Thanks Mark.
I did make progress on this. I also discovered that I need to use the optional
specification of ellipses (i..e, :::) in the top-level macro to avoid clash
with ellipses in the letrec-syntax part.
For information, the project is an LALR parser generator which has a Scheme
flavor for specifying grammars. There is no need to declare tokens: the macro
uses a fender to differentiate non-terminals (e.g., expr) from terminals (e.g.,
'float, #\+). The code turns out to be pretty clean and compact, I believe.
I plan to use the local bindings to provide macros for common patterns (e.g.,
($opt 'const) int => opt-1 'int , (opt-1 () ('const)).
Matt
(define spec0
(lalr2-spec
(start expr)
(grammar
(expr
(expr #\+ term ($action (+ $1 $3)))
(expr #\- term ($action (- $1 $3)))
(term))
(term
(term #\* factor ($action (* $1 $3)))
(term #\/ factor ($action (/ $1 $3)))
(factor))
(factor ('integer) ('float))
)))
