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<article>
<h2>Crystal mode</h2>
<form><textarea id="code" name="code">
# Features of Crystal
# - Ruby-inspired syntax.
# - Statically type-checked but without having to specify the type of variables or method arguments.
# - Be able to call C code by writing bindings to it in Crystal.
# - Have compile-time evaluation and generation of code, to avoid boilerplate code.
# - Compile to efficient native code.
# A very basic HTTP server
require "http/server"
server = HTTP::Server.new(8080) do |request|
HTTP::Response.ok "text/plain", "Hello world, got #{request.path}!"
end
puts "Listening on http://0.0.0.0:8080"
server.listen
module Foo
def initialize(@foo); end
abstract def abstract_method : String
@[AlwaysInline]
def with_foofoo
with Foo.new(self) yield
end
struct Foo
def initialize(@foo); end
def hello_world
@foo.abstract_method
end
end
end
class Bar
include Foo
@@foobar = 12345
def initialize(@bar)
super(@bar.not_nil! + 100)
end
macro alias_method(name, method)
def {{ name }}(*args)
{{ method }}(*args)
end
end
def a_method
"Hello, World"
end
alias_method abstract_method, a_method
macro def show_instance_vars : Nil
{% for var in @type.instance_vars %}
puts "@{{ var }} = #{ @{{ var }} }"
{% end %}
nil
end
end
class Baz < Bar; end
lib LibC
fun c_puts = "puts"(str : Char*) : Int
end
$baz = Baz.new(100)
$baz.show_instance_vars
$baz.with_foofoo do
LibC.c_puts hello_world
end
</textarea></form>
<script>
var editor = CodeMirror.fromTextArea(document.getElementById("code"), {
mode: "text/x-crystal",
matchBrackets: true,
indentUnit: 2
});
</script>
<p><strong>MIME types defined:</strong> <code>text/x-crystal</code>.</p>
</article>