module Haml::Helpers

This module contains various helpful methods to make it easier to do various tasks. {Haml::Helpers} is automatically included in the context that a Haml template is parsed in, so all these methods are at your disposal from within the template.

Constants

HTML_ESCAPE

Characters that need to be escaped to HTML entities from user input

HTML_ESCAPE_ONCE_REGEX
HTML_ESCAPE_REGEX

Public Class Methods

action_view?() click to toggle source

@return [Boolean] Whether or not ActionView is loaded

# File lib/haml/helpers.rb, line 52
def self.action_view?
  @@action_view_defined
end

Public Instance Methods

block_is_haml?(block) click to toggle source

Returns whether or not `block` is defined directly in a Haml template.

@param block [Proc] A Ruby block @return [Boolean] Whether or not `block` is defined directly in a Haml template

# File lib/haml/helpers.rb, line 584
def block_is_haml?(block)
  eval('!!defined?(_hamlout)', block.binding)
end
capture_haml(*args, &block) click to toggle source

Captures the result of a block of Haml code, gets rid of the excess indentation, and returns it as a string. For example, after the following,

.foo
  - foo = capture_haml(13) do |a|
    %= a

the local variable `foo` would be assigned to `“<p>13</p>n”`.

@param args [Array] Arguments to pass into the block @yield [args] A block of Haml code that will be converted to a string @yieldparam args [Array] `args`

# File lib/haml/helpers.rb, line 362
def capture_haml(*args, &block)
  buffer = eval('if defined? _hamlout then _hamlout else nil end', block.binding) || haml_buffer
  with_haml_buffer(buffer) do
    position = haml_buffer.buffer.length

    haml_buffer.capture_position = position
    value = block.call(*args)

    captured = haml_buffer.buffer.slice!(position..-1)

    if captured == '' and value != haml_buffer.buffer
         captured = (value.is_a?(String) ? value : nil)
    end

    return nil if captured.nil?
    return (haml_buffer.options[:ugly] ? captured : prettify(captured))

  end
ensure
  haml_buffer.capture_position = nil
end
escape_once(text) click to toggle source

Escapes HTML entities in `text`, but without escaping an ampersand that is already part of an escaped entity.

@param text [String] The string to sanitize @return [String] The sanitized string

# File lib/haml/helpers.rb, line 558
def escape_once(text)
  text = text.to_s
  text.gsub(HTML_ESCAPE_ONCE_REGEX, HTML_ESCAPE)
end
find_and_preserve(input = nil, tags = haml_buffer.options[:preserve], &block) click to toggle source

Uses {#preserve} to convert any newlines inside whitespace-sensitive tags into the HTML entities for endlines.

@param tags [Array<String>] Tags that should have newlines escaped

@overload #find_and_preserve(input, tags = haml_buffer.options)

Escapes newlines within a string.

@param input [String] The string within which to escape newlines

@overload #find_and_preserve(tags = haml_buffer.options)

Escapes newlines within a block of Haml code.

@yield The block within which to escape newlines
# File lib/haml/helpers.rb, line 107
def find_and_preserve(input = nil, tags = haml_buffer.options[:preserve], &block)
  return find_and_preserve(capture_haml(&block), input || tags) if block
  re = /<(#{tags.map(&Regexp.method(:escape)).join('|')})([^>]*)>(.*?)(<\/\1>)/im
  input.to_s.gsub(re) do |s|
    s =~ re # Can't rely on $1, etc. existing since Rails' SafeBuffer#gsub is incompatible
    "<#{$1}#{$2}>#{preserve($3)}</#{$1}>"
  end
end
flatten(input = nil, &block)
Alias for: preserve
haml_concat(text = "") click to toggle source

Outputs text directly to the Haml buffer, with the proper indentation.

@param text [#to_s] The text to output

# File lib/haml/helpers.rb, line 387
def haml_concat(text = "")
  unless haml_buffer.options[:ugly] || haml_indent == 0
    haml_buffer.buffer << haml_indent <<
      text.to_s.gsub("\n", "\n" + haml_indent) << "\n"
  else
    haml_buffer.buffer << text.to_s << "\n"
  end
  ErrorReturn.new("haml_concat")
end
haml_indent() click to toggle source

@return [String] The indentation string for the current line

# File lib/haml/helpers.rb, line 398
def haml_indent
  '  ' * haml_buffer.tabulation
end
haml_tag(name, *rest, &block) click to toggle source

Creates an HTML tag with the given name and optionally text and attributes. Can take a block that will run between the opening and closing tags. If the block is a Haml block or outputs text using {#haml_concat}, the text will be properly indented.

`name` can be a string using the standard Haml class/id shorthand (e.g. “span#foo.bar”, “#foo”). Just like standard Haml tags, these class and id values will be merged with manually-specified attributes.

`flags` is a list of symbol flags like those that can be put at the end of a Haml tag (`:/`, `:<`, and `:>`). Currently, only `:/` and `:<` are supported.

`haml_tag` outputs directly to the buffer; its return value should not be used. If you need to get the results as a string, use {#capture_haml}.

For example,

haml_tag :table do
  haml_tag :tr do
    haml_tag 'td.cell' do
      haml_tag :strong, "strong!"
      haml_concat "data"
    end
    haml_tag :td do
      haml_concat "more_data"
    end
  end
end

outputs

<table>
  <tr>
    <td class='cell'>
      <strong>
        strong!
      </strong>
      data
    </td>
    <td>
      more_data
    </td>
  </tr>
</table>

@param name [#to_s] The name of the tag

@overload #haml_tag(name, *rest, attributes = {})

@yield The block of Haml code within the tag

@overload #haml_tag(name, text, *flags, attributes = {})

@param text [#to_s] The text within the tag
@param flags [Array<Symbol>] Haml end-of-tag flags
# File lib/haml/helpers.rb, line 459
def haml_tag(name, *rest, &block)
  ret = ErrorReturn.new("haml_tag")

  text = rest.shift.to_s unless [Symbol, Hash, NilClass].any? {|t| rest.first.is_a? t}
  flags = []
  flags << rest.shift while rest.first.is_a? Symbol
  attrs = (rest.shift || {})
  attrs.keys.each {|key| attrs[key.to_s] = attrs.delete(key)} unless attrs.empty?
  name, attrs = merge_name_and_attributes(name.to_s, attrs)

  attributes = Haml::Compiler.build_attributes(haml_buffer.html?,
    haml_buffer.options[:attr_wrapper],
    haml_buffer.options[:escape_attrs],
    haml_buffer.options[:hyphenate_data_attrs],
    attrs)

  if text.nil? && block.nil? && (haml_buffer.options[:autoclose].include?(name) || flags.include?(:/))
    haml_concat "<#{name}#{attributes} />"
    return ret
  end

  if flags.include?(:/)
    raise Error.new(Error.message(:self_closing_content)) if text
    raise Error.new(Error.message(:illegal_nesting_self_closing)) if block
  end

  tag = "<#{name}#{attributes}>"
  if block.nil?
    text = text.to_s
    if text.include?("\n")
      haml_concat tag
      tab_up
      haml_concat text
      tab_down
      haml_concat "</#{name}>"
    else
      tag << text << "</#{name}>"
      haml_concat tag
    end
    return ret
  end

  if text
    raise Error.new(Error.message(:illegal_nesting_line, name))
  end

  if flags.include?(:<)
    tag << capture_haml(&block).strip << "</#{name}>"
    haml_concat tag
    return ret
  end

  haml_concat tag
  tab_up
  block.call
  tab_down
  haml_concat "</#{name}>"

  ret
end
html_attrs(lang = 'en-US') click to toggle source

Returns a hash containing default assignments for the `xmlns`, `lang`, and `xml:lang` attributes of the `html` HTML element. For example,

%html{html_attrs}

becomes

<html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en-US' lang='en-US'>

@param lang [String] The value of `xml:lang` and `lang` @return [{#to_s => String}] The attribute hash

# File lib/haml/helpers.rb, line 221
def html_attrs(lang = 'en-US')
  {:xmlns => "http://www.w3.org/1999/xhtml", 'xml:lang' => lang, :lang => lang}
end
html_escape(text) click to toggle source

Returns a copy of `text` with ampersands, angle brackets and quotes escaped into HTML entities.

Note that if ActionView is loaded and XSS protection is enabled (as is the default for Rails 3.0+, and optional for version 2.3.5+), this won't escape text declared as “safe”.

@param text [String] The string to sanitize @return [String] The sanitized string

# File lib/haml/helpers.rb, line 537
def html_escape(text)
  text = text.to_s
  text.gsub(HTML_ESCAPE_REGEX, HTML_ESCAPE)
end
init_haml_helpers() click to toggle source

Note: this does *not* need to be called when using Haml helpers normally in Rails.

Initializes the current object as though it were in the same context as a normal ActionView instance using Haml. This is useful if you want to use the helpers in a context other than the normal setup with ActionView. For example:

context = Object.new
class << context
  include Haml::Helpers
end
context.init_haml_helpers
context.haml_tag :p, "Stuff"
# File lib/haml/helpers.rb, line 72
def init_haml_helpers
  @haml_buffer = Haml::Buffer.new(haml_buffer, Options.new.for_buffer)
  nil
end
is_haml?() click to toggle source

Returns whether or not the current template is a Haml template.

This function, unlike other {Haml::Helpers} functions, also works in other `ActionView` templates, where it will always return false.

@return [Boolean] Whether or not the current template is a Haml template

# File lib/haml/helpers.rb, line 576
def is_haml?
  !@haml_buffer.nil? && @haml_buffer.active?
end
list_of(enum, opts={}, &block) click to toggle source

Takes an `Enumerable` object and a block and iterates over the enum, yielding each element to a Haml block and putting the result into `<li>` elements. This creates a list of the results of the block. For example:

= list_of([['hello'], ['yall']]) do |i|
  = i[0]

Produces:

<li>hello</li>
<li>yall</li>

And:

= list_of({:title => 'All the stuff', :description => 'A book about all the stuff.'}) do |key, val|
  %3= key.humanize
  %= val

Produces:

<li>
  <h3>Title</h3>
  <p>All the stuff</p>
</li>
<li>
  <h3>Description</h3>
  <p>A book about all the stuff.</p>
</li>

While:

= list_of(["Home", "About", "Contact", "FAQ"], {class: "nav", role: "nav"}) do |item|
  %{ href="#" }= item

Produces:

   <li class='nav' role='nav'>
     <a href='#'>Home</a>
   </li>
   <li class='nav' role='nav'>
     <a href='#'>About</a>
   </li>
   <li class='nav' role='nav'>
     <a href='#'>Contact</a>
   </li>
   <li class='nav' role='nav'>
     <a href='#'>FAQ</a>
   </li>

`[[class", "nav"], [role", "nav"]]` could have been used instead of `{class: "nav", role: "nav"}` (or any enumerable collection where each pair of items responds to #to_s)

@param enum [Enumerable] The list of objects to iterate over @param [Enumerable<#to_s,#to_s>] opts Each key/value pair will become an attribute pair for each list item element. @yield [item] A block which contains Haml code that goes within list items @yieldparam item An element of `enum`

# File lib/haml/helpers.rb, line 192
def list_of(enum, opts={}, &block)
  opts_attributes = opts.empty? ? "" : " ".<<(opts.map{|k,v| "#{k}='#{v}'" }.join(" "))
  to_return = enum.collect do |i|
    result = capture_haml(i, &block)

    if result.count("\n") > 1
      result = result.gsub("\n", "\n  ")
      result = "\n  #{result.strip}\n"
    else
      result = result.strip
    end

    %Q<li#{opts_attributes}>#{result}</li>!
  end
  to_return.join("\n")
end
non_haml() { || ... } click to toggle source

Runs a block of code in a non-Haml context (i.e. {#is_haml?} will return false).

This is mainly useful for rendering sub-templates such as partials in a non-Haml language, particularly where helpers may behave differently when run from Haml.

Note that this is automatically applied to Rails partials.

@yield A block which won't register as Haml

# File lib/haml/helpers.rb, line 86
def non_haml
  was_active = @haml_buffer.active?
  @haml_buffer.active = false
  yield
ensure
  @haml_buffer.active = was_active
end
precede(str, &block) click to toggle source

Prepends a string to the beginning of a Haml block, with no whitespace between. For example:

= precede '*' do
  %span.small Not really

Produces:

*<span class='small'>Not really</span>

@param str [String] The string to add before the Haml @yield A block of Haml to prepend to

# File lib/haml/helpers.rb, line 325
def precede(str, &block)
  "#{str}#{capture_haml(&block).chomp}\n"
end
preserve(input = nil, &block) click to toggle source

Takes any string, finds all the newlines, and converts them to HTML entities so they'll render correctly in whitespace-sensitive tags without screwing up the indentation.

@overload perserve(input)

Escapes newlines within a string.

@param input [String] The string within which to escape all newlines

@overload perserve

Escapes newlines within a block of Haml code.

@yield The block within which to escape newlines
# File lib/haml/helpers.rb, line 128
def preserve(input = nil, &block)
  return preserve(capture_haml(&block)) if block
  input.to_s.chomp("\n").gsub(/\n/, '&#x000A;').gsub(/\r/, '')
end
Also aliased as: flatten
succeed(str, &block) click to toggle source

Appends a string to the end of a Haml block, with no whitespace between. For example:

click
= succeed '.' do
  %{:href=>"thing"} here

Produces:

click
<a href='thing'>here</a>.

@param str [String] The string to add after the Haml @yield A block of Haml to append to

# File lib/haml/helpers.rb, line 344
def succeed(str, &block)
  "#{capture_haml(&block).chomp}#{str}\n"
end
surround(front, back = front, &block) click to toggle source

Surrounds a block of Haml code with strings, with no whitespace in between. For example:

= surround '(', ')' do
  %{:href => "food"} chicken

Produces:

(<a href='food'>chicken</a>)

and

= surround '*' do
  %strong angry

Produces:

*<strong>angry</strong>*

@param front [String] The string to add before the Haml @param back [String] The string to add after the Haml @yield A block of Haml to surround

# File lib/haml/helpers.rb, line 306
def surround(front, back = front, &block)
  output = capture_haml(&block)

  "#{front}#{output.chomp}#{back}\n"
end
tab_down(i = 1) click to toggle source

Decrements the number of tabs the buffer automatically adds to the lines of the template.

@param i [Fixnum] The number of tabs by which to decrease the indentation @see tab_up

# File lib/haml/helpers.rb, line 252
def tab_down(i = 1)
  haml_buffer.tabulation -= i
end
tab_up(i = 1) click to toggle source

Increments the number of tabs the buffer automatically adds to the lines of the template. For example:

%h1 foo
- tab_up
%p bar
- tab_down
%strong baz

Produces:

<h1>foo</h1>
  <p>bar</p>
<strong>baz</strong>

@param i [Fixnum] The number of tabs by which to increase the indentation @see tab_down

# File lib/haml/helpers.rb, line 243
def tab_up(i = 1)
  haml_buffer.tabulation += i
end
with_tabs(i) { || ... } click to toggle source

Sets the number of tabs the buffer automatically adds to the lines of the template, but only for the duration of the block. For example:

%h1 foo
- with_tabs(2) do
  %p bar
%strong baz

Produces:

<h1>foo</h1>
    <p>bar</p>
<strong>baz</strong>

@param i [Fixnum] The number of tabs to use @yield A block in which the indentation will be `i` spaces

# File lib/haml/helpers.rb, line 275
def with_tabs(i)
  old_tabs = haml_buffer.tabulation
  haml_buffer.tabulation = i
  yield
ensure
  haml_buffer.tabulation = old_tabs
end

Private Instance Methods

haml_bind_proc(&proc) click to toggle source

Gives a proc the same local `_hamlout` and `_erbout` variables that the current template has.

@param proc [#call] The proc to bind @return [Proc] A new proc with the new variables bound

# File lib/haml/helpers.rb, line 627
def haml_bind_proc(&proc)
  _hamlout = haml_buffer
  #double assignment is to avoid warnings
  _erbout = _erbout = _hamlout.buffer
  proc { |*args| proc.call(*args) }
end
haml_buffer() click to toggle source

The current {Haml::Buffer} object.

@return [Haml::Buffer]

# File lib/haml/helpers.rb, line 618
def haml_buffer
  @haml_buffer if defined? @haml_buffer
end
merge_name_and_attributes(name, attributes_hash = {}) click to toggle source

Parses the tag name used for {#haml_tag} and merges it with the Ruby attributes hash.

# File lib/haml/helpers.rb, line 592
def merge_name_and_attributes(name, attributes_hash = {})
  # skip merging if no ids or classes found in name
  return name, attributes_hash unless name =~ /^(.+?)?([\.#].*)$/

  return $1 || "div", Buffer.merge_attrs(
    Haml::Parser.parse_class_and_id($2), attributes_hash)
end
prettify(text) click to toggle source
# File lib/haml/helpers.rb, line 634
def prettify(text)
  text = text.split(/^/)
  text.delete('')

  min_tabs = nil
  text.each do |line|
    tabs = line.index(/[^ ]/) || line.length
    min_tabs ||= tabs
    min_tabs = min_tabs > tabs ? tabs : min_tabs
  end

  text.map do |line|
    line.slice(min_tabs, line.length)
  end.join
end
with_haml_buffer(buffer) { || ... } click to toggle source

Runs a block of code with the given buffer as the currently active buffer.

@param buffer [Haml::Buffer] The Haml buffer to use temporarily @yield A block in which the given buffer should be used

# File lib/haml/helpers.rb, line 604
def with_haml_buffer(buffer)
  @haml_buffer, old_buffer = buffer, @haml_buffer
  old_buffer.active, old_was_active = false, old_buffer.active? if old_buffer
  @haml_buffer.active, was_active = true, @haml_buffer.active?
  yield
ensure
  @haml_buffer.active = was_active
  old_buffer.active = old_was_active if old_buffer
  @haml_buffer = old_buffer
end