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;; Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
;; 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: MetaLex.lisp
; PURPOSE: Parsing support routines for Meta code
; CONTENTS:
;
; 1. META File Handling
; 2. META Line Handling
; 3. META Token Handling
; 4. META Token Parsing Actions
; 5. META Error Handling
(in-package "BOOT")
; *** 2. META Line Handling
(defun next-META-line (&optional (in-stream t))
"Get next line, trimming trailing blanks and trailing comments.
One trailing blank is added to a non-blank line to ease between-line
processing for Next Token (i.e., blank takes place of return). Returns T
if it gets a non-blank line, and NIL at end of stream."
(prog (string)
empty (if File-Closed (return nil))
(setq string (kill-trailing-blanks (kill-comments
(get-a-line in-stream))))
(if (= (length string) 0) (go empty))
(Line-New-Line (suffix #\Space string) Current-Line)
(if Echo-Meta (Print-New-Line (Line-Buffer Current-Line) out-stream))
(return t)))
(defparameter Comment-Character #\% "Delimiter of comments in Meta code.")
(defun kill-comments (string)
"Deletes from comment character % to end of STRING."
(subseq string 0
(let ((mi (maxindex string)))
(do ((i 0 (1+ i)))
((> i mi) i)
(if (and (char= (elt string i) Comment-Character)
(or (eq i 0) (char/= (elt string (1- i)) #\\)))
(return i))))))
(defun kill-trailing-blanks (string)
"Remove white space from end of STRING."
; Coding note: yes, I know, use string-trim -- but it is broken
; in Symbolics Common Lisp for short strings
(let* ((sl (length string))
(right (if (= sl 0) -1
(or
(position-if-not
#'(lambda (x)
(member x '(#\Space #\Tab #\Newline) :test #'char=))
string :from-end t)
-1))))
(if (>= right 0) (subseq string 0 (1+ right)) (make-string 0))))
; *** 3. META Token Handling
; STRING: "'" { Chars - "'" }* "'"
; BSTRING: "[" ... "]*"
; ID: letters, _ and then numbers
; NUMBER: digits, ., digits, e, +-, digits
(defun-parse-token STRING)
(defun-parse-token BSTRING)
(defun-parse-token IDENTIFIER)
(defun-parse-token NUMBER)
; Meta tokens fall into the following categories:
;
; Number
; Identifier
; Dollar-sign
; Special character
;
; Special characters are represented as characters, numbers as numbers, and
; identifiers as strings. The reason identifiers are represented as strings is
; that the full print-name of the intern of a string depends on the package you
; are currently executing in; this can lead to very confusing results!
(defun get-META-token (token)
(prog nil
loop (if (not (skip-blanks)) (return nil))
(case (token-lookahead-type (current-char))
(id (return (get-identifier-token token)))
(num (return (get-number-token token)))
(string (return (get-string-token token)))
(bstring (return (get-bstring-token token)))
; (dollar (return (get-identifier-token token)))
(special-char (return (get-special-token token)))
(eof (return nil)))))
(defun skip-blanks ()
(loop (let ((cc (current-char)))
(if (not cc) (return nil))
(if (eq (token-lookahead-type cc) 'white)
(if (not (advance-char)) (return nil))
(return t)))))
(defparameter Escape-Character #\\ "Superquoting character.")
(defun token-lookahead-type (char)
"Predicts the kind of token to follow, based on the given initial character."
(cond ((not char) 'eof)
((or (char= char Escape-Character) (alpha-char-p char)) 'id)
((digitp char) 'num)
((char= char #\') 'string)
((char= char #\[) 'bstring)
; ((char= char #\$) (advance-char) 'dollar)
((member char '(#\Space #\Tab #\Return) :test #'char=) 'white)
(t 'special-char)))
(defun make-adjustable-string (n)
(make-array (list n) :element-type 'character :adjustable t))
(defun get-identifier-token (token)
"Take an identifier off the input stream."
(prog ((buf (make-adjustable-string 0)))
id (let ((cur-char (current-char)))
(cond ((equal cur-char Escape-Character)
(if (not (advance-char)) (go bye))
(suffix (current-char) buf)
(if (not (advance-char)) (go bye))
(go id))
((or (alpha-char-p cur-char)
(char= cur-char #\-)
(digitp cur-char)
(char= cur-char #\_))
(suffix (current-char) buf)
(if (not (advance-char)) (go bye))
(go id))))
bye (return (token-install (intern buf) 'identifier token))))
(defun get-string-token (token)
"With 'ABC' on IN-STREAM, extracts and stacks String 'ABC'."
(let ((buf (make-adjustable-string 0)))
(if (char= (current-char) #\')
(progn (advance-char)
(loop (case (current-char)
(#\' (advance-char)
(return (token-install buf 'string token)))
(#\\ (advance-char)
(suffix (current-char) buf)
(advance-char))
(#\Return
(moan "String should fit on one line!")
(advance-char)
(meta-syntax-error)
(return nil))
(t (suffix (current-char) buf)
(advance-char))))))))
(defun get-bstring-token (token)
"With ABC]* on in-stream, extracts and stacks string ABC."
(let ((buf (make-adjustable-string 0)))
(if (char= (current-char) #\[)
(progn (advance-char)
(loop (case (current-char)
(#\] (if (char= (next-char) #\*)
(progn (advance-char)
(advance-char)
(return (token-install buf 'bstring token)))
(progn (suffix (current-char) buf)
(advance-char))))
(#\\ (advance-char)
(suffix (current-char) buf)
(advance-char))
(#\Return
(moan "String should fit on one line!")
(advance-char)
(meta-syntax-error)
(return nil))
(t (suffix (current-char) buf)
(advance-char))))))))
(defun get-special-token (token)
"Take a special character off the input stream. We let the type name of each
special character be the atom whose print name is the character itself."
(let ((symbol (current-char)))
(advance-char)
(token-install symbol 'special-char token)))
(defun get-number-token (token)
"Take a number off the input stream."
(prog ((buf (make-adjustable-string 0)))
nu1 (suffix (current-char) buf) ; Integer part
(let ((next-chr (next-char)))
(cond ((digitp next-chr)
(advance-char)
(go nu1))))
(advance-char)
formint(return (token-install
(read-from-string buf)
'number token
(size buf) ;used to keep track of digit count
))))
; *** 4. META Auxiliary Parsing Actions
(defun make-defun (nametok vars body)
(let ((name (INTERN (STRCONC |META_PREFIX| nametok))))
(if vars
`(DEFUN ,name ,vars (declare (special . ,vars)) ,body)
`(DEFUN ,name ,vars ,body))))
(defun print-fluids (fluids)
(terpri out-stream)
(mapcar #'(lambda (x) (format out-stream "~&(DEFPARAMETER ~S NIL)~%" x)) fluids)
(terpri out-stream))
(defun print-package (package)
(format out-stream "~&~%(IN-PACKAGE ~S )~%~%" package))
(defparameter Meta_Prefix nil)
(defun set-prefix (prefix) (setq META_PREFIX prefix))
(defun print-rule (x) (print x out-stream) (format out-stream "~%~%"))
; *** 5. META Error Handling
(defparameter $num_of_meta_errors 0)
(defun meta-meta-error-handler (&optional (wanted nil) (parsing nil))
"Print syntax error indication, underline character, scrub line."
(format out-stream "~&% MetaLanguage syntax error: ")
(if (Line-Past-End-P Current-Line)
(cond ((and wanted parsing)
(format out-stream "wanted ~A while parsing ~A.~%"
wanted parsing))
(wanted (format out-stream "wanted ~A.~%" wanted))
(parsing (format out-stream "while parsing ~A.~%" parsing)))
(progn (format out-stream "~:[here~;wanted ~A here~]" wanted wanted)
(format out-stream "~:[~; while parsing ~A~]:~%" parsing parsing)
(current-line-print)
(current-line-clear)
(current-token)
(incf $num_of_meta_errors)
(setq Meta_Errors_Occurred t)))
nil)
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