haml--haml/lib/haml.rb

695 lines
18 KiB
Ruby

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# = Haml (XHTML Abstraction Markup Language)
#
# Haml is a markup language
# that's used to cleanly and simply describe the XHTML of any web document,
# without the use of inline code.
# Haml functions as a replacement
# for inline page templating systems such as PHP, RHTML, and ASP.
# However, Haml avoids the need for explicitly coding XHTML into the template,
# because it is actually an abstract description of the XHTML,
# with some code to generate dynamic content.
#
# == Features
#
# * Whitespace active
# * Well-formatted markup
# * DRY
# * Follows CSS conventions
# * Interpolates Ruby code
# * Implements Rails templates with the .haml extension
#
#
# == Characters with meaning to Haml
#
# Various characters, when placed at a certain point in a line,
# instruct Haml to render different types of things.
#
# === XHTML Tags
#
# These characters render XHTML tags.
#
# ==== %
#
#
# This element is placed at the beginning of a line.
# It's followed immediately by the name of an element,
# then optionally by modifiers (see below), a space,
# and text to be rendered inside the element.
# It creates an element in the form of <tt><element></element></tt>.
# For example:
#
# %one
# %two
# %three Hey there
#
# is compiled to:
#
# <one>
# <two>
# <three>Hey there</three>
# </two>
# </one>
#
# Any string is a valid element name;
# Haml will automatically generate opening and closing tags for any element.
#
# ==== {}
#
# Brackets represent a Ruby hash
# that is used for specifying the attributes of an element.
# It is literally evaluated as a Ruby hash,
# so logic will work in it and local variables may be used.
# Quote characters within the attribute
# will be replaced by appropriate escape sequences.
# The hash is placed after the tag is defined.
# For example:
#
# %head{ :name => "doc_head" }
# %script{ 'type' => "text/" + "javascript",
# :src => "javascripts/script_#{2 + 7}" }
#
# is compiled to:
#
# <head name="doc_head">
# <script src='javascripts/script_9' type='text/javascript'>
# </script>
# </head>
#
# ==== []
#
# Square brackets follow a tag definition and contain a Ruby object
# that is used to set the class and id of that tag.
# The class is set to the object's class
# (transformed to use underlines rather than camel case)
# and the id is set to the object's class, followed by its id.
# Because the id of an object is normally an obscure implementation detail,
# this is most useful for elements that represent instances of Models.
# For example:
#
# # file: app/controllers/users_controller.rb
#
# def show
# @user = CrazyUser.find(15)
# end
#
# # file: app/views/users/show.haml
#
# %div[@user]
# %bar[290]/
# Hello!
#
# is compiled to:
#
# <div class="crazy_user" id="crazy_user_15">
# <bar class="fixnum" id="fixnum_581" />
# Hello!
# </div>
#
# This is based off of DHH's SimplyHelpful syntax,
# as presented at RailsConf Europe 2006.
#
# ==== /
#
# The forward slash character, when placed at the end of a tag definition,
# causes the tag to be self-closed.
# For example:
#
# %br/
# %meta{'http-equiv' => 'Content-Type', :content => 'text/html'}/
#
# is compiled to:
#
# <br />
# <meta http-equiv='Content-Type' content='text/html' />
#
# ==== . and #
#
# The period and pound sign are borrowed from CSS.
# They are used as shortcuts to specify the <tt>class</tt>
# and <tt>id</tt> attributes of an element, respectively.
# Multiple class names can be specified in a similar way to CSS,
# by chaining the class names together with periods.
# They are placed immediately after the tag and before an attributes hash.
# For example:
#
# %div#things
# %span#rice Chicken Fried
# %p.beans{ :food => 'true' } The magical fruit
# %h1.class.otherclass#id La La La
#
# is compiled to:
#
# <div id='things'>
# <span id='rice'>Chicken Fried</span>
# <p class='beans' food='true'>The magical fruit</p>
# <h1 class='class otherclass' id='id'>La La La</h1>
# </div>
#
# And,
#
# #content
# .articles
# .article.title
# Doogie Howser Comes Out
# .article.date
# 2006-11-05
# .article.entry
# Neil Patrick Harris would like to dispel any rumors that he is straight
#
# is compiled to:
#
# <div id="content">
# <div class="articles">
# <div class="article title">Doogie Howser Comes Out</div>
# <div class="article date">2006-11-05</div>
# <div class="article entry">
# Neil Patrick Harris would like to dispel any rumors that he is straight
# </div>
# </div>
# </div>
#
# ==== Implicit Div Elements
#
# Because the div element is used so often, it is the default element.
# If you only define a class and/or id using the <tt>.</tt> or <tt>#</tt> syntax,
# a div element is automatically used.
# For example:
#
# #collection
# .item
# .description What a cool item!
#
# is the same as:
#
# %div{:id => collection}
# %div{:class => 'item'}
# %div{:class => 'description'} What a cool item!
#
# and is compiled to:
#
# <div id='collection'>
# <div class='item'>Broken record album</div>
# <div class='description'>What a cool item!</div>
# </div>
#
# ==== = and ~
#
# <tt>=</tt> and <tt>~</tt> are placed at the end of a tag definition,
# after class, id, and attribute declarations.
# They're just shortcuts for inserting Ruby code into an element.
# They work the same as <tt>=</tt> and <tt>~</tt> without a tag;
# see below for documentation of those.
# However, if the result is short enough,
# it is displayed entirely on one line.
# For example:
#
# %p= "hello"
# %h1~ 1 + 2
#
# is not quite the same as:
#
# %p
# = "hello"
# %h1
# ~ 1 + 2
#
# It's compiled to:
#
# <p>hello</p>
# <h1>3</h1>
#
# === XHTML Helpers
#
# ==== No Special Character
#
# If no special character appears at the beginning of a line,
# the line is rendered as plain text.
# For example:
#
# %gee
# %whiz
# Wow this is cool!
#
# is compiled to:
#
# <gee>
# <whiz>
# Wow this is cool!
# </whiz>
# </gee>
#
# ==== !!!
#
# When describing XHTML documents with Haml,
# you can have a document type or XML prolog generated automatically
# by including the characters <tt>!!!</tt>.
# For example:
#
# !!! XML
# !!!
# %html
# %head
# %title Myspace
# %body
# %h1 I am the international space station
# %p Sign my guestbook
#
# is compiled to:
#
# <?xml version="1.0" encoding="utf-8" ?>
# <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
# <html>
# <head>
# <title>Myspace</title>
# </head>
# <body>
# <h1>I am the international space station</h1>
# <p>Sign my guestbook</p>
# </body>
# </html>
#
# You can also specify the version and type of XHTML after the <tt>!!!</tt>.
# XHTML 1.0 Strict, Transitional, and Frameset and XHTML 1.1 are supported.
# The default version is 1.0 and the default type is Transitional.
# For example:
#
# !!! 1.1
#
# is compiled to:
#
# <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
#
# and
#
# !!! Strict
#
# is compiled to:
#
# <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
#
# If you're not using the UTF-8 characterset for your document,
# you can specify which encoding should appear
# in the XML prolog in a similar way.
# For example:
#
# !!! XML iso-8859-1
#
# is compiled to:
#
# <?xml version="1.0" encoding="iso-8859-1" ?>
#
# ==== /
#
# The forward slash character, when placed at the beginning of a line,
# wraps all text after it in an HTML comment.
# For example:
#
# %billabong
# / This is the billabong element
# I like billabongs!
#
# is compiled to:
#
# <billabong>
# <!-- This is the billabong element -->
# I like billabongs!
# </billabong>
#
# The forward slash can also wrap indented sections of code. For example:
#
# /
# %p This doesn't render...
# %div
# %h1 Because it's commented out!
#
# is compiled to:
#
# <!--
# <p>This doesn't render...</p>
# <div>
# <h1>Because it's commented out!</h1>
# </div>
# -->
#
# You can also use Internet Explorer conditional comments
# (about)[http://www.quirksmode.org/css/condcom.html]
# by enclosing the condition in square brackets after the <tt>/</tt>.
# For example:
#
# /[if IE]
# %a{ :href => 'http://www.mozilla.com/en-US/firefox/' }
# %h1 Get Firefox
#
# is compiled to:
#
# <!--[if IE]>
# <a href='http://www.mozilla.com/en-US/firefox/'>
# <h1>Get Firefox</h1>
# </a>
# <![endif]-->
#
# ==== \
#
# The backslash character escapes the first character of a line,
# allowing use of otherwise interpreted characters as plain text.
# For example:
#
# %title
# = @title
# \- MySite
#
# is compiled to:
#
# <title>
# MyPage
# - MySite
# </title>
#
# ==== |
#
# The pipe character designates a multiline string.
# It's placed at the end of a line
# and means that all following lines that end with <tt>|</tt>
# will be evaluated as though they were on the same line.
# For example:
#
# %whoo
# %hoo I think this might get |
# pretty long so I should |
# probably make it |
# multiline so it doesn't |
# look awful. |
# %p This is short.
#
# is compiled to:
#
# %hoo I think this might get |
# pretty long so I should |
# probably make it |
# multiline so it doesn't |
# look awful. |
#
# ==== :
#
# The colon character designates a filter.
# This allows you to pass an indented block of text as input
# to another filtering program and add the result to the output of Haml.
# The syntax is simply a colon followed by the name of the filter.
# For example,
#
# %p
# :markdown
# Textile
# =======
#
# Hello, *World*
#
# is compiled to
#
# <p>
# <h1>Textile</h1>
#
# <p>Hello, <em>World</em></p>
# </p>
#
# Haml has the following filters defined:
#
# [plain] Does not parse the filtered text.
#
# [ruby] Parses the filtered text with the normal Ruby interpreter.
# All output sent to <tt>$stdout</tt>, like with +puts+,
# is output into the Haml document.
# Not available if the <tt>suppress_eval</tt> option is set to true.
#
# [erb] Parses the filtered text with ERB, like an RHTML template.
# Not available if the <tt>suppress_eval</tt> option is set to true.
# At the moment, this doesn't support access to variables
# defined by Ruby on Rails or Haml code.
#
# [sass] Parses the filtered text with Sass to produce CSS output.
#
# [redcloth] Parses the filtered text with RedCloth (http://whytheluckystiff.net/ruby/redcloth),
# which uses both Textile and Markdown syntax.
# Only works if RedCloth is installed.
#
# [textile] Parses the filtered text with Textile (http://www.textism.com/tools/textile).
# Only works if RedCloth is installed.
#
# [markdown] Parses the filtered text with Markdown (http://daringfireball.net/projects/markdown).
# Only works if RedCloth or BlueCloth (http://www.deveiate.org/projects/BlueCloth)
# is installed
# (BlueCloth takes precedence if both are installed).
#
# You can also define your own filters (see Setting Options, below).
#
# === Ruby evaluators
#
# ==== =
#
# The equals character is followed by Ruby code,
# which is evaluated and the output inserted into the document as plain text.
# For example:
#
# %p
# = ['hi', 'there', 'reader!'].join " "
# = "yo"
#
# is compiled to:
#
# <p>
# hi there reader!
# yo
# </p>
#
# ==== ~
#
# The tilde character works the same as the equals character,
# but the output is modified in such a way
# that newlines in whitespace-sensitive elements work properly.
# For example:
#
# %foo
# = "Woah <pre> this is \n</pre> crazy"
# %foo2
# ~ "Woah <pre> this is \n</pre> crazy"
#
# is compiled to:
#
# <foo>
# Woah <pre> this is
# </pre> crazy
# </foo>
# <foo2>
# Woah <pre> this is &#x000A;</pre> crazy
# </foo2>
#
# If the ~ character isn't followed by text,
# it doesn't evaluate Ruby at all.
# Instead, an indented section following it will be rendered
# in a whitespace-sensitive manner,
# using HTML encodings for newlines.
# For example:
#
# For example:
#
# .house
# %pre
# ~
# /^^^\
# |[] []|
# |_____|
#
# is compiled to:
#
# <div class="house">
# <pre>
# &#x000A; /^^^\&#x000A;|[] []|&#x000A;|_____|&#x000A;
# </pre>
# </div>
#
# ==== -
#
# The hyphen character makes the text following it into "silent script":
# Ruby script that is evaluated, but not output.
#
# <b>It is not recommended that you use this widely;
# almost all processing code and logic should be restricted
# to the Controller, the Helper, or partials.</b>
#
# For example:
#
# - foo = "hello"
# - foo << " there"
# - foo << " you!"
# %p= foo
#
# is compiled to:
#
# <p>
# hello there you!
# </p>
#
# ===== Blocks
#
# Ruby blocks, like XHTML tags, don't need to be explicitly closed in Haml.
# Rather, they're automatically closed, based on indentation.
# A block begins whenever the indentation is increased
# after a silent script command.
# It ends when the indentation decreases
# (as long as it's not an +else+ clause or something similar).
# For example:
#
# - (42...47).each do |i|
# %p= i
# %p See, I can count!
#
# is compiled to:
#
# <p>
# 42
# </p>
# <p>
# 43
# </p>
# <p>
# 44
# </p>
# <p>
# 45
# </p>
# <p>
# 46
# </p>
#
# Another example:
#
# %p
# - case 2
# - when 1
# = "1!"
# - when 2
# = "2?"
# - when 3
# = "3."
#
# is compiled to:
#
# <p>
# 2?
# </p>
#
# == Using Haml as a Rails plugin
#
# Write Rails templates with the .haml extension.
# For example:
#
# # file: app/views/movies/teen_wolf.haml
#
# %html
# %head
# %title= "Teen Wolf (1985)"
# %body
# #contents
# %h1 "A highschooler discovers that he is a werewolf"
# %ul.cast
# %li "Scott Howard"
# %li "Rupert 'Stiles' Stilinski"
# %li "Lisa 'Boof' Marconi"
# %li "Lewis"
#
# is compiled to:
#
# <html>
# <head>
# <title>Teen Wolf (1985)</title>
# </head>
# <body>
# <div id='contents'>
# <h1>A highschooler discovers that he is a werewolf</h1>
# <ul class='cast'>
# <li>Scott Howard</li>
# <li>Rupert 'Stiles' Stilinski</li>
# <li>Lisa 'Boof' Marconi</li>
# <li>Lewis</li>
# </ul>
# </div>
# </body>
# </html>
#
# You can access instance variables in Haml templates
# the same way you do in ERb templates.
# Helper methods are also available in Haml templates.
# For example:
#
# # file: app/controllers/movies_controller.rb
#
# class MoviesController < ApplicationController
# def index
# @title = "Teen Wolf"
# end
# end
#
# # file: app/views/movies/index.haml
#
# #content
# .title
# %h1= @title
# = link_to 'Home', home_url
#
# may be compiled to:
#
# <div id='content'>
# <div class='title'>
# <h1>Teen Wolf</h1>
# <a href='/'>Home</a>
# </div>
# </div>
#
# === Setting Options
#
# Options can be set by setting the hash <tt>Haml::Template.options</tt>
# from <tt>environment.rb</tt>.
# Available options are:
#
# [<tt>:suppress_eval</tt>] Whether or not attribute hashes and Ruby scripts
# designated by <tt>=</tt> or <tt>~</tt> should be
# evaluated. If this is true, said scripts are
# rendered as empty strings. Defaults to false.
#
# [<tt>:precompiled</tt>] A string containing a precompiled Haml template.
# If this is passed, <tt>template</tt> is ignored
# and no precompilation is done.
#
# [<tt>:attr_wrapper</tt>] The character that should wrap element attributes.
# This defaults to <tt>'</tt> (an apostrophe). Characters
# of this type within the attributes will be escaped
# (e.g. by replacing them with <tt>&apos;</tt>) if
# the character is an apostrophe or a quotation mark.
#
# [<tt>:filename</tt>] The name of the Haml file being parsed.
# This is only used as information when exceptions are raised.
# This is automatically assigned when working through ActionView,
# so it's really only useful for the user to assign
# when dealing with Haml programatically.
#
# [<tt>:filters</tt>] A hash of filters that can be applied to Haml code.
# The keys are the string names of the filters;
# the values are references to the classes of the filters.
# User-defined filters should always have lowercase keys,
# and should have:
# * An +initialize+ method that accepts one parameter,
# the text to be filtered.
# * A +render+ method that returns the result of the filtering.
#
# [<tt>:locals</tt>] The local variables that will be available within the
# template. For instance, if <tt>:locals</tt> is
# <tt>{ :foo => "bar" }</tt>, then within the template,
# <tt>= foo</tt> will produce <tt>bar</tt>.
#
module Haml; end
require 'haml/engine'