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authorGiuseppe Bilotta <giuseppe.bilotta@gmail.com>2008-03-13 00:40:43 +0100
committerGiuseppe Bilotta <giuseppe.bilotta@gmail.com>2008-03-13 00:58:20 +0100
commit954344576db4a5b60c6bae1fa13eaa2946e427a8 (patch)
tree27a13d6123b7e1ac5064a3278b6664d541919199 /lib
parentf8904942be535a70d8d2fa1eec710b6564fc2817 (diff)
filters: initial implementation
Diffstat (limited to 'lib')
-rw-r--r--lib/rbot/core/utils/filters.rb80
1 files changed, 80 insertions, 0 deletions
diff --git a/lib/rbot/core/utils/filters.rb b/lib/rbot/core/utils/filters.rb
new file mode 100644
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+++ b/lib/rbot/core/utils/filters.rb
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+#-- vim:sw=2:et
+#++
+#
+# :title: Stream filters
+#
+# Author:: Giuseppe "Oblomov" Bilotta <giuseppe.bilotta@gmail.com>
+# Copyright:: (C) 2008 Giuseppe Bilotta
+# License:: GPL v2
+#
+# This file collects methods to handle 'stream filters', a generic mechanism
+# to transform text+attributes into other text+attributes
+
+module ::Irc
+ class Bot
+
+ # The DataStream class. A DataStream is just a Hash. The :text key has
+ # a special meaning because it's the value that will be used when
+ # converting to String
+ class DataStream < Hash
+
+ def initialize(hsh={})
+ self.replace(hsh)
+ end
+
+ # Returns the :text key
+ def to_s
+ return self[:text]
+ end
+ end
+
+ # The DataFilter class. A DataFilter is a wrapper around a block
+ # that can be run on a DataStream to process it. The block is supposed to
+ # return another DataStream object
+ class DataFilter
+ def initialize(&block)
+ raise "No block provided" unless block_given?
+ @block = block
+ end
+
+ def call(stream)
+ @block.call(stream)
+ end
+ alias :run :call
+ alias :filter :call
+ end
+
+ # This method processes the DataStream _stream_ with the filters _name_.
+ # _name_ can be either a single Symbol (filter name), or an Array of
+ # Symbols, in which case the output of each filter will be used as input
+ # for the next
+ #
+ def filter(name, stream={})
+ @filters ||= {}
+ names = (Symbol === name ? [name] : name.dup)
+ ds = (DataStream === stream ? stream : DataStream.new(stream))
+ return ds if names.empty?
+ # check if filters exist
+ missing = names - @filters.keys
+ raise "Missing filters: #{missing.join(', ')}" unless missing.empty?
+ fs = @filters.values_at(*names)
+ fs.inject(ds) { |mid, f| mid = f.call(mid) }
+ end
+
+ # This method is used to register a new filter
+ def register_filter(name, &block)
+ raise "No block provided" unless block_given?
+ @filters ||= {}
+ @filters[name.to_sym] = DataFilter.new &block
+ end
+
+ # This method clears the filter list and installs the identity filter
+ def clear_filters
+ @filters ||= {}
+ @filters.clear
+ register_filter(:identity) { |stream| stream }
+ end
+ end
+end
+
+