested emphasis using asterisks and underscores in Markdown.

```markdown
***strong emph***
***strong** in emph*
***emph* in strong**
**in strong *emph***
*in emph **strong***
```

```markdown
*emph *with emph* in it*
**strong **with strong** in it**
```

```markdown
internal emphasis: foo*bar*baz
no emphasis: foo_bar_baz
```

--------------------------------

### HTML Block: Non-standard Tag Start

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an HTML block where the initial tag starts like a tag but contains non-standard characters.

```html
<div *???-&&&-<---
*foo*
.
```

--------------------------------

### Markdown.pl Indented Blockquote Example (HTML Output)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Presents the HTML output for the `Markdown.pl` indented blockquote example, demonstrating nested list item parsing within a blockquote.

```html
<blockquote>
<ul>
<li>
<p>one</p>
<p>two</p>
</li>
</ul>
</blockquote>
```

--------------------------------

### HTML Block: Pre Tag Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of a `<pre>` tag (type 1 block) which can contain blank lines and ends at the corresponding end tag.

```html
<pre language="haskell"><code>
import Text.HTML.TagSoup

main :: IO ()
main = print $ parseTags tags
</code></pre>
okay
.
```

--------------------------------

### HTML Block: Style Tag Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of a `<style>` tag (type 1 block) that can contain blank lines and ends at the corresponding end tag.

```css
<style
  type="text/css">
h1 {color:red;}

p {color:blue;}
</style>
okay
.
```

--------------------------------

### Non-entities Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Examples of strings that are not recognized as valid entity or numeric character references, including malformed ones.

```html
&nbsp &x; &#; &#x;
&#987654321;
&#abcdef0;
&ThisIsNotDefined; &hi?;
.
```

```html
<p>&amp;nbsp &amp;x; &amp;#; &amp;#x;
&amp;#987654321;
&amp;#abcdef0;
&amp;ThisIsNotDefined; &amp;hi?;</p>
```

--------------------------------

### Basic HTML Block Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a simple HTML block within Markdown. The content inside the block is rendered as HTML.

```markdown
<div>
- foo
. 
<ul>
<li>
<div>
</li>
<li>foo</li>
</ul>
```

--------------------------------

### Ordered List Item with Content

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates an ordered list item with a start number of 1, showing how its content is structured similarly to a basic list item.

```markdown
1.  A paragraph
    with two lines.

        indented code

    > A block quote.
.
```

--------------------------------

### Empty Emphasis and Strong Emphasis Not Allowed

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows examples that are not considered empty emphasis or strong emphasis.

```markdown
** is not an empty emphasis
```

```markdown
**** is not an empty strong emphasis
```

```markdown
__ is not an empty emphasis
```

```markdown
____ is not an empty strong emphasis
```

--------------------------------

### Markdown Empty List Item at Start

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates an empty list item at the beginning of a list. This is valid and renders as an empty list element.

```markdown
*

```

```html
<ul>
<li></li>
</ul>
```

--------------------------------

### Example of Nested Code Spans

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates the use of nested backticks within a code span. This is useful for showing code examples that themselves contain backticks.

```markdown
`foo``bar`
```

--------------------------------

### HTML Block: Script Tag Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of a `<script>` tag (type 1 block) that can contain blank lines and ends at the corresponding end tag.

```javascript
<script type="text/javascript">
// JavaScript example

document.getElementById("demo").innerHTML = "Hello JavaScript!";
</script>
okay
.
```

--------------------------------

### Document Tree Structure Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates a possible document tree structure, showing nested blocks like block_quote, list, and list_item. Open blocks are indicated by arrows.

```tree
-> document
  -> block_quote
       paragraph
         "Lorem ipsum dolor\nsit amet."
    -> list (type=bullet tight=true bullet_char=-) 
         list_item
           paragraph
             "Qui *quodsi iracundia*"
      -> list_item
        -> paragraph
             "aliquando id"
```

--------------------------------

### Empty List Item

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an example of an empty list item, raising questions about its validity and rendering.

```markdown
* a
*
* b

```

--------------------------------

### Delimiter Run Examples in Markdown

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates different types of delimiter runs (left-flanking, right-flanking, or both) used in Markdown emphasis parsing.

```markdown
***abc
  _abc
**"abc"
 _"abc"
```

```markdown
 abc***
 abc_
"abc"**
"abc"_
```

```markdown
 abc***def
"abc"_"def"
```

```markdown
abc *** def
a _ b
```

--------------------------------

### Format Code According to Style Guide

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Use 'crystal tool format' to automatically format your code, ensuring it adheres to the project's coding style guidelines.

```shell
crystal tool format
```

--------------------------------

### Setext Heading Level 1 and 2 Examples

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates the creation of level 1 and level 2 Setext headings using '=' and '-' underlines respectively. The content is parsed as CommonMark inline.

```markdown
Foo *bar*
=========

Foo *bar*
---------
```

--------------------------------

### Basic Block Quote Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a standard block quote with a heading and paragraphs. Requires a '>' followed by a space at the beginning of each line.

```markdown
> # Foo
> bar
> baz
```

```html
<blockquote>
<h1>Foo</h1>
<p>bar
baz</p>
</blockquote>
```

--------------------------------

### Indented HTML Start Tag (Valid)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows that an HTML start tag can be indented with 1-3 spaces and still be recognized as an HTML block. Indentation of 4 spaces is not allowed.

```markdown
  <!-- foo -->

    <!-- foo -->.
  <!-- foo -->
<pre><code>&lt;!-- foo --&gt;
</code></pre>
```

```markdown
  <div>

    <div>
. 
  <div>
<pre><code>&lt;div&gt;
</code></pre>
```

--------------------------------

### HTML Table Structure

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a basic HTML table structure. This is an example of how HTML content might be represented.

```html
<table>

  <tr>

    <td>
      Hi
    </td>

  </tr>

</table>
```

--------------------------------

### Emphasis and Strong Emphasis Precedence

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an example of ambiguous precedence rules between emphasis and strong emphasis markers.

```markdown
*foo *bar* baz*

```

--------------------------------

### Ruby Trailing While Example

Source: https://github.com/crystal-lang/crystal/wiki/FAQ

Demonstrates the syntax for a trailing 'while' loop in Ruby, which first checks the condition and then executes the code block.

```ruby
# This one first checks <condition> and then executes <code>
<code> while <condition>
```

--------------------------------

### Email Autolink Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a valid email address enclosed in angle brackets, parsed as a 'mailto:' link.

```markdown
<foo@bar.example.com>
.
<p><a href="mailto:foo@bar.example.com">foo@bar.example.com</a></p>
```

--------------------------------

### Invalid ordered list start number (negative)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Ordered list start numbers cannot be negative. This example shows an invalid negative start number.

```markdown
-1. not ok
```

--------------------------------

### Smart Quotes Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/smart_punct.txt

Demonstrates matching of open and closed double quotes. Use this for standard text quotation.

```text
"Hello," said the spider.
"'Shelob' is my name."
.
```

--------------------------------

### Valid ordered list start number with leading zeros

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Ordered list start numbers can have leading zeros, which are interpreted correctly. This example shows a valid start number with leading zeros.

```markdown
0. ok
```

```markdown
003. ok
```

--------------------------------

### Generate Standard Library Documentation

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Execute 'make docs' to generate the standard library documentation. Ensure your code follows the documented conventions.

```shell
make docs
```

--------------------------------

### Invalid ordered list start number (10 digits)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Ordered list start numbers exceeding nine digits are not rendered as ordered lists. This example shows an invalid start number.

```markdown
1234567890. not ok
```

--------------------------------

### Markdown Link Reference Definition Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a basic link reference definition and its usage. The definition `[bar]: /baz` is followed by a reference `[bar]` which is rendered as a link.

```markdown
Foo
[bar]: /baz

[bar]
```

```html
<p>Foo
[bar]: /baz</p>
<p><a href="/baz">bar</a></p>
```

--------------------------------

### Code Span vs. HTML Tag Precedence

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Code spans and HTML tags share the same precedence. This example is treated as code because it starts with '<' followed by a backtick.

```markdown
```````````````````````````````` example
`<a href="`">
.
```

--------------------------------

### Image with Space Between Brackets

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An image syntax example demonstrating that whitespace is not allowed between the description brackets and the reference label brackets.

```markdown
![foo] 
[]

[foo]: /url "title"
```

```html
<p><img src="/url" alt="foo" title="title" />
[]</p>
```

--------------------------------

### HTML Block with Partial Tag Start

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates an HTML block where the opening tag is split across lines. The block is terminated by a blank line, and the content is treated as raw HTML.

```markdown
<div id="foo"
  class="bar">
</div>
.
<div id="foo"
  class="bar">
</div>
```

--------------------------------

### List Available Make Targets

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Use 'make help' to view a comprehensive list of all available make targets for building, testing, and managing the Crystal project.

```shell
make help
```

--------------------------------

### Markdown List Interruption Rule

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an example where a numeral in a hard-wrapped line does not trigger a list, contrasting with CommonMark's behavior for lists starting with '1'.

```markdown
The number of windows in my house is
14.  The number of doors is 6.
```

```html
<p>The number of windows in my house is
14.  The number of doors is 6.</p>
```

--------------------------------

### Smart Single Quotes Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/smart_punct.txt

Demonstrates matching of open and closed single quotes. Use this for nested quotations or specific stylistic choices.

```text
'A', 'B', and 'C' are letters.
.

```

--------------------------------

### Numbered List as First Block in List Item

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates a list item starting with a numbered list, showing how different list types can be nested.

```markdown
1. - 2. foo
```

```html
<ol>
<li>
<ul>
<li>
<ol start="2">
<li>foo</li>
</ol>
</li>
</ul>
</li>
</ol>
```

--------------------------------

### Four-Space Rule Example (HTML Output)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows the HTML output generated by adhering to the four-space rule, which parses the above Markdown as two separate lists with an intervening paragraph.

```html
<ul>
<li>foo</li>
</ul>
<p>bar</p>
<ul>
<li>baz</li>
</ul>
```

--------------------------------

### Example of List Item Content

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates the content of a list item when parsed from Markdown, showing how paragraphs, code blocks, and block quotes are structured.

```markdown
A paragraph
with two lines.

    indented code

> A block quote.
.
```

--------------------------------

### Link Hello World executable on Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Links the compiled object file into an executable on Windows using the MSVC linker. Ensure you are in the C:\crystal directory and have the necessary libraries.

```cmd
cd C:\crystal
cl hello_world.obj "/Fehello_world" pcre.lib gc.lib advapi32.lib legacy_stdio_definitions.lib libcmt.lib
.\hello_world.exe
```

--------------------------------

### Build libyaml for Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Builds the libyaml library using CMake for Windows. Ensure you are in the libyaml directory before running.

```bash
cd libyaml
cmake . -DCMAKE_POLICY_DEFAULT_CMP0091=NEW -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DCMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH=OFF
cmake --build . --config Release
cd ..
```

--------------------------------

### Markdown.pl Indented Blockquote Example (Markdown)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates `Markdown.pl`'s handling of list items within blockquotes, showing how indentation rules apply.

```markdown
>   - one
> 
>  two
```

--------------------------------

### Set Up Appointment (JavaScript)

Source: https://github.com/crystal-lang/crystal/blob/master/spec/std/data/large_single_line_string.txt

This function is used to set up an appointment with specific parameters including an ID, coordinates, and a boolean flag. Ensure all parameters are correctly provided.

```javascript
javascript:SetUpAppoint('67','3', '3-8687600', '27683', '15', 'false'); return false;
```

```javascript
javascript:SetUpAppoint('68','2', '2', '14451', 'false'); return false;
```

--------------------------------

### Build the Crystal Compiler

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Run 'make crystal' to build the compiler. The executable will be located at '.build/compiler'. Use the 'bin/crystal' wrapper script to run it.

```shell
make crystal
```

--------------------------------

### Crystal Class Definition Example

Source: https://github.com/crystal-lang/crystal/wiki/Compiler-internals

Illustrates a nested class definition with a method, which the type inference stage processes to declare types and methods.

```crystal
class Foo
  class Bar
    def baz
      1
    end
  end
end
```

--------------------------------

### Run Compiler Specifications

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Execute 'make compiler_spec' to run the compiler's specifications. Use 'make primitives_spec' for primitive method specs.

```shell
make compiler_spec
```

```shell
make primitives_spec
```

--------------------------------

### Cross-compile Hello World for Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Compiles a simple 'Hello World' program for Windows using Crystal's cross-compilation feature. This generates an object file and a suggested linker command.

```bash
echo 'puts "Hello world!"' > hello_world.cr
bin/crystal build --cross-compile --target x86_64-pc-windows-msvc hello_world.cr
```

--------------------------------

### Markdown.pl Two-Space Indentation Example (Markdown)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates the behavior of `Markdown.pl` where a paragraph following a list item can be indented with fewer spaces than the list marker, still being considered part of the list item.

```markdown
   - one

  two
```

--------------------------------

### Hexadecimal Numeric Character References Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates hexadecimal numeric character references, parsed as their corresponding Unicode characters using hexadecimal notation.

```html
&#X22; &#XD06; &#xcab;
.
```

```html
<p>&quot; ആ ಫ</p>
```

--------------------------------

### Using puts for Output in Crystal

Source: https://github.com/crystal-lang/crystal/blob/master/src/compiler/crystal/tools/playground/views/_about.html

Shows how to use the `puts` method to print output, which appears in the bottom panel of the playground. Note that `puts` returns `nil`.

```crystal
s = "Lorem ipsum"
puts s
```

--------------------------------

### Changing Bullet or Ordered List Delimiters

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates how changing the list marker (e.g., from '-' to '+') starts a new list. Shows the resulting HTML for both bullet and ordered lists.

```markdown
- foo
- bar
+ baz
```

```html
<ul>
<li>foo</li>
<li>bar</li>
</ul>
<ul>
<li>baz</li>
</ul>
```

```markdown
1. foo
2. bar
3) baz
```

```html
<ol>
<li>foo</li>
<li>bar</li>
</ol>
<ol start="3">
<li>baz</li>
</ol>
```

--------------------------------

### Build libz for Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Builds the zlib library using CMake for Windows. Ensure you are in the zlib directory before running.

```bash
cd zlib
cmake . -DCMAKE_POLICY_DEFAULT_CMP0091=NEW -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DCMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH=OFF
cmake --build . --config Release
cd ..
```

--------------------------------

### Download and Build libgc

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads and builds the libgc library, a garbage collector, for use with Crystal. Ensure the destination path is correctly set.

```powershell
# Download libgc
iwr https://github.com/ivmai/bdwgc/archive/2fd48a92b8bff3afb64b3528ad78b63f033f0436.zip -OutFile bdwgc.zip
Expand-Archive bdwgc.zip -DestinationPath .
mv bdwgc-* bdwgc

# Download libatomic_ops
iwr https://github.com/ivmai/libatomic_ops/archive/v7.6.10.zip -OutFile libatomic_ops.zip
Expand-Archive libatomic_ops.zip -DestinationPath .
mv libatomic_ops-* bdwgc\libatomic_ops

# Build libgc
cd bdwgc
cmake . -DBUILD_SHARED_LIBS=OFF -Denable_large_config=ON -DCMAKE_POLICY_DEFAULT_CMP0091=NEW -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded
cmake --build . --config Release
cd ..
```

--------------------------------

### Build an Executable Crystal Program

Source: https://github.com/crystal-lang/crystal/blob/master/doc/man/crystal.adoc

Use the 'build' command to compile a Crystal program into an executable file. By default, the executable will have the same name as the source file.

```shell
crystal build some_program.cr
```

--------------------------------

### Custom Markdown Renderer

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/README.md

Extend the Markd::Renderer class to create a custom renderer. Override methods like 'strong' to modify how specific markdown elements are processed. This example shows how to parse markdown with custom options and then render it using the custom renderer.

```crystal
class CustomRenderer < Markd::Renderer

  def strong(node, entering)
  end

  # more methods following in render.
end

options = Markd::Options.new(time: true)
document = Markd.parse(markdown, options)
renderer = CustomRenderer.new(options)

html = renderer.render(document)
```

--------------------------------

### Download and Build mpir

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads and builds the MPIR library, a multi-precision integer library. This command uses MSBuild to compile the project.

```powershell
# Download mpir
iwr https://github.com/BrianGladman/mpir/archive/d9c9a842be6475bef74324f367ce2c5a78c55d06.zip -OutFile mpir.zip
Expand-Archive mpir.zip -DestinationPath .
mv mpir* mpir

# Build mpir
cd mpir
MSBuild.exe /p:Platform=x64 /p:Configuration=Release /p:DefineConstants=MSC_BUILD_DLL ".\msvc\vs19\lib_mpir_gc\lib_mpir_gc.vcxproj"
cd ..

mv mpir\lib\x64\Release\mpir.lib .

```

--------------------------------

### HTML Block: Closing Tag Only

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an HTML block starting with only a closing tag.

```html
</ins>
*bar*
.
```

--------------------------------

### Made-up Scheme Autolink

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of an autolink with a made-up scheme, which is still parsed as a link.

```markdown
<made-up-scheme://foo,bar>
.
<p><a href="made-up-scheme://foo,bar">made-up-scheme://foo,bar</a></p>
```

--------------------------------

### HTML Block: Table Structure

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of an HTML block containing a table structure.

```html
<table><tr><td>
foo
</td></tr></table>
.
```

--------------------------------

### Emphasis with Literal Asterisks

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Examples of emphasis containing literal asterisks, including escaped ones.

```markdown
foo ***
```

```markdown
foo *\**
```

```markdown
foo *_*
```

```markdown
foo *****
```

```markdown
foo **\***
```

```markdown
foo **_**
```

--------------------------------

### Download and Build libxml2

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads and builds the libxml2 library, used for XML parsing. It's configured to disable HTTP/FTP support and tests, and uses a multi-threaded runtime.

```powershell
# Download libxml2
iwr https://github.com/GNOME/libxml2/archive/a230b728f1289dd24c1666856ac4fb55579c6dfb.zip -OutFile libxml2.zip
Expand-Archive libxml2.zip -DestinationPath .
mv libxml2* libxml2

# Build libxml2
cd libxml2
cmake . -DBUILD_SHARED_LIBS=OFF -DLIBXML2_WITH_HTTP=OFF -DLIBXML2_WITH_FTP=OFF -DLIBXML2_WITH_TESTS=OFF -DCMAKE_POLICY_DEFAULT_CMP0091=NEW -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DCMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH=OFF
cmake --build . --config Release
cd ..

mv libxml2\Release\xml2.lib .

```

--------------------------------

### Not an Autolink: Scheme with Colon Only

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

A string starting with a scheme and colon but lacking characters after the colon is not a valid autolink.

```markdown
<m:abc>
.
<p>&lt;m:abc&gt;</p>
```

--------------------------------

### Escaped Characters as Regular Characters

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Provides examples of escaped characters that lose their special Markdown meaning.

```markdown
\*not emphasized*
\<br/> not a tag
\[not a link](/foo)
\`not code`
1\. not a list
\* not a list
\# not a heading
\[foo]: /url "not a reference"
\&ouml; not a character entity
```

--------------------------------

### Run Standard Library Specifications

Source: https://github.com/crystal-lang/crystal/blob/master/CONTRIBUTING.md

Execute 'make std_spec' to run all specifications for the standard library. For a specific spec file, use 'bin/crystal spec <path_to_spec>'.

```shell
make std_spec
```

```shell
bin/crystal spec spec/std/array_spec.cr
```

--------------------------------

### HTML Block: Inline Tag with Attributes

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example of an HTML block using an inline tag with attributes.

```html
<i class="foo">
*bar*
</i>
.
```

--------------------------------

### Compile and Run a Crystal Program with 'run' command

Source: https://github.com/crystal-lang/crystal/blob/master/doc/man/crystal.adoc

An alternative method to compile and run a Crystal program using the 'run' command. This is useful for quick execution without creating a separate executable.

```shell
crystal run some_program.cr
```

--------------------------------

### Download libyaml

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads the libyaml library, a YAML parser and emitter. This snippet only downloads the library; building instructions are not included.

```powershell
# Download libyaml
iwr https://github.com/yaml/libyaml/archive/0.2.4.zip -OutFile libyaml.zip
Expand-Archive libyaml.zip -DestinationPath .
mv libyaml* libyaml
```

--------------------------------

### Download and Extract libz

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads and extracts the zlib library from a GitHub release using PowerShell.

```powershell
iwr https://github.com/madler/zlib/archive/v1.2.11.zip -OutFile zlib.zip
Expand-Archive zlib.zip -DestinationPath .
mv zlib* zlib
```

--------------------------------

### Uppercase URI Autolink

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates that URI schemes in autolinks are case-insensitive. This example uses an uppercase MAILTO scheme.

```markdown
<MAILTO:FOO@BAR.BAZ>
.
<p><a href="MAILTO:FOO@BAR.BAZ">MAILTO:FOO@BAR.BAZ</a></p>
```

--------------------------------

### Basic Unordered List

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a simple unordered list structure.

```markdown
- foo

notcode

- foo
```

--------------------------------

### Strong Emphasis with Literal Underscores

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Examples of strong emphasis containing literal underscores, including escaped ones.

```markdown
foo ___
```

```markdown
foo _\__
```

--------------------------------

### Build an Optimized Executable Crystal Program

Source: https://github.com/crystal-lang/crystal/blob/master/doc/man/crystal.adoc

Compile a Crystal program into an executable with optimizations enabled using the '--release' flag. This is recommended for production-ready executables and benchmarks.

```shell
crystal build --release some_program.cr
```

--------------------------------

### Basic Emphasis and Strong Emphasis

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates basic usage of emphasis and strong emphasis.

```markdown
foo***bar***baz
```

```markdown
foo******bar*********baz
```

--------------------------------

### Incorrect Nested List Indentation

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an example of incorrect indentation for nested lists, where sublists are not properly indented.

```markdown
- foo
 - bar
  - baz
   - boo
```

```html
<ul>
<li>foo</li>
<li>bar</li>
<li>baz</li>
<li>boo</li>
</ul>
```

--------------------------------

### Running Markdown Spec Tests

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Use this command to run conformance tests against a Markdown program using the spec.txt file.

```shell
python test/spec_tests.py --spec spec.txt --program PROGRAM
```

--------------------------------

### Download and Build libpcre

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Downloads and builds the PCRE library, used for regular expressions. Configures it for Unicode properties and JIT support.

```powershell
# Download libpcre
iwr https://cs.stanford.edu/pub/exim/pcre/pcre-8.43.zip -OutFile pcre.zip
Expand-Archive pcre.zip -DestinationPath .
mv pcre* pcre

# Build libpcre
cd pcre
cmake . -DBUILD_SHARED_LIBS=OFF -DPCRE_SUPPORT_UNICODE_PROPERTIES=ON -DPCRE_SUPPORT_JIT=ON -DPCRE_STATIC_RUNTIME=ON
cmake --build . --config Release
cd ..

mv pcre\Release\pcre.lib .

```

--------------------------------

### Code Span vs. Autolink Precedence

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

This example is parsed as code because the URL contains a backtick, preventing it from being recognized as an autolink.

```markdown
```````````````````````````````` example
`<http://foo.bar.`baz>`
.
```

--------------------------------

### Clone Crystal and Build Natively on Windows

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows

Clone the Crystal repository and build a native development compiler using the Windows-specific Makefile. Ensure core.autocrlf is set to false during cloning to prevent line ending issues.

```bash
git clone -c core.autocrlf=false https://github.com/crystal-lang/crystal.git
cd crystal
make -fMakefile.win crystal format release=1
```

--------------------------------

### Undefined Entity Reference Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows that entity references not on the HTML5 named entities list are treated as literal text.

```html
&MadeUpEntity;
.
```

```html
<p>&amp;MadeUpEntity;</p>
```

--------------------------------

### Link Reference Definition with Omitted Title

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Example of a link reference definition where the title is omitted, but the URL is still present.

```markdown
[foo]:
/url
```

--------------------------------

### Basic Fenced Code Block with Tildes

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a simple fenced code block using tildes. The info string specifies the language.

```markdown
~~~
<
 >
~~~
```

--------------------------------

### HTML Comment Block (Type 2)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Example of an HTML comment block, including multi-line comments. These are treated as HTML.

```markdown
<!-- Foo

bar
   baz -->
okay.
<!-- Foo

bar
   baz -->
<p>okay</p>
```

--------------------------------

### HTML Block: Tag Not in Block-Level List

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows how to start an HTML block with a tag not in the standard block-level list by placing it on its own line.

```html
<a href="foo">
*bar*
</a>
.
```

--------------------------------

### Build crystal.obj for Windows Cross-Compilation

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows

Use this command to build the crystal.obj file on a non-Windows host for Windows cross-compilation. Ensure CRYSTAL_LIBRARY_PATH includes the 'lib' directory from a Windows Crystal package.

```bash
CRYSTAL_LIBRARY_PATH=... make target=x86_64-windows-msvc FLAGS=-Dpreview_dll
```

--------------------------------

### Crystal Equivalent to Ruby's pack/unpack using IO

Source: https://github.com/crystal-lang/crystal/wiki/FAQ

Shows how to serialize an array of numbers into a string using Crystal's IO module, similar to Ruby's `Array#pack`.

```crystal
n = [65, 66, 67]

# Ruby
# n.pack("ccc") #=> "ABC"

# Crystal
String.build do |io|
  n.each do |number|
    io.write_byte number.to_u8
  end
end #=> "ABC"
```

--------------------------------

### Build Crystal Compiler on Windows using Windows Crystal

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Builds the Crystal compiler on Windows using a previously compiled Windows Crystal executable. This is part of the bootstrapping process.

```cmd
set LLVM_CONFIG=C:\crystal\llvm\Release\bin\llvm-config.exe
crystal.exe build src/compiler/crystal.cr -Di_know_what_im_doing -Dwithout_playground --link-flags=/STACK:10000000 -ocrystal2
crystal2.exe build src/compiler/crystal.cr -Di_know_what_im_doing -Dwithout_playground --link-flags=/STACK:10000000 -ocrystal3
```

--------------------------------

### Basic Variable Assignment in Crystal

Source: https://github.com/crystal-lang/crystal/blob/master/src/compiler/crystal/tools/playground/views/_about.html

Demonstrates simple variable assignment and how values are displayed in the playground's side panel.

```crystal
a = 1
b = 3
```

--------------------------------

### List Item Paragraph Wrapping Ambiguity

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows examples of lists where the rules for wrapping list items in <p> tags are ambiguous.

```markdown
1. one

2. two
3. three

```

```markdown
1.  one
    - a

    - b
2.  two

```

--------------------------------

### Invalid Autolink: Space in URI

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an example where spaces within angle brackets prevent autolink parsing. It is rendered as literal text.

```markdown
<http://foo.bar/baz bim>
.
<p>&lt;http://foo.bar/baz bim&gt;</p>
```

--------------------------------

### Image with Unescaped Brackets in Label

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

An example showing that link labels in Markdown images cannot contain unescaped brackets. This results in literal rendering.

```markdown
![[foo]]

[[foo]]: /url "title"
```

```html
<p>![[foo]]</p>
<p>[[foo]]: /url &quot;title&quot;</p>
```

--------------------------------

### Basic Emphasis with Underscores

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates simple emphasis using single underscores. Ensure delimiters do not match evenly to avoid unexpected behavior.

```markdown
foo _*_
.
<p>foo <em>*</em></p>
```

```markdown
foo _____ 
.
<p>foo _____</p>
```

```markdown
foo __\___ 
.
<p>foo <strong>_</strong></p>
```

```markdown
foo __*__ 
.
<p>foo <strong>*</strong></p>
```

```markdown
__foo_ 
.
<p>_<em>foo</em></p>
```

--------------------------------

### Compile and Run a Crystal Program

Source: https://github.com/crystal-lang/crystal/blob/master/doc/man/crystal.adoc

Use this command to compile and immediately run a Crystal source file. The source file typically ends with the .cr extension.

```shell
crystal some_program.cr
```

--------------------------------

### Invalid Pointy Bracket Matching

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Examples showing incorrect matching of pointy brackets in link destinations, which results in the text not being rendered as a link.

```markdown
[a](<b)c
```

```markdown
[a](<b)c>
```

```markdown
[a](<b>c)
```

```html
<p>[a](&lt;b)c
[a](&lt;b)c&gt;
[a](&lt;b&gt;c)</p>
```

--------------------------------

### Code Span Precedence over Emphasis

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Code spans have higher precedence than emphasis. The second asterisk in this example is part of the code span, not emphasis.

```markdown
```````````````````````````````` example
*foo`*`
.
```

--------------------------------

### Entity Reference Without Semicolon Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates that HTML entity references without a trailing semicolon (like &copy) are not recognized in CommonMark.

```html
&copy
.
```

```html
<p>&amp;copy</p>
```

--------------------------------

### Convert CMD to PowerShell

Source: https://github.com/crystal-lang/crystal/wiki/Porting-to-Windows-(old)

Allows switching from a Command Prompt session to a PowerShell session after setting up the environment.

```powershell
powershell
```

--------------------------------

### Nested Tight List

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a nested tight list structure.

```markdown
- a
  - b
```

--------------------------------

### Precedence of Full and Compact References

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows that full and compact reference links take precedence over shortcut references.

```markdown
[foo][bar]

[foo]: /url1
[bar]: /url2
.
<p><a href="/url2">foo</a></p>
```

```markdown
[foo][]

[foo]: /url1
.
<p><a href="/url1">foo</a></p>
```

--------------------------------

### Shortcut Reference Link with Inline Formatting

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates a shortcut reference link where the link text contains inline formatting.

```markdown
[*foo* bar]

[*foo* bar]: /url "title"
.
<p><a href="/url" title="title"><em>foo</em> bar</a></p>
```

--------------------------------

### HTML Entity References Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates the use of various HTML entity references for special characters. These are recognized outside of code blocks and spans.

```html
&nbsp; &amp; &copy; &AElig; &Dcaron;
&frac34; &HilbertSpace; &DifferentialD;
&ClockwiseContourIntegral; &ngE;
.
```

```html
<p>  &amp; © Æ Ď
¾ ℋ ⅆ
∲ ≧̸</p>
```

--------------------------------

### HTML Table with Inner Tags

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates an HTML table structure. This example highlights potential issues when inner tags are indented, which can affect parsing.

```markdown
<table>

<tr>

<td>
Hi
</td>

</tr>

</table>.
<table>
<tr>
<td>
Hi
</td>
</tr>
</table>
```

--------------------------------

### Markdown Link Reference Definitions

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates defining and using link references in Markdown. Ensure definitions precede their usage.

```markdown
[foo]: /url
bar
===
[foo]
.
<h1>bar</h1>
<p><a href="/url">foo</a></p>
```

```markdown
[foo]: /url
===
[foo]
.
<p>===
<a href="/url">foo</a></p>
```

```markdown
[foo]: /foo-url "foo"
[bar]: /bar-url
  "bar"
[baz]: /baz-url

[foo],
[bar],
[baz]
.
<p><a href="/foo-url" title="foo">foo</a>,
<a href="/bar-url" title="bar">bar</a>,
<a href="/baz-url">baz</a></p>
```

```markdown
[foo]

> [foo]: /url
.
<p><a href="/url">foo</a></p>
<blockquote>
</blockquote>
```

```markdown
[foo]: /url
.

```

--------------------------------

### Shortcut Reference Link

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Explains the shortcut reference link syntax, where the link text is enclosed in brackets and matches a reference definition.

```markdown
[foo]

[foo]: /url "title"
.
<p><a href="/url" title="title">foo</a></p>
```

--------------------------------

### HTML Block with Div and Markdown

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows an HTML block starting with '<DIV>' which contains Markdown content. The block is terminated by a blank line, and the Markdown is then parsed.

```markdown
<DIV CLASS="foo">

*Markdown*

</DIV>
.
<DIV CLASS="foo">
<p><em>Markdown</em></p>
</DIV>
```

--------------------------------

### Four-Space Rule Example (Markdown)

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Illustrates the four-space rule where subsequent paragraphs and sublists under a list item are indented by four spaces. This is contrasted with expected parsing.

```markdown
- foo

  bar

  - baz
```

--------------------------------

### Basic Reference Link

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a basic reference link where the label is enclosed in square brackets and followed by a reference definition.

```markdown
[ref\[]]: /uri
.
<p><a href="/uri">foo</a></p>
```

--------------------------------

### Unintended List Capture Example

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Demonstrates a case where a numeral followed by a period might be unintentionally parsed as a list item, even though it's part of a paragraph.

```markdown
The number of windows in my house is
1.  The number of doors is 6.
```

```html
<p>The number of windows in my house is</p>
<ol>
<li>The number of doors is 6.</li>
</ol>
```

--------------------------------

### Markdown Empty Bullet List Item

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Example of an empty bullet list item within a list. An empty list item is represented by a marker followed by a newline.

```markdown
- foo
- 
- bar
```

```html
<ul>
<li>foo</li>
<li></li>
<li>bar</li>
</ul>
```

--------------------------------

### Generating and Collecting Values in Loops (Crystal)

Source: https://github.com/crystal-lang/crystal/blob/master/src/compiler/crystal/tools/playground/views/_about.html

Illustrates how to collect values generated within a loop into an array. All produced values are aggregated and can be inspected in a table.

```crystal
def sample(n)
  res = [] of Float64
  n.times do
    res << rand
  end
  res
end

sample 5
```

--------------------------------

### List item with indented content after marker

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

This example shows a list item where content following the marker has an indent that is not a code block. The interpretation depends on subsequent lines.

```markdown
-    foo

  bar
```

--------------------------------

### Nested Unordered List

Source: https://github.com/crystal-lang/crystal/blob/master/lib/markd/spec/fixtures/spec.txt

Shows how to create nested unordered lists with varying indentation levels.

```markdown
- a
 - b
  - c
   - d
  - e
 - f
- g
```