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Diffstat (limited to 'src/__OLD_parcom/some.cr')
| -rw-r--r-- | src/__OLD_parcom/some.cr | 33 |
1 files changed, 33 insertions, 0 deletions
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 + |
