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-rw-r--r--src/__OLD_parcom/phrase.cr33
1 files changed, 33 insertions, 0 deletions
diff --git a/src/__OLD_parcom/phrase.cr b/src/__OLD_parcom/phrase.cr
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+++ b/src/__OLD_parcom/phrase.cr
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+require "./parser.cr"
+require "./eof.cr"
+require "./map.cr"
+
+module Parcom
+ # `Phrase` is a `Parser` that tries to parse with another parser,
+ # but will fail if any of the input has not been consumed.
+ #
+ # Example:
+ # ```
+ # letter_a = Token.new('a')
+ # tokens = Tokens.from_string("aaa")
+ # one_a = Phrase(Char, Char).new(letter_a)
+ # result = one_a.parse(tokens) # This fails
+ # ```
+ class Phrase(T, V) < Parser(T, V)
+ @p : Map(T, {V, Nil}, V)
+
+ # Accepts the parser to parse with.
+ def initialize(p : Parser(T, V))
+ @p = (p + EOF(T).new).map &.first
+ end
+
+ # Tries to parse with the given parser, fails if there
+ # is any un-parsed input remaining.
+ def parse(tokens : Tokens(T)) : Result(T, V)
+ @p.parse(tokens)
+ rescue ex : ParserFail
+ raise ParserFail.new("Phrase: #{ex.message}")
+ end
+ end
+end
+