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|
;; Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
;; All rights reserved.
;; Copyright (C) 2007-2011, Gabriel Dos Reis.
;; All rights reserved.
;;
;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions are
;; met:
;;
;; - Redistributions of source code must retain the above copyright
;; notice, this list of conditions and the following disclaimer.
;;
;; - Redistributions in binary form must reproduce the above copyright
;; notice, this list of conditions and the following disclaimer in
;; the documentation and/or other materials provided with the
;; distribution.
;;
;; - Neither the name of The Numerical ALgorithms Group Ltd. nor the
;; names of its contributors may be used to endorse or promote products
;; derived from this software without specific prior written permission.
;;
;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
;; IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
;; TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
;; PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
;; OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
;; EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
;; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;; PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
; NAME: META/LISP Parser Generator and Lexical Analysis Utilities (Parsing)
;
; PURPOSE: This package provides routines to support the Metalanguage
; translator writing system. Metalanguage is described
; in META/LISP, R.D. Jenks, Tech Report, IBM T.J. Watson Research Center,
; 1969. Familiarity with this document is assumed.
;
; The parser generator itself is described in either the file
; MetaBoot.lisp (hand-coded version) or the file MetaMeta.lisp (machine
; generated from self-descriptive Meta code), both of which load themselves
; into package Parsing.
; CONTENTS:
;
; 0. Current I/O Stream definition
;
; 1. Data structure declarations (defstructs) for parsing objects
;
; A. Line Buffer
; B. Stack
; C. Token
; D. Reduction
;
; 2. Recursive descent parsing support routines
; A. Stacking and retrieving reductions of rules.
; B. Applying metagrammatical elements of a production (e.g., Star).
;
; 3. Routines for handling lexical scanning
;
; A. Manipulating the token stack and reading tokens
; B. Error handling
; C. Constructing parsing procedures
; D. Managing rule sets
;
; 4. Tracing routines
;
; 5. Routines for inspecting and resetting total I/O system state
;
; METALEX.LISP: Meta file handling, auxiliary parsing actions and tokenizing
;
; BOOTLEX.LISP: Boot file handling, auxiliary parsing actions and tokenizing
; NEWMETA.LISP: Boot parsing
(import-module "metalex")
(in-package "BOOT")
(defun IOStreams-Show ()
(format t "~&Input is coming from ~A, and output is going to ~A.~%"
(or (streamp in-stream) "the keyboard")
(or (streamp out-stream) "the screen"))
(format t "~:[~;The current input stream is logically closed.~%~]~%" File-Closed))
(defmacro IOStreams-Set (input output) `(setq in-stream ,input out-stream ,output))
(defmacro IOStreams-Clear (&optional (in t) (out t))
`(progn (and (streamp in-stream) (close in-stream))
(and (streamp out-stream) (close out-stream))
(setq File-Closed nil)
(IOStreams-Set ,in ,out)))
; 2B. Routines for applying certain metagrammatical elements
; of a production (e.g., Star).
; Must means that if it is not present in the token stream, it is a syntax error.
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Star, Bang, Must, Optional, Action
(defmacro Star (lab prod)
"Succeeds if there are one or more of PROD, stacking as one unit
the sub-reductions of PROD and labelling them with LAB.
E.G., (Star IDs (parse-id)) with A B C will stack (3 IDs (A B C)),
where (parse-id) would stack (1 ID (A)) when applied once."
`(prog ((oldstacksize (|stackSize| |$reduceStack|)))
(if (not ,prod) ;(progn (format t "~&Star failed for ~A.~%" ',lab) (return nil)))
(return nil))
loop (if (not ,prod)
(let* ((newstacksize (|stackSize| |$reduceStack|))
(number-of-new-reductions (- newstacksize oldstacksize)))
; (format t "~&Starring ~A with ~D new reductions.~%"
; ',lab number-of-new-reductions)
(if (> number-of-new-reductions 0)
(return (do ((i 0 (1+ i)) (accum nil))
((= i number-of-new-reductions)
(|pushReduction| ',lab accum)
; (format t "~&Star accumulated ~D reductions.~%"
; (length accum))
(return t))
(push (|popStack1|) accum)))
(return t)))
(go loop))))
(defmacro Bang (lab prod)
"If the execution of prod does not result in an increase in the size of
the stack, then stack a NIL. Return the value of prod."
`(progn (setf (|stackUpdated?| |$reduceStack|) nil)
(let* ((prodvalue ,prod)
(updated (|stackUpdated?| |$reduceStack|)))
(if updated
(progn ; (format t "~&Banged ~A and I think the stack is updated!~%" ',lab)
prodvalue)
(progn (|pushReduction| ',lab nil)
prodvalue)))))
(defmacro must (dothis &optional (this-is nil) (in-rule nil))
`(or ,dothis (spad_syntax_error ,this-is ,in-rule)))
; Optional means that if it is present in the token stream, that is a good thing,
; otherwise don't worry (like [ foo ] in BNF notation).
(defun Optional (dothis) (or dothis t))
; Action is something we do as a consequence of successful parsing; it is
; inserted at the end of the conjunction of requirements for a successful
; parse, and so should return T.
(defun action (dothis) (or dothis t))
; 3A. Manipulating the token stack and reading tokens
; This section is broken up into 3 levels:
;
; (0) String grabbing: Match String, Match Advance String
; (1) Token handling: Current Token, Next Token, Advance Token
; (2) Character handling: Current Char, Next Char, Advance Char
; (3) Line handling: Next Line, Print Next Line
; (X) Random Stuff
; 3A (0). String grabbing
; String grabbing is the art of matching initial segments of the current
; line, and removing them from the line before the get tokenized if they
; match (or removing the corresponding current tokens).
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Match-String, Match-Advance-String
(defun Match-String (x)
"Returns length of X if X matches initial segment of inputstream."
(unget-tokens) ; So we don't get out of synch with token stream
(skip-blanks)
(if (and (not (Line-Past-End-P Current-Line)) (Current-Char) )
(initial-substring-p x
(subseq (Line-Buffer Current-Line) (Line-Current-Index Current-Line)))))
(defun Match-Advance-String (x)
"Same as MATCH-STRING except if successful, advance inputstream past X."
(let ((y (if (>= (length (string x))
(length (string (quote-if-string (|currentToken|)))))
(Match-String x)
nil))) ; must match at least the current token
(if y (progn (incf (Line-Current-Index Current-Line) y)
(if (not (Line-Past-End-P Current-Line))
(setf (Line-Current-Char Current-Line)
(elt (Line-Buffer Current-Line)
(Line-Current-Index Current-Line)))
(setf (Line-Current-Char Current-Line) #\Space))
(setq |$priorToken|
(|makeToken| (intern (string x)) 'identifier |$nonblank|))
t))))
(defun match-advance-keyword (str)
(and (|matchToken| (|currentToken|) 'keyword (intern str))
(action (|advanceToken|))))
(defun match-advance-special (str)
(and (|matchToken| (|currentToken|) 'special-char (character str))
(action (|advanceToken|))))
(defun match-special (str)
(|matchToken| (|currentToken|) 'special-char (character str)))
(defun match-keyword-next (str)
(|matchToken| (|nextToken|) 'keyword (intern str)))
(defun initial-substring-p (part whole)
"Returns length of part if part matches initial segment of whole."
(let ((x (string<= part whole)))
(and x (= x (length part)) x)))
; 3B. Error handling
(defparameter errcol nil)
(defparameter line nil)
(defun conversation (x y)
(prog (u)
a (|reduceStackClear|)
(setq u (namederrset 'spad_reader (conversation1 x y) ))
(cond (*eof* (return nil))
((atom u) (go a))
((return (car u))))))
(defparameter ulcasefg nil "")
(defun conversation1 (firstfun procfun)
(prog nil
top(cond ((not (Current-Char)) (return nil))
((and (|currentToken|) (|nextToken|)) (go top))
((compfin) (return 't))
((and (funcall firstfun)
(or (funcall procfun (|popStack1|))))
(go top))
((compfin) (return 't)) )
(spad_syntax_error)
(go top)))
(defun termchr () "Is CHR a terminating character?"
(position (current-char) " *,;<>()[]/\\"))
(defun compfin () (or (match-string ")fin") (match-string ".FIN")))
; 3 C. Constructing parsing procedures
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Make-Parse-Function, GetGenSym
(MAKEPROP 'PROGN 'NARY T) ; Setting for Make-Parse-Function
(defun make-parse-function (l op)
(if (flagp op 'nary) (setq l (make-parse-func-flatten-1 l op nil)))
(make-parse-function1 l op))
(defun make-parse-func-flatten (x op)
(cond ((atom x) x)
((eq (car x) op) (cons op (make-parse-func-flatten-1 (cdr x) op nil)))
(t (cons (make-parse-func-flatten (car x) op) (make-parse-func-flatten (cdr x) op)))))
(defun make-parse-func-flatten-1 (l op r)
(let (x)
(if (null l)
r
(make-parse-func-flatten-1
(cdr l) op
(append r (if (eqcar (setq x (make-parse-func-flatten (car l) op)) op)
(cdr x)
(list x)))))))
(defun make-parse-function1 (l op)
(let (x)
(case op
(plus (cond ((eq 0 (setq x (length (setq l (s- l '(0 (zero))))))) 0)
((eq 1 x) (car l))
(t `(+ . ,l))))
(times (cond ((s* l '(0 (zero))) 0)
((eq 0 (setq x (length (setq l (s- l '(1 (one))))))) 1)
((eq 1 x) (car l))
(t `(times . ,l)) ))
(quotient (cond ((> (length l) 2) (fail))
((eq 0 (car l)) 0)
((eq (cadr l) 1) (car l))
(t `(quotient . ,l)) ))
(minus (cond ((cdr l) (fail))
((numberp (setq x (car l))) (minus x))
((eqcar x 'minus) (cadr x))
(t `(minus . ,l)) ))
(- (cond ((> (length l) 2) (fail))
((equal (car l) (cadr l)) '(zero))
((member (car l) '(0 (zero))) (make-parse-function (cdr l) 'minus))
((member (cadr l) '(0 (zero))) (car l))
((eqcar (cadr l) 'minus)
(make-parse-function (list (car l) (cadadr l)) 'plus))
(t `(- . ,l)) ))
(expt (cond ((> (length l) 2) (fail))
((eq 0 (cadr l)) 1)
((eq 1 (cadr l)) (car l))
((member (car l) '(0 1 (zero) (one))) (car l))
(t `(expt . ,l)) ))
(or (cond ((member 't l) ''t)
((eq 0 (setq x (length (setq l (delete nil l))))) nil)
((eq 1 x) (car l))
(t `(or . ,l)) ))
(|or| (cond ((member 't l) 't)
((eq 0 (setq x (length (setq l (delete nil l))))) nil)
((eq 1 x) (car l))
(t `(|or| . ,l)) ))
(null (cond ((cdr l) (fail))
((eqcar (car l) 'null) (cadar l))
((eq (car l) 't) nil)
((null (car l)) ''t)
(t `(null . ,l))))
(|and| (cond ((eq 0 (setq x (length (setq l (delete 't (delete 'true l)))))) 't)
((eq 1 x) (car l))
(t `(|and| . ,l)) ))
(and (cond ((eq 0 (setq x (length (setq l (delete 't (delete 'true l)))))) ''t)
((eq 1 x) (car l))
(t `(and . ,l)) ))
(progn (cond ((and (not (atom l)) (null (last l)))
(cond ((cdr l) `(progn . ,l))
(t (car l))))
((null (setq l (delete nil l))) nil)
((cdr l) `(progn . ,l))
(t (car l)) ))
(seq (cond ((eqcar (car l) 'exit) (cadar l))
((cdr l) `(seq . ,l))
(t (car l)) ))
(list (cond ((null l) nil) (t `(list . ,l))))
(cons (cond ((cdr l) `(cons . ,l)) (t (car l)) ))
(t (cons op l) ))))
(defparameter /genvarlst nil "??")
(defun transpgvar (metapgvar) (remove-duplicates metapgvar))
(defparameter /gensymlist nil "List of rule local variables generated by getgensym.")
(defun getgensym (n)
"Used to create unique numerically indexed local variables for the use of rules."
(loop
(let ((m (length /gensymlist)))
(if (< m n)
(setq /gensymlist (|append!| /gensymlist `(,(intern (format nil "G~D" (1+ m))))))
(return (nth (1- n) /gensymlist))))))
; 3 D. Managing rule sets
(defparameter bac nil "")
(defparameter keyfn nil "")
(defparameter /metaoption "")
(defparameter tline nil "")
(defparameter rs nil "")
(defun getrulefunlists (rootfun rs)
(let* ((metapfx (or (get rootfun 'metapfx) ""))
(mainfun (internl metapfx (pname rootfun)))
(mainfunstr (pname mainfun))
(flnam (internl mainfunstr "FUN"))
(pfx-funlist (union (cons mainfun
(if (atom (eval flnam)) nil (eval flnam)))
(mapcar #'(lambda (x) (internl metapfx (pname x)))
(assocleft rs))))
n unpfx-funlist)
(setf (symbol-value flnam) pfx-funlist)
(if (not (lessp (setq n (length metapfx)) 0))
(setq unpfx-funlist
(mapcar #'(lambda (x)
(intern (subseq
(symbol-name (copy-symbol (pname x))) n)))
pfx-funlist)))
(if unpfx-funlist (list pfx-funlist unpfx-funlist))))
; 4. Tracing routines
(defparameter debugmode 'yes "Can be either YES or NO")
(defun reduction-print (y rule)
(format t "~&")
(cond ((eq y t) (|sayBrightly| `(|%b| ,rule |%d| " reduced")))
(y (|sayBrightlyNT| `(|%b| ,rule |%d|))
(format t " reduced ~A~%" y)))
y)
(defmacro tracemeta (&rest l) `(trmeta ',l))
(defparameter /depth 0 "Used in Debug.lisp.")
(defun trmeta (l) (setq /depth 0) (mapc #'trmeta1 l))
(defun trmeta1 (x)
(let (y)
(if (not (fboundp x))
(if (fboundp (setq y (internl $lastprefix (pname x))))
(moan (format nil "********* ~S RENAMED AS ~S" x (setq x y)))
(croak (format nil "********* ~S MUST BE GIVEN PREFIX" x))))
(/embed-1 x
(sublislis
(list (pname x) x (gensym))
'(nam* fun* argl*)
'(lambda (&rest argl*)
(prog (v tok)
(terpri)
(trblanks (* 2 /depth)) (setq /depth (+ 1 /depth))
(princ (stringimage /depth)) (princ "<")
(princ nam*) (trargprint argl*) (princ "/")
(princ "chr= ") (prin1 (Current-Char))
(princ "/tok= ") (prin1 (setq tok (current-symbol)))
(princ "/col= ") (prin1 (line-current-index current-line))
;; (princ "/icol= ") (prin1 initcolumn)
(cond ( (not nonblank) (go a1))) (princ "/nblnk= T")
a1 ;;(cond (ok (go b1))) (princ "/ok= NIL")
b1 ;;(cond ( (not stackx) (go c1))) (princ "/stackx= ")
;;(prin1 stackx)
c1 (cond ( (not (identp tok)) (go d1)))
(princ "/isid= ")
;; (princ (cond (isid "T") (t "NIL")))
d1 (princ "/stack= ") (prin1 (|stackStore| |$reduceStack|))
(setq v (apply fun* argl*)) (setq /depth (- /depth 1))
(terpri)
(trblanks (* 2 /depth)) (princ (stringimage (\1+ /depth)))
(princ ">") (princ nam*)
(princ "/chr= ") (prin1 (Current-Char))
(princ "/tok= ") (prin1 (setq tok (current-symbol)))
(princ "/col= ") (prin1 (line-current-index current-line))
(if (not nonblank) (go a2)) (princ "/nblnk= ")
(princ (if nonblank "T" "NIL"))
a2 ;;(if ok (go b2)) (princ "/ok= ") (prin1 ok)
b2 ;;(if (not stackx) (go c2)) (princ "/stackx1= ") (prin1 stackx)
c2 (if (not (identp tok)) (go d2))
(princ "/isid= ")
;; (princ (if isid "T" "NIL"))
d2 (princ "/stack= ") (prin1 (|stackStore| |$reduceStack|))
(princ "/value= ") (prin1 v)
(return v)))))))
(defun /embed-1 (x y)
(princ (strconc (pname x) " embedded"))
(terpri)
(/embed-q x y))
(defvar /embednames)
(defun /embed-q (x y)
(setq /embednames (cons x /embednames))
(embed x
(cond ((eqcar y 'lambda) y)
((eqcar y 'before)
`(lambda ,(cadr y)
(prog2 ,(caddr y) ,(cons 'funcall (cons x (cadr y))))))
((eqcar y 'after)
`(lambda ,(cadr y)
(prog1 ,(cons 'funcall (cons x (cadr y))) ,(caddr y))))))
(/embedreply))
(defun /embedreply ()
(if (atom (embedded)) '(|none| |embedded|)
(append (embedded) (list '|embedded|))))
(defparameter mdeftrace nil "")
(defun /mdef (x)
(let (u)
(cond ((atom x) x)
((or (null (atom (car x))) (not (mbpip (car x))))
(mapcar #'/mdef x))
((equal x (setq u (mdef (car x) x))) x)
(mdeftrace (print x) (princ " --> ") (print u) (/mdef u))
((/mdef u)))))
(defun trargprint (l) (mapc #'(lambda (x) (princ " / ") (prin1 x)) l))
(defun trblanks (n) (do ((i 1 (1+ i))) ((> i n)) (princ " ")))
; 5. Routines for inspecting and resetting total I/O system state
;
; The package largely assumes that:
;
; A. One I/O stream pair is in effect at any moment.
; B. There is a Current Line
; C. There is a Current Token and a Next Token
; D. There is a Reduction Stack
;
; This state may be examined and reset with the procedures IOSTAT and IOCLEAR.
(defun IOStat ()
"Tell me what the current state of the parsing world is."
(current-line-show)
(if $SPAD (next-lines-show))
(token-stack-show)
nil)
(defun IOClear (&optional (in t) (out t))
;(IOStreams-clear in out)
(input-clear)
(current-line-clear)
(token-stack-clear)
(|reduceStackClear|)
(if $SPAD (next-lines-clear))
nil)
;; auxiliary functions needed by the parser
(defun char-eq (x y) (char= (character x) (character y)))
(defun char-ne (x y) (char/= (character x) (character y)))
(Defun FLOATEXPID (X &aux S)
(if (AND (IDENTP X) (char= (char-upcase (ELT (SETQ S (PNAME X)) 0)) #\E)
(> (LENGTH S) 1)
(SPADREDUCE AND 0 (COLLECT (STEP I 1 1 (MAXINDEX S))
(DIGITP (ELT S I)))))
(READ-FROM-STRING S t nil :start 1)
NIL))
(defun |getToken| (x) (if (EQCAR x '|elt|) (third x) x))
(defun |dollarTran| (dom rand)
(let ((eltWord (if |$InteractiveMode| '|$elt| '|elt|)))
(if (and (not (atom rand)) (cdr rand))
(cons (list eltWord dom (car rand)) (cdr rand))
(list eltWord dom rand))))
|