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* happyError should take the current token as an argument in %lexer mode;
it's silly not to, because it means the monad has to keep track of the
previous token in order to report it in the error message.
* allow polymorphic type signatures for productions.
* allow omitted semnatic values, defaulting to $1?
* unlit properly
* maintain indentation in code between { } so that layout works.
-OLD-------------------------------------------------------------------------
1. Add in a simple lexical analyser
2. Add in choice for lexical analyis
%lexerstyle original -- the default
%lexerstyle auto
%lexerstyle monadic
---[1] :: [Token] -> a ---------------------------------------------------------
As things are now :-(
---[2] :: String -> a ----------------------------------------------------------
Using the special lexer, as defined using
%macro letter ( [A-Z][a-z] )
%autotoken
id ( {letter}({digit}|{letter}) )
---[3] :: ParseM Token -> ParseM a ---------------------------------------------
This presumes the exsitance of the defintions:
type ParseM a b c = a -> ParseR a b
data ParseR a b c = ParseSucc a b | ParseFail c
thenPM :: a -> ParseM a b c
returnPM :: ParseM a b c -> (a -> ParseM d b c) -> ParseM d b c ->
and is intended for *serious* parsers, like our Haskell parser.
You need to give a %eof
-----------------------------------------------------------------------------
******************************************************************************
ToAdd:
--magic-name Sad
allows other names to be used as the *Magic* name, currently
only Happy.
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