Module | Haml::Filters::Base |
In: |
lib/haml/filters.rb
|
The base module for Haml filters. User-defined filters should be modules including this module. The name of the filter is taken by downcasing the module name. For instance, if the module is named `FooBar`, the filter will be `:foobar`.
A user-defined filter should override either \{render} or {\compile}. \{render} is the most common. It takes a string, the filter source, and returns another string, the result of the filter. For example, the following will define a filter named `:sass`:
module Haml::Filters::Sass include Haml::Filters::Base def render(text) ::Sass::Engine.new(text).render end end
For details on overriding \{compile}, see its documentation.
Note that filters overriding \{render} automatically support `#{}` for interpolating Ruby code. Those overriding \{compile} will need to add such support manually if it‘s desired.
This method is automatically called when {Base} is included in a module. It automatically defines a filter with the downcased name of that module. For example, if the module is named `FooBar`, the filter will be `:foobar`.
@param base [Module, Class] The module that this is included in
# File lib/haml/filters.rb, line 44 44: def self.included(base) 45: Filters.defined[base.name.split("::").last.downcase] = base 46: base.extend(base) 47: end
This should be overridden when a filter needs to have access to the Haml evaluation context. Rather than applying a filter to a string at compile-time, \{compile} uses the {Haml::Precompiler} instance to compile the string to Ruby code that will be executed in the context of the active Haml template.
Warning: the {Haml::Precompiler} interface is neither well-documented nor guaranteed to be stable. If you want to make use of it, you‘ll probably need to look at the source code and should test your filter when upgrading to new Haml versions.
@param precompiler [Haml::Precompiler] The precompiler instance @param text [String] The text of the filter @raise [Haml::Error] if none of \{compile}, \{render}, and \{render_with_options} are overridden
# File lib/haml/filters.rb, line 96 96: def compile(precompiler, text) 97: resolve_lazy_requires 98: filter = self 99: precompiler.instance_eval do 100: if contains_interpolation?(text) 101: return if options[:suppress_eval] 102: 103: push_script "find_and_preserve(\#{filter.inspect}.render_with_options(\#{unescape_interpolation(text)}, _hamlout.options))\n" 104: return 105: end 106: 107: rendered = Haml::Helpers::find_and_preserve(filter.render_with_options(text, precompiler.options), precompiler.options[:preserve]) 108: 109: if !options[:ugly] 110: push_text(rendered.rstrip.gsub("\n", "\n#{' ' * @output_tabs}")) 111: else 112: push_text(rendered.rstrip) 113: end 114: end 115: end
Same as \{compile}, but requires the necessary files first. *This is used by {Haml::Engine} and is not intended to be overridden or used elsewhere.*
@see compile
# File lib/haml/filters.rb, line 78 78: def internal_compile(*args) 79: resolve_lazy_requires 80: compile(*args) 81: end
This becomes a class method of modules that include {Base}. It allows the module to specify one or more Ruby files that Haml should try to require when compiling the filter.
The first file specified is tried first, then the second, etc. If none are found, the compilation throws an exception.
For example:
module Haml::Filters::Markdown lazy_require 'rdiscount', 'peg_markdown', 'maruku', 'bluecloth' ... end
@param reqs [Array<String>] The requires to run
# File lib/haml/filters.rb, line 136 136: def lazy_require(*reqs) 137: @lazy_requires = reqs 138: end
Takes the source text that should be passed to the filter and returns the result of running the filter on that string.
This should be overridden in most individual filter modules to render text with the given filter. If \{compile} is overridden, however, \{render} doesn‘t need to be.
@param text [String] The source text for the filter to process @return [String] The filtered result @raise [Haml::Error] if it‘s not overridden
# File lib/haml/filters.rb, line 59 59: def render(text) 60: raise Error.new("#{self.inspect}#render not defined!") 61: end
Same as \{render}, but takes a {Haml::Engine} options hash as well. It‘s only safe to rely on options made available in {Haml::Engine#options_for_buffer}.
@see render @param text [String] The source text for the filter to process @return [String] The filtered result @raise [Haml::Error] if it or \{render} isn‘t overridden
# File lib/haml/filters.rb, line 70 70: def render_with_options(text, options) 71: render(text) 72: end