> On Oct 17, 2015, at 12:02 PM, Matt Wette <matthew.we...@verizon.net> wrote: > I am playing with the compiler tower and have been digging through the > (system base language) module to try to get my hands around writing to the > compiler tower. .
Here is a simple calculator example that I have working with my own intermediate (SXML based) language. scheme@(guile-user)> ,L calc Happy hacking with calc! To switch back, type `,L scheme'. calc@(guile-user)> a = (2.5 + 4.5)/(9.3 - 1) calc@(guile-user)> ,L scheme Happy hacking with Scheme! To switch back, type `,L calc'. scheme@(guile-user)> a $1 = 0.8433734939759036 The implementation consists of the files spec.scm, parser.scm and compiler.scm which are listed below. All files are: ;;; Copyright (C) 2015 Matthew R. Wette ;;; ;;; This program is free software: you can redistribute it and/or modify ;;; it under the terms of the GNU General Public License as published by ;;; the Free Software Foundation, either version 3 of the License, or ;;; (at your option) any later version. and to appear at https://savannah.nongnu.org/projects/nyacc <https://savannah.nongnu.org/projects/nyacc>. spec.scm: (define-module (language calc spec) #:export (calc) #:use-module (system base language) #:use-module (nyacc lang calc parser) #:use-module (nyacc lang calc compiler)) (define (calc-reader port env) (let ((iport (current-input-port))) (dynamic-wind (lambda () (set-current-input-port port)) (lambda () (calc-parse #:debug #f)) (lambda () (set-current-input-port iport))))) (define-language calc #:title "calc" #:reader calc-reader #:compilers `((tree-il . ,calc-sxml->tree-il)) #:printer write) parser.scm: (define-module (nyacc lang calc parser) #:export (calc-parse calc-spec calc-mach) #:use-module (nyacc lalr) #:use-module (nyacc lex) #:use-module (nyacc parse) ) (define calc-spec (lalr-spec (prec< (left "+" "-") (left "*" "/")) (start stmt-list-proxy) (grammar (stmt-list-proxy (stmt-list "\n" ($$ (cons 'stmt-list (reverse $1))))) (stmt-list (stmt ($$ (list $1))) (stmt-list ";" stmt ($$ (cons $3 $1)))) (stmt (ident "=" expr ($$ `(assn-stmt ,$1 ,$3))) (expr ($$ `(expr-stmt ,$1))) ( ($$ '(empty-stmt)))) (expr (expr "+" expr ($$ `(add ,$1 ,$3))) (expr "-" expr ($$ `(sub ,$1 ,$3))) (expr "*" expr ($$ `(mul ,$1 ,$3))) (expr "/" expr ($$ `(div ,$1 ,$3))) ('$fixed ($$ `(fixed ,$1))) ('$float ($$ `(float ,$1))) ("(" expr ")" ($$ $2))) (ident ('$ident ($$ `(ident ,$1)))) ))) (define calc-mach (compact-machine (hashify-machine (make-lalr-machine calc-spec)))) (define calc-parse (let ((gen-lexer (make-lexer-generator (assq-ref calc-mach 'mtab) #:space-chars " \t")) (parser (make-lalr-ia-parser calc-mach))) (lambda* (#:key (debug #f)) (parser (gen-lexer) #:debug debug)))) compiler.scm: (define-module (nyacc lang calc compiler) #:export (calc-sxml->tree-il) #:use-module (sxml match) #:use-module (sxml fold) ;;#:use-module (system base language) #:use-module (language tree-il)) (define (fup tree) (sxml-match tree ((fixed ,fx) `(const ,(string->number fx))) ((float ,fl) `(const ,(string->number fl))) ((ident ,id) `(toplevel ,(string->symbol id))) ((add ,lt ,rt) `(apply (toplevel +) ,lt ,rt)) ((sub ,lt ,rt) `(apply (toplevel -) ,lt ,rt)) ((mul ,lt ,rt) `(apply (toplevel *) ,lt ,rt)) ((div ,lt ,rt) `(apply (toplevel /) ,lt ,rt)) ((assn-stmt (toplevel ,lhs) ,rhs) `(define ,lhs ,rhs)) ((empty-stmt) '(begin)) ((stmt-list ,items ...) `(begin ,items ...)) (,otherwise tree))) (define (calc-sxml->tree-il exp env opts) (let* ((tree (foldt fup identity exp)) (code (parse-tree-il tree))) (values code env env)))
