Module: Haml::Helpers

Extended by:
Helpers
Includes:
ActionViewExtensions, XssMods
Included in:
Buffer, Helpers
Defined in:
lib/haml/helpers.rb,
lib/haml/template.rb,
lib/haml/helpers/action_view_extensions.rb

Overview

This module contains various helpful methods to make it easier to do various tasks. 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.

Defined Under Namespace

Modules: ActionViewExtensions Classes: ErrorReturn

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ActionViewExtensions

#page_class, #with_raw_haml_concat

Class Method Details

.action_view? ⇒ Boolean

Returns Whether or not ActionView is loaded

Returns:

  • (Boolean) —

    Whether or not ActionView is loaded

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# File 'lib/haml/helpers.rb', line 56

def self.action_view?
  @@action_view_defined
end

Instance Method Details

#block_is_haml?(block) ⇒ Boolean

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

Parameters:

  • block (Proc) —

    A Ruby block

Returns:

  • (Boolean) —

    Whether or not block is defined directly in a Haml template

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# File 'lib/haml/helpers.rb', line 640

def block_is_haml?(block)
  eval('!!defined?(_hamlout)', block.binding)
end

#capture_haml(*args) {|args| ... }

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|
    %p= a

the local variable foo would be assigned to "<p>13</p>\n".

Parameters:

  • args (Array) —

    Arguments to pass into the block

Yields:

  • (args) —

    A block of Haml code that will be converted to a string

Yield Parameters:

  • args (Array) —

    args

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# File 'lib/haml/helpers.rb', line 373

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

    captured
  end
ensure
  haml_buffer.capture_position = nil
end

#escape_once(text) ⇒ String

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

Parameters:

  • text (String) —

    The string to sanitize

Returns:

  • (String) —

    The sanitized string

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# File 'lib/haml/helpers.rb', line 620

def escape_once(text)
  text = text.to_s
  text.gsub(HTML_ESCAPE_ONCE_REGEX, HTML_ESCAPE)
end

#find_and_preserve(input, tags = haml_buffer.options[:preserve]) #find_and_preserve(tags = haml_buffer.options[:preserve]) { ... }

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

Overloads:

  • #find_and_preserve(input, tags = haml_buffer.options[:preserve])

    Escapes newlines within a string.

    Parameters:

    • input (String) —

      The string within which to escape newlines

  • #find_and_preserve(tags = haml_buffer.options[:preserve]) { ... }

    Escapes newlines within a block of Haml code.

    Yields:

    • The block within which to escape newlines

Parameters:

  • tags (Array<String>) (defaults to: haml_buffer.options[:preserve]) —

    Tags that should have newlines escaped

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# File 'lib/haml/helpers.rb', line 111

def find_and_preserve(input = nil, tags = haml_buffer.options[:preserve], &block)
  return find_and_preserve(capture_haml(&block), input || tags) if block
  tags = tags.map { |tag| Regexp.escape(tag) }.join('|')
  re = /<(#{tags})([^>]*)>(.*?)(<\/\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

#haml_concat(text = "")

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

Parameters:

  • text (#to_s) (defaults to: "") —

    The text to output

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# File 'lib/haml/helpers.rb', line 396

def haml_concat(text = "")
  haml_internal_concat text
  ErrorReturn.new("haml_concat")
end

#haml_indent ⇒ String

Returns The indentation string for the current line

Returns:

  • (String) —

    The indentation string for the current line

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# File 'lib/haml/helpers.rb', line 427

def haml_indent
  '  ' * haml_buffer.tabulation
end

#haml_tag(name, *rest, attributes = {}) { ... } #haml_tag(name, text, *flags, attributes = {})

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>

Overloads:

  • #haml_tag(name, *rest, attributes = {}) { ... }

    Yields:

    • The block of Haml code within the tag

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

    Parameters:

    • text (#to_s) —

      The text within the tag

    • flags (Array<Symbol>) —

      Haml end-of-tag flags

Parameters:

  • name (#to_s) —

    The name of the tag

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# File 'lib/haml/helpers.rb', line 488

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::AttributeBuilder.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_internal_concat_raw "<#{name}#{attributes}#{' /' if haml_buffer.options[:format] == :xhtml}>"
    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}>"
  end_tag = "</#{name}>"
  if block.nil?
    text = text.to_s
    if text.include?("\n")
      haml_internal_concat_raw tag
      tab_up
      haml_internal_concat text
      tab_down
      haml_internal_concat_raw end_tag
    else
      haml_internal_concat_raw tag, false
      haml_internal_concat text, false, false
      haml_internal_concat_raw end_tag, true, false
    end
    return ret
  end

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

  if flags.include?(:<)
    haml_internal_concat_raw tag, false
    haml_internal_concat "#{capture_haml(&block).strip}", false, false
    haml_internal_concat_raw end_tag, true, false
    return ret
  end

  haml_internal_concat_raw tag
  tab_up
  block.call
  tab_down
  haml_internal_concat_raw end_tag

  ret
end

#haml_tag_if(condition, *tag)

Conditionally wrap a block in an element. If condition is true then this method renders the tag described by the arguments in tag (using #haml_tag) with the given block inside, otherwise it just renders the block.

For example,

- haml_tag_if important, '.important' do
  %p
    A (possibly) important paragraph.

will produce

<div class='important'>
  <p>
    A (possibly) important paragraph.
  </p>
</div>

if important is truthy, and just

<p>
  A (possibly) important paragraph.
</p>

otherwise.

Like #haml_tag, haml_tag_if outputs directly to the buffer and its return value should not be used. Use #capture_haml if you need to use its results as a string.

Parameters:

  • condition —

    The condition to test to determine whether to render the enclosing tag

  • tag —

    Definition of the enclosing tag. See #haml_tag for details (specifically the form that takes a block)

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# File 'lib/haml/helpers.rb', line 586

def haml_tag_if(condition, *tag)
  if condition
    haml_tag(*tag){ yield }
  else
    yield
  end
  ErrorReturn.new("haml_tag_if")
end

#html_attrs(lang = 'en-US') ⇒ {#to_s => String}

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'>

Parameters:

  • lang (String) (defaults to: 'en-US') —

    The value of xml:lang and lang

Returns:

  • ({#to_s => String}) —

    The attribute hash

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# File 'lib/haml/helpers.rb', line 228

def html_attrs(lang = 'en-US')
  if haml_buffer.options[:format] == :xhtml
    {:xmlns => "http://www.w3.org/1999/xhtml", 'xml:lang' => lang, :lang => lang}
  else
    {:lang => lang}
  end
end

#html_escape(text) ⇒ String

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”.

Parameters:

  • text (String) —

    The string to sanitize

Returns:

  • (String) —

    The sanitized string

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# File 'lib/haml/helpers.rb', line 609

def html_escape(text)
  ERB::Util.html_escape(text)
end

#init_haml_helpers

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"

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# File 'lib/haml/helpers.rb', line 76

def init_haml_helpers
  @haml_buffer = Haml::Buffer.new(haml_buffer, Options.new.for_buffer)
  nil
end

#is_haml? ⇒ Boolean

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.

Returns:

  • (Boolean) —

    Whether or not the current template is a Haml template

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# File 'lib/haml/helpers.rb', line 632

def is_haml?
  !@haml_buffer.nil? && @haml_buffer.active?
end

#list_of(enum, opts = {}) {|item| ... }

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|
  %h3= key.humanize
  %p= 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|
  %a{ 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)

Parameters:

  • enum (Enumerable) —

    The list of objects to iterate over

  • opts (Enumerable<#to_s,#to_s>) (defaults to: {}) —

    Each key/value pair will become an attribute pair for each list item element.

Yields:

  • (item) —

    A block which contains Haml code that goes within list items

Yield Parameters:

  • item —

    An element of enum

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# File 'lib/haml/helpers.rb', line 200

def list_of(enum, opts={}, &block)
  opts_attributes = opts.map { |k, v| " #{k}='#{v}'" }.join
  enum.map do |i|
    result = capture_haml(i, &block)

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

    %Q!<li#{opts_attributes}>#{result}</li>!
  end.join("\n")
end

#non_haml { ... }

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.

Yields:

  • A block which won’t register as Haml

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# File 'lib/haml/helpers.rb', line 90

def non_haml
  was_active = @haml_buffer.active?
  @haml_buffer.active = false
  yield
ensure
  @haml_buffer.active = was_active
end

#precede(str) { ... }

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>

Parameters:

  • str (String) —

    The string to add before the Haml

Yields:

  • A block of Haml to prepend to

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# File 'lib/haml/helpers.rb', line 336

def precede(str, &block)
  "#{str}#{capture_haml(&block).chomp}\n"
end

#preserve(input) #preserve { ... } Also known as: flatten

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.

Overloads:

  • #preserve(input)

    Escapes newlines within a string.

    Parameters:

    • input (String) —

      The string within which to escape all newlines

  • #preserve { ... }

    Escapes newlines within a block of Haml code.

    Yields:

    • The block within which to escape newlines

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# File 'lib/haml/helpers.rb', line 133

def preserve(input = nil, &block)
  return preserve(capture_haml(&block)) if block
  s = input.to_s.chomp("\n")
  s.gsub!(/\n/, '&#x000A;')
  s.delete!("\r")
  s
end

#succeed(str) { ... }

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

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

Produces:

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

Parameters:

  • str (String) —

    The string to add after the Haml

Yields:

  • A block of Haml to append to

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# File 'lib/haml/helpers.rb', line 355

def succeed(str, &block)
  "#{capture_haml(&block).chomp}#{str}\n"
end

#surround(front, back = front) { ... }

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

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

Produces:

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

and

= surround '*' do
  %strong angry

Produces:

*<strong>angry</strong>*

Parameters:

  • front (String) —

    The string to add before the Haml

  • back (String) (defaults to: front) —

    The string to add after the Haml

Yields:

  • A block of Haml to surround

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# File 'lib/haml/helpers.rb', line 317

def surround(front, back = front, &block)
  output = capture_haml(&block)

  "#{front}#{output.chomp}#{back}\n"
end

#tab_down(i = 1)

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

Parameters:

  • i (Fixnum) (defaults to: 1) —

    The number of tabs by which to decrease the indentation

See Also:

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# File 'lib/haml/helpers.rb', line 263

def tab_down(i = 1)
  haml_buffer.tabulation -= i
end

#tab_up(i = 1)

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>

Parameters:

  • i (Fixnum) (defaults to: 1) —

    The number of tabs by which to increase the indentation

See Also:

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# File 'lib/haml/helpers.rb', line 254

def tab_up(i = 1)
  haml_buffer.tabulation += i
end

#with_tabs(i) { ... }

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>

Parameters:

  • i (Fixnum) —

    The number of tabs to use

Yields:

  • A block in which the indentation will be i spaces

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# File 'lib/haml/helpers.rb', line 286

def with_tabs(i)
  old_tabs = haml_buffer.tabulation
  haml_buffer.tabulation = i
  yield
ensure
  haml_buffer.tabulation = old_tabs
end