From b274828831fec26cd8b3089ffef14cb96ce2de2f Mon Sep 17 00:00:00 2001 From: Matthew Hall Date: Thu, 16 Mar 2023 20:36:03 +1300 Subject: Second rewrite attempt, this one should work, monkaS --- src/__OLD_parcom/between.cr | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 src/__OLD_parcom/between.cr (limited to 'src/__OLD_parcom/between.cr') diff --git a/src/__OLD_parcom/between.cr b/src/__OLD_parcom/between.cr new file mode 100644 index 0000000..05519e4 --- /dev/null +++ b/src/__OLD_parcom/between.cr @@ -0,0 +1,37 @@ +require "./parser.cr" +require "./map.cr" +require "./exactly.cr" +require "./at_most.cr" + +module Parcom + # `Between` is a `Parser` that tries to parse with another parser a number + # of times within a specified range. The results of each successful parse + # are returned in an array. If the number of successful parses is out of + # the lower bound of the range, the parser fails. If the number of successful + # parses reaches thhe upper bound of the range, the parsing stops, even if it + # is possible to keep parsing. + class Between(T, V) < Parser(T, Array(V)) + @p : Map(T, {Array(V), Array(V)}, Array(V)) + + # Accepts the lower and upper bounds for the number of parsing attempts, + # as well as the parser to use. This method works the same way whether or + # not the larger value is passed first or second. If a negative int value + # is given for either parameter, it is treated as `0`. + # TODO: Overload to allow for Range objects. + def initialize(i : Int, j : Int, p : Parser(T, V)) + lower = i < j ? i : j + upper = (i - j).abs + @p = (Exactly.new(lower, p) + AtMost.new(upper, p)).map do |tup| + tup[0] + tup[1] + end + end + + # Tries to parse a numebr of times within the given range. + def parse(tokens : Tokens(T)) : Result(T, Array(V)) + @p.parse(tokens) + rescue ex : ParserFail + raise ParserFail.new("Between: #{ex.message}") + end + end +end + -- cgit v1.2.1