module Haml::Util
A module containing various useful functions.
Public Instance Methods
Returns an ActionView::Template* class. In pre-3.0 versions of Rails, most of these classes were of the form `ActionView::TemplateFoo`, while afterwards they were of the form `ActionView;:Template::Foo`.
@param name [#to_s] The name of the class to get.
For example, `:Error` will return `ActionView::TemplateError` or `ActionView::Template::Error`.
# File lib/haml/util.rb, line 65 def av_template_class(name) return ActionView.const_get("Template#{name}") if ActionView.const_defined?("Template#{name}") return ActionView::Template.const_get(name.to_s) end
Moves a scanner through a balanced pair of characters. For example:
Foo (Bar (Baz bang) bop) (Bang (bop bip)) ^ ^ from to
@param scanner [StringScanner] The string scanner to move @param start [Character] The character opening the balanced pair.
A `Fixnum` in 1.8, a `String` in 1.9
@param finish [Character] The character closing the balanced pair.
A `Fixnum` in 1.8, a `String` in 1.9
@param count [Fixnum] The number of opening characters matched
before calling this method
@return [(String, String)] The string matched within the balanced pair
and the rest of the string. `["Foo (Bar (Baz bang) bop)", " (Bang (bop bip))"]` in the example above.
# File lib/haml/util.rb, line 295 def balance(scanner, start, finish, count = 0) str = '' scanner = StringScanner.new(scanner) unless scanner.is_a? StringScanner regexp = Regexp.new("(.*?)[\\#{start.chr}\\#{finish.chr}]", Regexp::MULTILINE) while scanner.scan(regexp) str << scanner.matched count += 1 if scanner.matched[-1] == start count -= 1 if scanner.matched[-1] == finish return [str.strip, scanner.rest] if count == 0 end end
Returns information about the caller of the previous method.
@param entry [String] An entry in the `#caller` list, or a similarly formatted string @return [[String, Fixnum, (String, nil)]] An array containing the filename, line, and method name of the caller.
The method name may be nil
# File lib/haml/util.rb, line 39 def caller_info(entry = caller[1]) info = entry.scan(/^(.*?):(-?.*?)(?::.*`(.+)')?$/).first info[1] = info[1].to_i # This is added by Rubinius to designate a block, but we don't care about it. info[2].sub!(/ \{\}\Z/, '') if info[2] info end
# File lib/haml/util.rb, line 103 def check_encoding(str) str.gsub(/\A\xEF\xBB\xBF/, '') # Get rid of the UTF-8 BOM end
Like {#check_encoding}, but also checks for a Ruby-style `-# coding:` comment at the beginning of the template and uses that encoding if it exists.
The Haml encoding rules are simple. If a `-# coding:` comment exists, we assume that that's the original encoding of the document. Otherwise, we use whatever encoding Ruby has.
Haml uses the same rules for parsing coding comments as Ruby. This means that it can understand Emacs-style comments (e.g. `-*- encoding: “utf-8” -*-`), and also that it cannot understand non-ASCII-compatible encodings such as `UTF-16` and `UTF-32`.
@param str [String] The Haml template of which to check the encoding @yield [msg] A block in which an encoding error can be raised.
Only yields if there is an encoding error
@yieldparam msg [String] The error message to be raised @return [String] The original string encoded properly @raise [ArgumentError] if the document declares an unknown encoding
# File lib/haml/util.rb, line 154 def check_haml_encoding(str, &block) check_encoding(str, &block) end
# File lib/haml/util.rb, line 324 def contains_interpolation?(str) str.include?('#{') end
This is used for methods in {Haml::Buffer} that need to be very fast, and take a lot of boolean parameters that are known at compile-time. Instead of passing the parameters in normally, a separate method is defined for every possible combination of those parameters; these are then called using {#static_method_name}.
To define a static method, an ERB template for the method is provided. All conditionals based on the static parameters are done as embedded Ruby within this template. For example:
def_static_method(Foo, :my_static_method, [:foo, :bar], :baz, :bang, <<RUBY) <% if baz && bang %> return foo + bar <% elsif baz || bang %> return foo - bar <% else %> return 17 <% end %> RUBY
{#static_method_name} can be used to call static methods.
@overload #def_static_method(klass, name, args, *vars, erb) @param klass [Module] The class on which to define the static method @param name [#to_s] The (base) name of the static method @param args [Array<Symbol>] The names of the arguments to the defined methods
(**not** to the ERB template)
@param vars [Array<Symbol>] The names of the static boolean variables
to be made available to the ERB template
# File lib/haml/util.rb, line 238 def def_static_method(klass, name, args, *vars) erb = vars.pop info = caller_info powerset(vars).each do |set| context = StaticConditionalContext.new(set).instance_eval {binding} method_content = (defined?(Erubis::TinyEruby) && Erubis::TinyEruby || ERB).new(erb).result(context) klass.class_eval(" def #{static_method_name(name, *vars.map {|v| set.include?(v)})}(#{args.join(', ')}) #{method_content} end ", info[0], info[1]) end end
Scans through a string looking for the interoplation-opening `#{` and, when it's found, yields the scanner to the calling code so it can handle it properly.
The scanner will have any backslashes immediately in front of the `#{` as the second capture group (`scan`), and the text prior to that as the first (`scan`).
@yieldparam scan [StringScanner] The scanner scanning through the string @return [String] The text remaining in the scanner after all `#{`s have been processed
# File lib/haml/util.rb, line 272 def handle_interpolation(str) scan = StringScanner.new(str) yield scan while scan.scan(/(.*?)(\*)\#\{/) scan.rest end
Returns the given text, marked as being HTML-safe. With older versions of the Rails XSS-safety mechanism, this destructively modifies the HTML-safety of `text`.
@param text [String, nil] @return [String, nil] `text`, marked as HTML-safe
# File lib/haml/util.rb, line 87 def html_safe(text) return unless text text.html_safe end
Formats a string for use in error messages about indentation.
@param indentation [String] The string used for indentation @return [String] The name of the indentation (e.g. `“12 spaces”`, `“1 tab”`)
# File lib/haml/util.rb, line 311 def human_indentation(indentation) if !indentation.include?(?\t) noun = 'space' elsif !indentation.include?(?\s) noun = 'tab' else return indentation.inspect end singular = indentation.length == 1 "#{indentation.length} #{noun}#{'s' unless singular}" end
# File lib/haml/util.rb, line 171 def inspect_obj(obj) return obj.inspect end
Computes the powerset of the given array. This is the set of all subsets of the array.
@example
powerset([1, 2, 3]) #=> Set[Set[], Set[1], Set[2], Set[3], Set[1, 2], Set[2, 3], Set[1, 3], Set[1, 2, 3]]
@param arr [Enumerable] @return [Set<Set>] The subsets of `arr`
# File lib/haml/util.rb, line 23 def powerset(arr) arr.inject([Set.new].to_set) do |powerset, el| new_powerset = Set.new powerset.each do |subset| new_powerset << subset new_powerset << subset + [el] end new_powerset end end
# File lib/haml/template.rb, line 23 def rails_xss_safe?; true; end
Silence all output to STDERR within a block.
@yield A block in which no output will be printed to STDERR
# File lib/haml/util.rb, line 50 def silence_warnings the_real_stderr, $stderr = $stderr, StringIO.new yield ensure $stderr = the_real_stderr end
Computes the name for a method defined via {#def_static_method}.
@param name [String] The base name of the static method @param vars [Array<Boolean>] The static variable assignment @return [String] The real name of the static method
# File lib/haml/util.rb, line 258 def static_method_name(name, *vars) :"#{name}_#{vars.map {|v| !!v}.join('_')}" end
# File lib/haml/util.rb, line 328 def unescape_interpolation(str, escape_html = nil) res = '' rest = Haml::Util.handle_interpolation str.dump do |scan| escapes = (scan[2].size - 1) / 2 res << scan.matched[0...-3 - escapes] if escapes % 2 == 1 res << '#{' else content = eval('"' + balance(scan, ?{, ?}, 1)[0][0...-1] + '"') content = "Haml::Helpers.html_escape((#{content}))" if escape_html res << '#{' + content + "}"# Use eval to get rid of string escapes end end res + rest end
Private Instance Methods
Parses a magic comment at the beginning of a Haml file. The parsing rules are basically the same as Ruby's.
@return [(Boolean, String or nil)]
Whether the document begins with a UTF-8 BOM, and the declared encoding of the document (or nil if none is declared)
# File lib/haml/util.rb, line 352 def parse_haml_magic_comment(str) scanner = StringScanner.new(str.dup.force_encoding("BINARY")) bom = scanner.scan(/\xEF\xBB\xBF/n) return bom unless scanner.scan(/-\s*#\s*/n) if coding = try_parse_haml_emacs_magic_comment(scanner) return bom, coding end return bom unless scanner.scan(/.*?coding[=:]\s*([\w-]+)/in) return bom, scanner[1] end
# File lib/haml/util.rb, line 364 def try_parse_haml_emacs_magic_comment(scanner) pos = scanner.pos return unless scanner.scan(/.*?-\*-\s*/n) # From Ruby's parse.y return unless scanner.scan(/([^\s'":;]+)\s*:\s*("(?:\.|[^"])*"|[^"\s;]+?)[\s;]*-\*-/n) name, val = scanner[1], scanner[2] return unless name =~ /(en)?coding/in val = $1 if val =~ /^"(.*)"$/n return val ensure scanner.pos = pos end