280 lines
11 KiB
Scheme
280 lines
11 KiB
Scheme
;;; nyacc/lang/c99/cppbody.scm
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;;;
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;;; Copyright (C) 2016-2017 Matthew R. Wette
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;;;
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;;; This program is free software: you can redistribute it and/or modify
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;;; it under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation, either version 3 of the License, or
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;;; (at your option) any later version.
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;;;
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;;; This program is distributed in the hope that it will be useful,
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;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
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(define (cpp-err fmt . args)
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(apply throw 'cpp-error fmt args))
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;;.@deffn skip-il-ws ch
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;; Skip in-line whitespace
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(define skip-il-ws
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(let ((il-ws (list->char-set '(#\space #\tab))))
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(lambda (ch)
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(cond
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((eof-object? ch) ch)
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((char-set-contains? il-ws ch) (skip-il-ws (read-char)))
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(else ch)))))
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;; Since we want to be able to get CPP statements with comment in tact
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;; (e.g., for passing to @code{pretty-print-c99}) we need to remove
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;; comments when parsing CPP expressions. We convert a comm-reader
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;; into a comm-skipper here. And from that generate a lexer generator.
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(define cpp-comm-skipper
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(let ((reader (make-comm-reader '(("/*" . "*/")))))
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(lambda (ch)
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(reader ch #f))))
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;; generate a lexical analyzer per string
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(define gen-cpp-lexer
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(make-lexer-generator mtab #:comm-skipper cpp-comm-skipper))
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;; @deffn parse-cpp-expr text => tree
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;; Given a string returns a cpp parse tree. This is called by
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;; @code{eval-cpp-expr}. The text will have had all CPP defined symbols
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;; expanded already so no identifiers should appear in the text.
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;; A @code{cpp-error} will be thrown if a parse error occurs.
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(define (parse-cpp-expr text)
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(with-throw-handler
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'nyacc-error
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(lambda ()
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(with-input-from-string text
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(lambda () (raw-parser (gen-cpp-lexer)))))
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(lambda (key fmt . args)
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(apply throw 'cpp-error fmt args))))
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;; @deffn eval-cpp-expr tree dict => datum
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;; Evaluate a tree produced from @code{parse-cpp-expr}.
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;; The tree passed to this routine is
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(define (eval-cpp-expr tree dict)
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(letrec
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((tx (lambda (tr ix) (list-ref tr ix)))
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(tx1 (lambda (tr) (tx tr 1)))
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(ev (lambda (ex ix) (eval-expr (list-ref ex ix))))
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(ev1 (lambda (ex) (ev ex 1))) ; eval expr in arg 1
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(ev2 (lambda (ex) (ev ex 2))) ; eval expr in arg 2
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(ev3 (lambda (ex) (ev ex 3))) ; eval expr in arg 3
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(eval-expr
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(lambda (tree)
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(case (car tree)
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((fixed) (string->number (tx1 tree)))
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((char) (char->integer (tx1 tree)))
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((defined) (if (assoc-ref dict (tx1 tree)) 1 0))
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((pre-inc post-inc) (1+ (ev1 tree)))
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((pre-dec post-dec) (1- (ev1 tree)))
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((pos) (ev1 tree))
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((neg) (- (ev1 tree)))
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((bw-not) (bitwise-not (ev1 tree)))
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((not) (if (zero? (ev1 tree)) 1 0))
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((mul) (* (ev1 tree) (ev2 tree)))
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((div) (/ (ev1 tree) (ev2 tree)))
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((mod) (modulo (ev1 tree) (ev2 tree)))
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((add) (+ (ev1 tree) (ev2 tree)))
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((sub) (- (ev1 tree) (ev2 tree)))
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((lshift) (bitwise-arithmetic-shift-left (ev1 tree) (ev2 tree)))
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((rshift) (bitwise-arithmetic-shift-right (ev1 tree) (ev2 tree)))
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((lt) (if (< (ev1 tree) (ev2 tree)) 1 0))
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((le) (if (<= (ev1 tree) (ev2 tree)) 1 0))
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((gt) (if (> (ev1 tree) (ev2 tree)) 1 0))
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((ge) (if (>= (ev1 tree) (ev2 tree)) 1 0))
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((equal) (if (= (ev1 tree) (ev2 tree)) 1 0))
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((noteq) (if (= (ev1 tree) (ev2 tree)) 0 1))
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((bw-or) (bitwise-ior (ev1 tree) (ev2 tree)))
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((bw-xor) (bitwise-xor (ev1 tree) (ev2 tree)))
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((bw-and) (bitwise-and (ev1 tree) (ev2 tree)))
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((or) (if (and (zero? (ev1 tree)) (zero? (ev2 tree))) 0 1))
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((and) (if (or (zero? (ev1 tree)) (zero? (ev2 tree))) 0 1))
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((cond-expr) (if (zero? (ev1 tree)) (ev3 tree) (ev2 tree)))
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((ident) (cpp-err "undefined identifier: ~S" (cadr tree)))
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(else (error "incomplete implementation"))))))
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(eval-expr tree)))
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;; Note: scan-cpp-input scans replacement text. When identifiers are found
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;; they are tested for expansion as follows:
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;; @enumerate
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;; @item If already expanded, then ignore.
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;; @item If followed by @code{(}, then use @code{collect-args} to get the
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;; arguments and ...
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;; @item Otherwise insert the replacement text and continue scanning (at
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;; first character of new replacement text.
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;; @end enumerate
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;; @deffn scan-cpp-input argd used dict end-tok => string
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;; Process replacement text from the input port and generate a (reversed)
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;; token-list. If end-tok, stop at, and push back, @code{,} or @code{)}.
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;; If end-tok is @code{,} then read until @code{,} or @code{(}.
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;; The argument @var{argd} is a dictionary (argument name, argument
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;; value) pairs which will be expanded as needed. This routine is called
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;; by collect-args, expand-cpp-repl and cpp-expand-text.
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(define (scan-cpp-input argd dict used end-tok)
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;; Works like this: scan tokens (comments, parens, strings, char's, etc).
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;; Tokens (i.e., strings) are collected in a (reverse ordered) list (stl)
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;; and merged together on return. Lone characters are collected in the
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;; list @code{chl}. Once a token border is seen the character list is
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;; converted to a string and added to the string list first, followed by
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;; the new token.
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;; Turn reverse chl into a string and insert it into the string list stl.
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(define (add-chl chl stl)
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(if (null? chl) stl (cons (list->string (reverse chl)) stl)))
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;; used when we see `#foo'; converts foo to "foo"
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(define (stringify str)
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(string-append "\"" str "\""))
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(define conjoin string-append)
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;; We just scanned "defined", now need to scan the arg to inhibit expansion.
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;; For example, we have scanned "defined"; we now scan "(FOO)" or "FOO", and
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;; return "defined(FOO)". We use ec (end-char) as terminal char:
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;; #\) if starts with #( or #\nul if other.
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(define (scan-defined-arg)
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(let* ((ch (skip-il-ws (read-char)))
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(ec (if (char=? ch #\() #\) #\null)))
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(let iter ((chl '(#\()) (ec ec) (ch (if (char=? ec #\)) (read-char) ch)))
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(cond
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((eof-object? ch)
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(if (char=? ec #\null)
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(string-append "defined" (list->string (reverse (cons #\) chl))))
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(cpp-err "illegal argument to `defined'")))
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((char-set-contains? c:ir ch)
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(iter (cons ch chl) ec (read-char)))
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((char=? ec #\))
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(if (char=? #\) (skip-il-ws ch))
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(string-append "defined" (list->string (reverse (cons #\) chl))))
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(cpp-err "garbage in argument to `defined'")))
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((char=? ec #\null) ;; past identifier
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(string-append "defined" (list->string (reverse (cons #\) chl)))))
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(else
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(cpp-err "illegal argument to `defined'"))))))
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(let iter ((stl '()) ; string list (i.e., tokens)
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(chl '()) ; char-list (current list of input chars)
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(nxt #f) ; next string
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(lvl 0) ; level
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(ch (read-char))) ; next character
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(cond
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;; have item to add, but first add in char's
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(nxt (iter (cons nxt (add-chl chl stl)) '() #f lvl ch))
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;; If end of string or see end-ch at level 0, then return.
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((eof-object? ch) ;; CHECK (ab++)
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(apply string-append (reverse (add-chl chl stl))))
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((and (eqv? end-tok ch) (zero? lvl))
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(unread-char ch) (apply string-append (reverse (add-chl chl stl))))
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((and end-tok (char=? #\) ch) (zero? lvl))
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(unread-char ch) (apply string-append (reverse (add-chl chl stl))))
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((read-c-comm ch #f) =>
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(lambda (cp) (iter stl chl (string-append "/*" (cdr cp) "*/")
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lvl (read-char))))
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;; not sure about this:
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((char-set-contains? c:ws ch) (iter stl chl nxt lvl (read-char)))
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((char=? #\( ch) (iter stl (cons ch chl) nxt (1+ lvl) (read-char)))
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((char=? #\) ch) (iter stl (cons ch chl) nxt (1- lvl) (read-char)))
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((char=? #\# ch)
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(let ((ch (read-char)))
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(if (eqv? ch #\#)
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(iter stl chl "##" lvl (read-char))
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(iter stl chl "#" lvl ch))))
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((read-c-string ch) =>
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(lambda (st) (iter stl chl st lvl (read-char))))
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((read-c-ident ch) =>
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(lambda (iden)
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(if (equal? iden "defined")
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;; "defined" is a special case
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(let ((arg (scan-defined-arg)))
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(iter stl chl arg lvl (read-char)))
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;; otherwise ...
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(let* ((aval (assoc-ref argd iden)) ; lookup argument
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(rval (assoc-ref dict iden))) ; lookup macro def
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(cond
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((and (pair? stl) (string=? "#" (car stl)))
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(iter (cdr stl) chl (stringify aval) lvl (read-char)))
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((and (pair? stl) (string=? "##" (car stl)))
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(iter (cddr stl) chl (conjoin (cadr stl) aval) lvl (read-char)))
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((member iden used) ; name used
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(iter stl chl iden lvl (read-char)))
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(aval ; arg ref
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(iter stl chl aval lvl (read-char)))
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((string? rval) ; cpp repl
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(iter stl chl rval lvl (read-char)))
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((pair? rval) ; cpp macro
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(let* ((argl (car rval)) (text (cdr rval))
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(argd (collect-args argl argd dict used))
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(newl (expand-cpp-repl text argd dict (cons iden used))))
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(iter stl chl newl lvl (read-char))))
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(else ; normal identifier
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(iter stl chl iden lvl (read-char))))))))
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(else
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(iter stl (cons ch chl) #f lvl (read-char))))))
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;; @deffn collect-args argl argd dict used => argd
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;; to be documented
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;; I think argd is a passthrough for scan-cpp-input
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;; argl: list of formal arguments in #define
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;; argd: used? (maybe just a pass-through for scan-cpp-input
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;; dict: dict of macro defs
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;; used: list of already expanded macros
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;; TODO clean this up
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;; should be looking at #\( and eat up to matching #\)
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(define (collect-args argl argd dict used)
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(let iter ((argl argl) (argv '()) (ch (skip-il-ws (read-char))))
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;; ch should always be #\(, #\, or #\)
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(cond
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((eqv? ch #\)) (reverse argv))
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((null? argl) (cpp-err "arg count"))
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((and (null? (cdr argl)) (string=? (car argl) "..."))
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(let ((val (scan-cpp-input argd dict used #\))))
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(iter (cdr argl) (acons "__VA_ARGS__" val argv) (read-char))))
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((or (eqv? ch #\() (eqv? ch #\,))
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(let ((val (scan-cpp-input argd dict used #\,)))
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(iter (cdr argl) (acons (car argl) val argv) (read-char))))
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(else (error "coding error, ch=" ch)))))
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;; @deffn expand-cpp-repl
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;; to be documented
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(define (expand-cpp-repl repl argd dict used)
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(with-input-from-string repl
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(lambda () (scan-cpp-input argd dict used #f))))
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;; @deffn cpp-expand-text text dict => string
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(define (cpp-expand-text text dict)
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(with-input-from-string text
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(lambda () (scan-cpp-input '() dict '() #f))))
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;; @deffn expand-cpp-mref ident dict => repl|#f
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;; Given an identifier seen in C99 input, this checks for associated
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;; definition in @var{dict} (generated from CPP defines). If found,
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;; the expansion is returned as a string. If @var{ident} refers
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;; to a macro with arguments, then the arguments will be read from the
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;; current input.
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(define (expand-cpp-mref ident dict . rest)
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(let ((used (if (pair? rest) (car rest) '()))
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(rval (assoc-ref dict ident)))
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(cond
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((not rval) #f)
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((member ident used) ident)
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((string? rval)
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(let ((expd (expand-cpp-repl rval '() dict (cons ident used))))
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expd))
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((pair? rval)
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(let* ((argl (car rval)) (repl (cdr rval))
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(argd (collect-args argl '() dict '()))
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(expd (expand-cpp-repl repl argd dict (cons ident used))))
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expd)))))
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;;; --- last line ---
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