nyacc version 0.71.0 is released as beta
nyacc is a LALR parser generator written from the ground up in guile
Features/Updates:
* clean scheme-flavored syntax for grammar specification
* prototype parsers for C99,(partial) javascript, matlab that output parse
trees in a SXML format
* update: C99 preprocessor updated to expand defines in C code
* update: cleaned up file structure
* update: started working on test-suite
* update: added grammar for C++
* update: build parsers via bison
+ to use in example below replace `make-lalr-machine' with
`make-lalr-machine/bison’,
after adding (use-module (nyacc bison)
+ the bison module will
- export a bison gram.y file,
- run "bison -x gram.y” to produce a gram.xml file
- translate gram.xml file into the nyacc “machine” data structure
To run a simple demo:
$ tar xzf nyacc-0.71.tar.gz
$ cd examples/nyacc/lang/calc
$ ./calc
2 + 2 => 4
Tcalc.scm:
(use-modules (nyacc lalr))
(use-modules (nyacc lex))
(use-modules (nyacc parse))
(define simple-spec
(lalr-spec
(prec< (left "+" "-") (left "*" "/"))
(start expr)
(grammar
(expr
(expr "+" expr ($$ (+ $1 $3)))
(expr "-" expr ($$ (- $1 $3)))
(expr "*" expr ($$ (* $1 $3)))
(expr "/" expr ($$ (/ $1 $3)))
($fixed ($$ (string->number $1)))
($float ($$ (string->number $1)))
("(" expr ")" ($$ $2))))))
(define simple-mach (make-lalr-machine simple-spec))
(define match-table (assq-ref simple-mach 'mtab))
(define gen-lexer (make-lexer-generator match-table))
(define parse (make-lalr-parser simple-mach))
(define demo-string "2 + 2")
(simple-format #t "~A => ~A\n"
demo-string
(with-input-from-string demo-string
(lambda () (parse (gen-lexer)))))
download tarball from:
http://download.savannah.gnu.org/releases/nyacc/
<http://download.savannah.gnu.org/releases/nyacc/>
or git clone from
git://git.savannah.nongnu.org/nyacc.git
<git://git.savannah.nongnu.org/nyacc.git>
