util.rb

Path: lib/haml/util.rb
Last Update: Mon Jun 07 20:03:46 +0000 2010

Required files

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Methods

Public Instance methods

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

@param erb [String] The template for the method code

[Source]

     # File lib/haml/util.rb, line 680
680:     def def_static_method(klass, name, args, *vars)
681:       erb = vars.pop
682:       info = caller_info
683:       powerset(vars).each do |set|
684:         context = StaticConditionalContext.new(set).instance_eval {binding}
685:         klass.class_eval("def \#{static_method_name(name, *vars.map {|v| set.include?(v)})}(\#{args.join(', ')})\n  \#{ERB.new(erb).result(context)}\nend\n", info[0], info[1])
686:       end
687:     end

A version of `Enumerable#enum_cons` that works in Ruby 1.8 and 1.9.

@param enum [Enumerable] The enumerable to get the enumerator for @param n [Fixnum] The size of each cons @return [Enumerator] The consed enumerator

[Source]

     # File lib/haml/util.rb, line 576
576:     def enum_cons(enum, n)
577:       ruby1_8? ? enum.enum_cons(n) : enum.each_cons(n)
578:     end

A version of `Enumerable#enum_slice` that works in Ruby 1.8 and 1.9.

@param enum [Enumerable] The enumerable to get the enumerator for @param n [Fixnum] The size of each slice @return [Enumerator] The consed enumerator

[Source]

     # File lib/haml/util.rb, line 585
585:     def enum_slice(enum, n)
586:       ruby1_8? ? enum.enum_slice(n) : enum.each_slice(n)
587:     end

A version of `Enumerable#enum_with_index` that works in Ruby 1.8 and 1.9.

@param enum [Enumerable] The enumerable to get the enumerator for @return [Enumerator] The with-index enumerator

[Source]

     # File lib/haml/util.rb, line 567
567:     def enum_with_index(enum)
568:       ruby1_8? ? enum.enum_with_index : enum.each_with_index
569:     end

Flattens the first `n` nested arrays in a cross-version manner.

@param arr [Array] The array to flatten @param n [Fixnum] The number of levels to flatten @return [Array] The flattened array

[Source]

     # File lib/haml/util.rb, line 602
602:     def flatten(arr, n)
603:       return arr.flatten(n) unless ruby1_8_6?
604:       return arr if n == 0
605:       arr.inject([]) {|res, e| e.is_a?(Array) ? res.concat(flatten(e, n - 1)) : res << e}
606:     end

Checks to see if a class has a given method. For example:

    Haml::Util.has?(:public_instance_method, String, :gsub) #=> true

Method collections like `Class#instance_methods` return strings in Ruby 1.8 and symbols in Ruby 1.9 and on, so this handles checking for them in a compatible way.

@param attr [to_s] The (singular) name of the method-collection method

  (e.g. `:instance_methods`, `:private_methods`)

@param klass [Module] The class to check the methods of which to check @param method [String, Symbol] The name of the method do check for @return [Boolean] Whether or not the given collection has the given method

[Source]

     # File lib/haml/util.rb, line 559
559:     def has?(attr, klass, method)
560:       klass.send("#{attr}s").include?(ruby1_8? ? method.to_s : method.to_sym)
561:     end

Returns the ASCII code of the given character.

@param c [String] All characters but the first are ignored. @return [Fixnum] The ASCII code of `c`.

[Source]

     # File lib/haml/util.rb, line 593
593:     def ord(c)
594:       ruby1_8? ? c[0] : c.ord
595:     end

Tests the hash-equality of two sets in a cross-version manner. Aggravatingly, this is order-dependent in Ruby 1.8.6.

@param set1 [Set] @param set2 [Set] @return [Boolean] Whether or not the sets are hashcode equal

[Source]

     # File lib/haml/util.rb, line 624
624:     def set_eql?(set1, set2)
625:       return set1.eql?(set2) unless ruby1_8_6?
626:       set1.to_a.uniq.sort_by {|e| e.hash}.eql?(set2.to_a.uniq.sort_by {|e| e.hash})
627:     end

Returns the hash code for a set in a cross-version manner. Aggravatingly, this is order-dependent in Ruby 1.8.6.

@param set [Set] @return [Fixnum] The order-independent hashcode of `set`

[Source]

     # File lib/haml/util.rb, line 613
613:     def set_hash(set)
614:       return set.hash unless ruby1_8_6?
615:       set.map {|e| e.hash}.uniq.sort.hash
616:     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

[Source]

     # File lib/haml/util.rb, line 699
699:     def static_method_name(name, *vars)
700:       "#{name}_#{vars.map {|v| !!v}.join('_')}"
701:     end

[Validate]