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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: 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
(IMPORT-MODULE "lexing")
(IMPORT-MODULE "macros")
(in-package "BOOT")
; 0. Current I/O Stream definition
(defparameter in-stream t "Current input stream.")
(defparameter out-stream t "Current output stream.")
(defparameter File-Closed nil "Way to stop EOF tests for console input.")
; 1. Data structure declarations (defstructs) for parsing objects
;
; A. Line Buffer
; C. Token
; 1A. A Line Buffer
;
; The philosophy of lines is that
;
; a) NEXT LINE will always get you a non-blank line or fail.
; b) Every line is terminated by a blank character.
;
; Hence there is always a current character, because there is never a non-blank line,
; and there is always a separator character between tokens on separate lines.
; Also, when a line is read, the character pointer is always positioned ON the first
; character.
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Line-Buffer, Line-Current-Char, Line-Current-Index, Line-Last-Index, Line-Number
; Line-New-Line, Line-Advance-Char, Line-Past-End-P, Line-At-End-P
; Make-Line
(defstruct Line "Line of input file to parse."
(Buffer (make-string 0) :type string)
(Current-Char #\Return :type character)
(Current-Index 1 :type fixnum)
(Last-Index 0 :type fixnum)
(Number 0 :type fixnum))
(defun Line-Print (line)
(format out-stream "~&~5D> ~A~%" (Line-Number line) (Line-Buffer Line))
(format out-stream "~v@T^~%" (+ 7 (Line-Current-Index line))))
(defmacro Line-Clear (line)
`(let ((l ,line))
(setf (Line-Buffer l) (make-string 0)
(Line-Current-Char l) #\Return
(Line-Current-Index l) 1
(Line-Last-Index l) 0
(Line-Number l) 0)))
(defun Line-Current-Segment (line)
"Buffer from current index to last index."
(if (line-at-end-p line) (make-string 0)
(subseq (Line-Buffer line)
(Line-Current-Index line)
(Line-Last-Index line))))
(defun Line-New-Line (string line &optional (linenum nil))
"Sets string to be the next line stored in line."
(setf (Line-Last-Index line) (1- (length string))
(Line-Current-Index line) 0
(Line-Current-Char line) (or (and (> (length string) 0) (elt string 0)) #\Return)
(Line-Buffer line) string
(Line-Number line) (or linenum (1+ (Line-Number line)))))
(defun Line-Advance-Char (line)
(setf (Line-Current-Char line)
(elt (Line-Buffer line) (incf (Line-Current-Index line)))))
(defun Line-Next-Char (line)
(elt (Line-Buffer line) (1+ (Line-Current-Index line))))
(defun Line-Past-End-P (line)
"Tests if line is empty or positioned past the last character."
(> (line-current-index line) (line-last-index line)))
(defun Line-At-End-P (line)
"Tests if line is empty or positioned past the last character."
(>= (line-current-index line) (line-last-index line)))
; *** Next Line
(defun make-string-adjustable (s)
(cond ((adjustable-array-p s) s)
(t (make-array (array-dimensions s) :element-type 'character
:adjustable t :initial-contents s))))
(defun get-a-line (stream)
(if (and (IS-CONSOLE stream) (not |$leanMode|))
(|printPrompt|))
(let ((ll (read-a-line stream)))
(if (stringp ll) (make-string-adjustable ll) ll)))
(defparameter Current-Fragment nil
"A string containing remaining chars from readline; needed because
Symbolics read-line returns embedded newlines in a c-m-Y.")
(defun input-clear () (setq Current-Fragment nil))
(defparameter Boot-Line-Stack nil "List of lines returned from PREPARSE.")
(defun Next-Lines-Clear () (setq Boot-Line-Stack nil))
(defun Next-Lines-Show ()
(and Boot-Line-Stack (format t "Currently preparsed lines are:~%~%"))
(mapcar #'(lambda (line)
(format t "~&~5D> ~A~%" (car line) (cdr Line)))
Boot-Line-Stack))
; 3. Routines for handling lexical scanning
;
; Lexical scanning of tokens is performed off of the current line. No
; token can span more than 1 line. All real I/O is handled in a line-oriented
; fashion (in a slight paradox) below the character level. All character
; routines implicitly assume the parameter Current-Line. We do not make
; Current-Line an explicit optional parameter for reasons of efficiency.
(defparameter Current-Line (make-line) "Current input line.")
(defmacro current-line-print () '(Line-Print Current-Line))
(defmacro current-line-show ()
`(if (line-past-end-p current-line)
(format t "~&The current line is empty.~%")
(progn (format t "~&The current line is:~%~%")
(current-line-print))))
(defmacro current-line-clear () `(Line-Clear Current-Line))
(defun read-a-line (&optional (stream t))
(let (cp)
(if (and Current-Fragment (> (length Current-Fragment) 0))
(let ((line (with-input-from-string
(s Current-Fragment :index cp :start 0)
(read-line s nil nil))))
(setq Current-Fragment (subseq Current-Fragment cp))
line)
(prog nil
(if (stream-eof in-stream)
(progn (setq File-Closed t *EOF* t)
(Line-New-Line (make-string 0) Current-Line)
(return nil)))
(if (setq Current-Fragment (read-line stream))
(return (read-a-line stream)))))))
; *** Print New Line
(defparameter Printer-Line-Stack (|makeStack|)
"Stack of output listing lines waiting to print. [local to PRINT-NEW-LINE]")
(defparameter Read-Quietly nil
"Whether or not to produce an output listing. [local to PRINT-NEW-LINE]")
(defun Print-New-Line (string &optional (strm |$OutputStream|))
"Makes output listings."
(if Read-Quietly (|stackPush!| (copy-tree string) Printer-Line-Stack)
(progn (mapc #'(lambda (x) (format strm "; ~A~%" x) (terpri))
(|reverse!| (|stackStore| Printer-Line-Stack)))
(|stackClear!| Printer-Line-Stack)
(format strm "~&; ~A~%" string))))
; 3A (2) Character handling.
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Current-Char, Next-Char, Advance-Char
; *** Current Char, Next Char, Advance Char
(defun Current-Char ()
"Returns the current character of the line, initially blank for an unread line."
(if (Line-Past-End-P Current-Line) #\Return (Line-Current-Char Current-Line)))
(defun Next-Char ()
"Returns the character after the current character, blank if at end of line.
The blank-at-end-of-line assumption is allowable because we assume that end-of-line
is a token separator, which blank is equivalent to."
(if (Line-At-End-P Current-Line) #\Return (Line-Next-Char Current-Line)))
(defun Advance-Char ()
"Advances IN-STREAM, invoking Next Line if necessary."
(loop (cond ((not (Line-At-End-P Current-Line))
(return (Line-Advance-Char Current-Line)))
((next-boot-line in-stream)
(return (current-char)))
((return nil)))))
; 1C. Token
; FUNCTIONS DEFINED IN THIS SECTION:
;
; Make-Token, Token-Symbol, Token-Type, Token-Install, Token-Print
(defstruct Token
"A token is a Symbol with a Type.
The type is either NUMBER, IDENTIFIER or SPECIAL-CHAR.
NonBlank is true if the token is not preceded by a blank."
(Symbol nil)
(Type nil)
(NonBlank t))
(defparameter Prior-Token (make-token) "What did I see last")
(defparameter nonblank t "Is there no blank in front of the current token.")
(defparameter Current-Token (make-token) "Token at head of input stream.")
(defparameter Next-Token (make-token) "Next token in input stream.")
(defparameter Valid-Tokens 0 "Number of tokens in buffer (0, 1 or 2)")
(defun Token-Install (symbol type token &optional (nonblank t))
(setf (token-symbol token) symbol
(token-type token) type
(token-nonblank token) nonblank)
token)
; *** Match Token
(defun match-token (token type &optional (symbol nil))
(if (and token (eq (token-type token) type))
(if symbol (if (equal symbol (token-symbol token)) token) token)))
(defun match-current-token (type &optional (symbol nil))
"Returns the current token if it has EQ type and (optionally) equal symbol."
(match-token (current-token) type symbol))
(defun match-next-token (type &optional (symbol nil))
"Returns the next token if it has equal type and (optionally) equal symbol."
(match-token (next-token) type symbol))
; *** Current Token, Next Token, Advance Token
(defun try-get-token (token)
(let ((tok (get-boot-token token)))
(if tok (progn (incf Valid-Tokens) token))))
(defun current-symbol () (make-symbol-of (current-token)))
(defun make-symbol-of (token)
(let ((u (and token (token-symbol token))))
(cond ((not u) nil)
((characterp u) (intern (string u)))
(u))))
(defun Token-Print (token)
(format out-stream "(token (symbol ~S) (type ~S))~%"
(Token-Symbol token) (Token-Type token)))
(defun current-token ()
"Returns the current token getting a new one if necessary."
(if (> Valid-Tokens 0)
Current-Token
(try-get-token Current-Token)))
(defun next-token ()
"Returns the token after the current token, or NIL if there is none after."
(current-token)
(if (> Valid-Tokens 1)
Next-Token
(try-get-token Next-Token)))
(defun advance-token ()
"Makes the next token be the current token."
(case Valid-Tokens
(0 (try-get-token Current-Token))
(1 (decf Valid-Tokens)
(setq Prior-Token (copy-token Current-Token))
(try-get-token Current-Token))
(2 (setq Prior-Token (copy-token Current-Token))
(setq Current-Token (copy-token Next-Token))
(decf Valid-Tokens))))
(defun reduce-stack-show ()
(let ((store (|stackStore| |$reduceStack|))
(*print-pretty* t))
(if store
(progn (format t "~%Reduction stack contains:~%")
(mapcar #'(lambda (x)
(if (eq (type-of x) 'token)
(describe x)
(print x)))
(|stackStore| |$reduceStack|)))
(format t "~%There is nothing on the reduction stack.~%"))))
; *** 2. META Line Handling
(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
; 3A (1) Token Handling.
; Tokens are acquired from a stream of characters. Lexical analysis is performed
; by the functiond Get Token. One-token lookahead is maintained in variables
; Current-Token and Next-Token by procedures Current Token, Next Token, and
; Advance Token. The functions Match Current Token and Match Next Token recognize
; classes of tokens, by type, or by type and symbol. The current and next tokens
; can be shoved back on the input stream (to the current line) with Unget-Tokens.
(defmacro Defun-Parse-Token (token)
`(defun ,(intern (concatenate 'string "PARSE-" (string token))) ()
(let* ((tok (match-current-token ',token))
(symbol (if tok (token-symbol tok))))
(if tok (progn (|pushReduction|
',(intern (concatenate 'string (string token)
"-TOKEN"))
(copy-tree symbol))
(advance-token)
t)))))
(defun token-stack-show ()
(if (= Valid-Tokens 0) (format t "~%There are no valid tokens.~%")
(format t "~%The number of valid tokens is ~S.~%" Valid-Tokens))
(if (> Valid-Tokens 0)
(progn (format t "The current token is~%")
(describe current-token)))
(if (> Valid-Tokens 1)
(progn (format t "The next token is~%")
(describe next-token)))
(if (token-type prior-token)
(progn (format t "The prior token was~%")
(describe prior-token))))
(defmacro token-stack-clear ()
`(progn (setq valid-tokens 0)
(token-install nil nil current-token nil)
(token-install nil nil next-token nil)
(token-install nil nil prior-token nil)))
; Unget-Tokens
(defun quote-if-string (token)
(if token ;only use token-type on non-null tokens
(case (token-type token)
(bstring (strconc "[" (token-symbol token) "]*"))
(string (strconc "'" (token-symbol token) "'"))
(spadstring (strconc "\"" (underscore (token-symbol token)) "\""))
(number (format nil "~v,'0D" (token-nonblank token)
(token-symbol token)))
(special-char (string (token-symbol token)))
(identifier (let ((id (symbol-name (token-symbol token)))
(pack (package-name (symbol-package
(token-symbol token)))))
(if $SPAD
(if (equal pack "BOOT")
(escape-keywords (underscore id) (token-symbol token))
(concatenate 'string
(underscore pack) "'" (underscore id)))
id)))
(t (token-symbol token)))
nil))
(defconstant Keywords
'(|or| |and| |isnt| |is| |when| |where| |forall| |exist| |try|
|has| |with| |add| |case| |in| |by| |pretend| |mod| |finally|
|exquo| |div| |quo| |else| |rem| |then| |suchthat| |catch| |throw|
|if| |yield| |iterate| |break| |from| |exit| |leave| |return|
|not| |unless| |repeat| |until| |while| |for| |import| |inline|)
"Alphabetic literal strings occurring in the New Meta code constitute
keywords. These are recognized specifically by the AnyId production,
GET-BOOT-IDENTIFIER will recognize keywords but flag them
as keywords.")
(defun escape-keywords (pname id)
(if (member id keywords)
(concatenate 'string "_" pname)
pname))
(defun underscore (string)
(if (every #'alpha-char-p string) string
(let* ((size (length string))
(out-string (make-array (* 2 size)
:element-type 'character
:fill-pointer 0))
next-char)
(dotimes (i size)
(setq next-char (char string i))
(if (not (alpha-char-p next-char))
(vector-push #\_ out-string))
(vector-push next-char out-string))
out-string)))
(defun Unget-Tokens ()
(case Valid-Tokens
(0 t)
(1 (let* ((cursym (quote-if-string current-token))
(curline (line-current-segment current-line))
(revised-line (strconc cursym curline (copy-seq " "))))
(line-new-line revised-line current-line (line-number current-line))
(setq NonBlank (token-nonblank current-token))
(setq Valid-Tokens 0)))
(2 (let* ((cursym (quote-if-string current-token))
(nextsym (quote-if-string next-token))
(curline (line-current-segment current-line))
(revised-line
(strconc (if (token-nonblank current-token) "" " ")
cursym
(if (token-nonblank next-token) "" " ")
nextsym curline " ")))
(setq NonBlank (token-nonblank current-token))
(line-new-line revised-line current-line (line-number current-line))
(setq Valid-Tokens 0)))
(t (error "How many tokens do you think you have?"))))
(defun-parse-token STRING)
(defun-parse-token BSTRING)
(defun-parse-token IDENTIFIER)
(defun-parse-token NUMBER)
; Parsing of operator tokens depends on tables initialized by BOTTOMUP.LISP
(defun-parse-token SPADSTRING)
(defun-parse-token KEYWORD)
(defun-parse-token ARGUMENT-DESIGNATOR)
(defun |PARSE-OperatorFunctionName| ()
(let ((id (make-symbol-of (or (match-current-token 'keyword)
(match-current-token 'gliph)
(match-current-token 'special-char)))))
(when (and id (member id |$OperatorFunctionNames|))
(|pushReduction| '|PARSE-OperatorFunctionName| id)
(action (advance-token)))))
; 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)
(spad_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)
(spad_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)
(return (token-install (read-from-string buf)
'number token
(size buf) ;used to keep track of digit count
))))
; *** 4. META Auxiliary Parsing Actions
(defparameter Meta_Prefix nil)
(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))
(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)
(defparameter Meta_Errors_Occurred nil "Did any errors occur")
|