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Versions: 6
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Stored size: 1.58 KB
Contents
module Mutant
class Expression
class Parser
include Concord.new(:types)
class ParserError < RuntimeError
include AbstractType
end # ParserError
# Error raised on invalid expressions
class InvalidExpressionError < ParserError; end
# Error raised on ambiguous expressions
class AmbiguousExpressionError < ParserError; end
# Parse input into expression or raise
#
# @param [String] syntax
#
# @return [Expression]
# if expression is valid
#
# @raise [ParserError]
# otherwise
def call(input)
try_parse(input) or fail InvalidExpressionError, "Expression: #{input.inspect} is not valid"
end
# Try to parse input into expression
#
# @param [String] input
#
# @return [Expression]
# if expression is valid
#
# @return [nil]
# otherwise
def try_parse(input)
expressions = expressions(input)
case expressions.length
when 0, 1
expressions.first
else
fail AmbiguousExpressionError, "Ambiguous expression: #{input.inspect}"
end
end
private
# Expressions parsed from input
#
# @param [String] input
#
# @return [Array<Expression>]
# if expressions can be parsed from input
def expressions(input)
types.each_with_object([]) do |type, aggregate|
expression = type.try_parse(input)
aggregate << expression if expression
end
end
end # Parser
end # Expression
end # Mutant
Version data entries
6 entries across 6 versions & 1 rubygems