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/some.cr | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 src/__OLD_parcom/some.cr (limited to 'src/__OLD_parcom/some.cr') diff --git a/src/__OLD_parcom/some.cr b/src/__OLD_parcom/some.cr new file mode 100644 index 0000000..a2e3563 --- /dev/null +++ b/src/__OLD_parcom/some.cr @@ -0,0 +1,33 @@ +require "./parser.cr" +require "./assert.cr" +require "./many.cr" + +module Parcom + # `Some` is a `Parser` that repeatedly tries to parse with another parser. + # The `Some` object will collect all success values in an array, and + # return them with the final state of the input stream. If the wrapped + # parser ever fails or succeeds without parsing any input, the `Some` + # object will stop attempting to parse and will return the array of + # previous successes. + # + # `Some` will raise a `ParserFail` exception if the parser never succeeds + # or consumes input. For cases where parsing should allow for 0 successes, + # use `Many`. + class Some(T, V) < Parser(T, Array(V)) + @p : Assert(T, Array(V)) + + # Accepts the parser to use. + def initialize(p : Parser(T, V)) + @p = Many.new(p).assert { |arr| !arr.empty? } + end + + # Continuously parses with the wrapped parser, returns all successes. + # Fails if there are no successes. + def parse(tokens : Tokens(T)) : Result(T, Array(V)) + @p.parse(tokens) + rescue ex : ParserFail + raise ParserFail.new("Some: #{ex.message}") + end + end +end + -- cgit v1.2.1