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# helps model complex dice systems such as "count number of dice showing X or more"
class GamesDice::MapRule
# trigger_op, trigger_value, mapped_value and mapped_name set the attributes of the same name
# rule = RPGMapRule.new( 6, :<=, 1, 'Success' ) # score 1 for a result of 6 or more
def initialize trigger_value, trigger_op, mapped_value=0, mapped_name=''
if ! trigger_value.respond_to?( trigger_op )
raise ArgumentError, "trigger_value #{trigger_value.inspect} cannot respond to trigger_op #{trigger_value.inspect}"
end
@trigger_value = trigger_value
@trigger_op = trigger_op
raise TypeError if ! mapped_value.is_a? Numeric
@mapped_value = Integer(mapped_value)
@mapped_name = mapped_name.to_s
end
# an Integer value or Range that will be mapped to a single value. #trigger_op is called against it
attr_reader :trigger_value
# a valid symbol for a method, which will be called against #trigger_value with the current
# die result as a param. If the operator returns true for a specific die result, then the
# mapped_value will be used in its stead. If the operator returns nil or false, the map is not
# triggered. All other values will be returned as the result of the map (allowing you to
# specify any method that takes an integer as input and returns something else as the end result)
attr_reader :trigger_op
# an integer value
attr_reader :mapped_value
# a string description of the mapping, e.g. 'S' for a success
attr_reader :mapped_name
# runs the rule against test_value, returning either a new value, or nil if the rule does not apply
def map_from test_value
op_result = @trigger_value.send( @trigger_op, test_value )
return nil unless op_result
if op_result == true
return @mapped_value
end
return op_result
end
end # class MapRule
Version data entries
7 entries across 7 versions & 1 rubygems