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-rw-r--r--lib/rake/task_arguments.rb74
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/rake/task_arguments.rb b/lib/rake/task_arguments.rb
new file mode 100644
index 00000000000..ab404d67f51
--- /dev/null
+++ b/lib/rake/task_arguments.rb
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+module Rake
+
+ ####################################################################
+ # TaskArguments manage the arguments passed to a task.
+ #
+ class TaskArguments
+ include Enumerable
+
+ attr_reader :names
+
+ # Create a TaskArgument object with a list of named arguments
+ # (given by :names) and a set of associated values (given by
+ # :values). :parent is the parent argument object.
+ def initialize(names, values, parent=nil)
+ @names = names
+ @parent = parent
+ @hash = {}
+ names.each_with_index { |name, i|
+ @hash[name.to_sym] = values[i] unless values[i].nil?
+ }
+ end
+
+ # Create a new argument scope using the prerequisite argument
+ # names.
+ def new_scope(names)
+ values = names.collect { |n| self[n] }
+ self.class.new(names, values, self)
+ end
+
+ # Find an argument value by name or index.
+ def [](index)
+ lookup(index.to_sym)
+ end
+
+ # Specify a hash of default values for task arguments. Use the
+ # defaults only if there is no specific value for the given
+ # argument.
+ def with_defaults(defaults)
+ @hash = defaults.merge(@hash)
+ end
+
+ def each(&block)
+ @hash.each(&block)
+ end
+
+ def method_missing(sym, *args, &block)
+ lookup(sym.to_sym)
+ end
+
+ def to_hash
+ @hash
+ end
+
+ def to_s
+ @hash.inspect
+ end
+
+ def inspect
+ to_s
+ end
+
+ protected
+
+ def lookup(name)
+ if @hash.has_key?(name)
+ @hash[name]
+ elsif @parent
+ @parent.lookup(name)
+ end
+ end
+ end
+
+ EMPTY_TASK_ARGS = TaskArguments.new([], [])
+end