diff options
| -rw-r--r-- | src/parcom.cr | 12 | ||||
| -rw-r--r-- | src/parcom/peek.cr | 23 |
2 files changed, 23 insertions, 12 deletions
diff --git a/src/parcom.cr b/src/parcom.cr index 4612887..39329f7 100644 --- a/src/parcom.cr +++ b/src/parcom.cr @@ -81,18 +81,6 @@ module Parcom end end - class Peek(T, V) < Parser(T, V) - def initialize(@p : Parser(T, V)) - end - - def parse(tokens : Tokens(T)) : Result(T, V) - result = @p.parse(tokens) - Result.new(tokens, result.value) - rescue ex : ParserFail - raise ParserFail.new("Peek: #{ex.message}") - end - end - class Assert(T, V) < Parser(T, V) def initialize(@p : Parser(T, V), &block : V -> Bool) @f = block diff --git a/src/parcom/peek.cr b/src/parcom/peek.cr new file mode 100644 index 0000000..2b6f657 --- /dev/null +++ b/src/parcom/peek.cr @@ -0,0 +1,23 @@ +require "./parser.cr" + +module Parcom + # `Peek` is a `Parser` that runs another `Parser` while + # leaving the input stream unmodified. + class Peek(T, V) < Parser(T, V) + # Accepts the parser to run. + def initialize(@p : Parser(T, V)) + end + + # Runs the parser it was initialized with, and returns + # that parser's result along with the original input. + # + # Re-raises a `ParserFail` exception if the other parser fails. + def parse(tokens : Tokens(T)) : Result(T, V) + result = @p.parse(tokens) + Result.new(tokens, result.value) + rescue ex : ParserFail + raise ParserFail.new("Peek: #{ex.message}") + end + end +end + |