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Contents
module Finitio
#
# The Relation type generator allows capturing sets of information facts,
# i.e. sets of tuples (of same heading). E.g.
#
# ColoredPoints = {{ point: Point, color: Color }}
#
# This class allows capturing relation types, in a way similar to TupleType:
#
# ColoredPoints = RelationType.new( Heading[...] )
#
# A ruby Set is used as concrete representation, and will contain hashes
# that are valid representations of the associated tuple type:
#
# R(ColoredPoints) = Set[ R({...}) ] = Set[Hash[...]]
#
# Accordingly, the dress transformation function has the signature below.
# It expects an Enumerable as input and fails if any duplicate is found
# (after tuple transformation), or if any tuple fails at being transformed.
#
# dress :: Alpha -> ColoredPoints throws TypeError
# dress :: Object -> Set[Hash[...]] throws TypeError
#
class RelationType < Type
include HeadingBasedType
include RelBasedType
def initialize(heading, name = nil, metadata = nil)
super
if heading.multi?
raise ArgumentError, "Multi heading forbidden"
end
end
def default_name
"{{#{heading.to_name}}}"
end
def suppremum(other)
super(other, RelationType, MultiRelationType)
end
end # class RelationType
end # module Finitio
Version data entries
9 entries across 9 versions & 1 rubygems