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authorMatthew Hall <hallmatthew314@gmail.com>2023-03-19 23:02:29 +1300
committerMatthew Hall <hallmatthew314@gmail.com>2023-03-19 23:02:29 +1300
commit9734fa2d530b9496b70a388a117ea57fe5730772 (patch)
tree78a42db1e64e5148edfa96cb2a451a17ef362485 /src/__OLD_parcom/assert.cr
parent2ef8841e9c7a48eea0f66cfe09d8fe996f43c2b2 (diff)
Remove old files
Diffstat (limited to 'src/__OLD_parcom/assert.cr')
-rw-r--r--src/__OLD_parcom/assert.cr45
1 files changed, 0 insertions, 45 deletions
diff --git a/src/__OLD_parcom/assert.cr b/src/__OLD_parcom/assert.cr
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--- a/src/__OLD_parcom/assert.cr
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@@ -1,45 +0,0 @@
-require "./parser.cr"
-
-module Parcom
- # `Assert` is a `Parser` that runs another `Parser` and then
- # performs a test on its result. The parser will then either fail if
- # the result does not pass the test, or forward it on if it does.
- #
- # Example:
- # ```
- # letter = Assert.new(AnyToken(Char).new) { |x| x.letter? }
- # non_letter = Assert.new(AnyToken(Char).new) { |x| !x.letter? }
- # input = Tokens.from_string("hi")
- # letter.parse(input) # this succeeds
- # non_letter.parse(input) # this fails
- # ```
- #
- # `Assert` instance can also be created by calling
- # `Parser#assert` on any parser:
- # ```
- # # This parser is identical to the above example.
- # letter = AnyToken.new(Char).assert { |x| x.letter? }
- # ```
- class Assert(T, V) < Parser(T, V)
- # Accepts the parser to run and a `Bool`-retuning block
- # containing the test to perform on the other parser's result.
- def initialize(@p : Parser(T, V), &block : V -> Bool)
- @f = block
- end
-
- # Runs the parser it was initialized with, and returns that parser's
- # result if it passes the provided test. Raises `ParserFail` otherwise.
- def parse(tokens : Tokens(T)) : Result(T, V)
- result = @p.parse(tokens)
- rescue ex : ParserFail
- raise ParserFail.new("Assert (pre-assertion): #{ex.message}")
- else
- unless @f.call(result.value)
- raise ParserFail.new("Assert: predicate failed for <#{result.value}>")
- end
-
- return result
- end
- end
-end
-