Hi,
I'm using the Happy parser, and I've threaded a Success/Failure
monad-like thing through it so that if the parse succeeds, Success AST
(AST is the datatype I want to turn my tokens into) is returned and if
it fails, Fail String is returned (in a similar manner to how such
threading is described in the Happy Documentation). That is, data SorF
a = Succeed a | Fail String. Now, if the input is valid, I get the
correct result (namely Success AST). If invalid input is given (ie the
wrong token is encountered), happyError is triggered correctly, and and
a Fail String is returned. However, if incomplete info is given (let's
say a rule is expecting two tokens, and only one is read before the end
of input), the parser generated by happy throws error("Reading EOF"). I
have defined happyError on both the empty list of tokens, and the
non-empty list as returning a Fail String. I'm stumped as to why I get
this error.
Any advice?
Best,
Mike.
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