Module | Haml::Util |
In: |
lib/haml/util.rb
|
A module containing various useful functions.
RUBY_VERSION | = | ::RUBY_VERSION.split(".").map {|s| s.to_i} | An array of ints representing the Ruby version number. |
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
# File lib/haml/util.rb, line 207 207: def def_static_method(klass, name, args, *vars) 208: erb = vars.pop 209: powerset(vars).each do |set| 210: context = StaticConditionalContext.new(set).instance_eval {binding} 211: klass.class_eval("def \#{static_method_name(name, *vars.map {|v| set.include?(v)})}(\#{args.join(', ')})\n \#{ERB.new(erb).result(context)}\nend\n") 212: end 213: 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
# File lib/haml/util.rb, line 154 154: def enum_with_index(enum) 155: ruby1_8? ? enum.enum_with_index : enum.each_with_index 156: 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
# File lib/haml/util.rb, line 146 146: def has?(attr, klass, method) 147: klass.send("#{attr}s").include?(ruby1_8? ? method.to_s : method.to_sym) 148: end
Maps the key-value pairs of a hash according to a block. For example:
map_hash({:foo => "bar", :baz => "bang"}) {|k, v| [k.to_s, v.to_sym]} #=> {"foo" => :bar, "baz" => :bang}
@param hash [Hash] The hash to map @yield [key, value] A block in which the key-value pairs are transformed @yieldparam [key] The hash key @yieldparam [value] The hash value @yieldreturn [(Object, Object)] The new value for the `[key, value]` pair @return [Hash] The mapped hash @see map_keys @see map_vals
# File lib/haml/util.rb, line 81 81: def map_hash(hash, &block) 82: to_hash(hash.map(&block)) 83: end
Maps the keys in a hash according to a block. For example:
map_keys({:foo => "bar", :baz => "bang"}) {|k| k.to_s} #=> {"foo" => "bar", "baz" => "bang"}
@param hash [Hash] The hash to map @yield [key] A block in which the keys are transformed @yieldparam key [Object] The key that should be mapped @yieldreturn [Object] The new value for the key @return [Hash] The mapped hash @see map_vals @see map_hash
# File lib/haml/util.rb, line 46 46: def map_keys(hash) 47: to_hash(hash.map {|k, v| [yield(k), v]}) 48: end
Maps the values in a hash according to a block. For example:
map_values({:foo => "bar", :baz => "bang"}) {|v| v.to_sym} #=> {:foo => :bar, :baz => :bang}
@param hash [Hash] The hash to map @yield [value] A block in which the values are transformed @yieldparam value [Object] The value that should be mapped @yieldreturn [Object] The new value for the value @return [Hash] The mapped hash @see map_keys @see map_hash
# File lib/haml/util.rb, line 63 63: def map_vals(hash) 64: to_hash(hash.map {|k, v| [k, yield(v)]}) 65: end
Concatenates all strings that are adjacent in an array, while leaving other elements as they are. For example:
merge_adjacent_strings([1, "foo", "bar", 2, "baz"]) #=> [1, "foobar", 2, "baz"]
@param enum [Enumerable] @return [Array] The enumerable with strings merged
# File lib/haml/util.rb, line 114 114: def merge_adjacent_strings(enum) 115: e = enum.inject([]) do |a, e| 116: if e.is_a?(String) && a.last.is_a?(String) 117: a.last << e 118: else 119: a << e 120: end 121: a 122: end 123: end
Computes the powerset of the given array. This is the set of all subsets of the array. For 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 94 94: def powerset(arr) 95: arr.inject([Set.new].to_set) do |powerset, el| 96: new_powerset = Set.new 97: powerset.each do |subset| 98: new_powerset << subset 99: new_powerset << subset + [el] 100: end 101: new_powerset 102: end 103: end
Whether or not this is running under Ruby 1.8 or lower.
@return [Boolean]
# File lib/haml/util.rb, line 128 128: def ruby1_8? 129: Haml::Util::RUBY_VERSION[0] == 1 && Haml::Util::RUBY_VERSION[1] < 9 130: end
Returns the path of a file relative to the Haml root directory.
@param file [String] The filename relative to the Haml root @return [String] The filename relative to the the working directory
# File lib/haml/util.rb, line 17 17: def scope(file) 18: File.join(File.dirname(__FILE__), '..', '..', file) 19: 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 225 225: def static_method_name(name, *vars) 226: "#{name}_#{vars.map {|v| !!v}.join('_')}" 227: end
Converts an array of `[key, value]` pairs to a hash. For example:
to_hash([[:foo, "bar"], [:baz, "bang"]]) #=> {:foo => "bar", :baz => "bang"}
@param arr [Array<(Object, Object)>] An array of pairs @return [Hash] A hash
# File lib/haml/util.rb, line 29 29: def to_hash(arr) 30: arr.compact.inject({}) {|h, (k, v)| h[k] = v; h} 31: end