strs
:initial-value ""))
-
-(let ((counter 0))
- (defun make-var-binding (symbol)
- (cons symbol (format nil "v~d" (incf counter)))))
-
-(let ((counter 0))
- (defun make-func-binding (symbol)
- (cons symbol (format nil "f~d" (incf counter)))))
-
-
;;; Concatenate a list of strings, with a separator
(defun join (list separator)
(cond
separator
(join (cdr list) separator)))))
-;;; Compiler
+;;;; Reader
+
+;;; It is a basic Lisp reader. It does not use advanced stuff
+;;; intentionally, because we want to use it to bootstrap a simple
+;;; Lisp. The main entry point is the function `ls-read', which
+;;; accepts a strings as argument and return the Lisp expression.
+(defun make-string-stream (string)
+ (cons string 0))
+
+(defun %peek-char (stream)
+ (if (streamp stream)
+ (peek-char nil stream nil)
+ (and (< (cdr stream) (length (car stream)))
+ (char (car stream) (cdr stream)))))
+
+(defun %read-char (stream)
+ (if (streamp stream)
+ (read-char stream nil)
+ (and (< (cdr stream) (length (car stream)))
+ (prog1 (char (car stream) (cdr stream))
+ (incf (cdr stream))))))
+
+(defun whitespacep (ch)
+ (or (char= ch #\space) (char= ch #\newline) (char= ch #\tab)))
+
+(defun skip-whitespaces (stream)
+ (loop for ch = (%peek-char stream)
+ while (and ch (whitespacep ch))
+ do (%read-char stream)))
+
+(defun terminalp (ch)
+ (or (null ch) (whitespacep ch) (char= #\) ch)))
+
+(defun read-until (stream func)
+ (let ((string ""))
+ (loop for ch = (%peek-char stream)
+ until (funcall func ch)
+ do (setq string (concat string (string ch)))
+ do (%read-char stream))
+ string))
+
+(defun skip-whitespaces-and-comments (stream)
+ (let (ch)
+ (skip-whitespaces stream)
+ (setq ch (%peek-char stream))
+ (while (and ch (eql ch #\;))
+ (read-until stream (lambda (x) (eql x #\newline)))
+ (skip-whitespaces stream)
+ (setq ch (%peek-char stream)))))
+
+(defun %read-list (stream)
+ (skip-whitespaces-and-comments stream)
+ (let ((ch (%peek-char stream)))
+ (cond
+ ((char= ch #\))
+ (%read-char stream)
+ nil)
+ ((char= ch #\.)
+ (%read-char stream)
+ (skip-whitespaces-and-comments stream)
+ (prog1 (ls-read stream)
+ (unless (char= (%read-char stream) #\))
+ (error "')' was expected."))))
+ (t
+ (cons (ls-read stream) (%read-list stream))))))
+
+(defvar *eof* (make-symbol "EOF"))
+(defun ls-read (stream)
+ (skip-whitespaces-and-comments stream)
+ (let ((ch (%peek-char stream)))
+ (cond
+ ((null ch)
+ *eof*)
+ ((char= ch #\()
+ (%read-char stream)
+ (%read-list stream))
+ ((char= ch #\')
+ (%read-char stream)
+ (list 'quote (ls-read stream)))
+ ((char= ch #\`)
+ (%read-char stream)
+ (list 'backquote (ls-read stream)))
+ ((char= ch #\")
+ (%read-char stream)
+ (prog1 (read-until stream (lambda (ch) (char= ch #\")))
+ (%read-char stream)))
+ ((char= ch #\,)
+ (%read-char stream)
+ (if (eql (%peek-char stream) #\@)
+ (progn (%read-char stream) (list 'unquote-splicing (ls-read stream)))
+ (list 'unquote (ls-read stream))))
+ ((char= ch #\#)
+ (%read-char stream)
+ (ecase (%read-char stream)
+ (#\'
+ (list 'function (ls-read stream)))))
+ (t
+ (let ((string (read-until stream #'terminalp)))
+ (if (every #'digit-char-p string)
+ (parse-integer string)
+ (intern (string-upcase string))))))))
+
+(defun ls-read-from-string (string)
+ (ls-read (make-string-stream string)))
+
+
+;;;; Compiler
+
+(let ((counter 0))
+ (defun make-var-binding (symbol)
+ (cons symbol (format nil "v~d" (incf counter)))))
+
+(let ((counter 0))
+ (defun make-func-binding (symbol)
+ (cons symbol (format nil "f~d" (incf counter)))))
(defvar *compilations* nil)
nil
*eval-when-compilations*))
-
(defmacro define-transformation (name args form)
`(define-compilation ,name ,args
(ls-compile ,form env fenv)))
`((lambda ,(mapcar 'car bindings) ,@body)
,@(mapcar 'cadr bindings)))
-;;; aritmetic primitives
+;;; A little backquote implementation without optimizations of any
+;;; kind for lispstrack.
+(defun backquote-expand-1 (form)
+ (cond
+ ((symbolp form)
+ (list 'quote form))
+ ((atom form)
+ form)
+ ((eq (car form) 'unquote)
+ (car form))
+ ((eq (car form) 'backquote)
+ (backquote-expand-1 (backquote-expand-1 (cadr form))))
+ (t
+ (cons 'append
+ (mapcar (lambda (s)
+ (cond
+ ((and (listp s) (eq (car s) 'unquote))
+ (list 'list (cadr s)))
+ ((and (listp s) (eq (car s) 'unquote-splicing))
+ (cadr s))
+ (t
+ (list 'list (backquote-expand-1 s)))))
+ form)))))
+
+(defun backquote-expand (form)
+ (if (and (listp form) (eq (car form) 'backquote))
+ (backquote-expand-1 (cadr form))
+ form))
+
+;;; Some Tests comparing backquote agains the backquote of the host
+;;; Lisp. It is not very exhaustive, but we just want a working
+;;; backquotation to be able bootstrap this program.
+(macrolet ((test (form1 form2)
+ `(assert (equal ,form1 ,form2))))
+ (test (backquote (1 2 3 4))
+ `(1 2 3 4))
+ (test (backquote (1 2 (+ 3 4)))
+ `(1 2 (+ 3 4)))
+ (test (backquote (1 2 (unquote (+ 3 4))))
+ `(1 2 ,(+ 3 4)))
+ (test (backquote (1 2 (unquote-splicing '(3 4))))
+ `(1 2 ,@'(3 4)))
+ (test (backquote (backquote x))
+ ``x)
+ (let ((x 10))
+ (test `',x
+ (backquote (quote (unquote x)))))
+ (let ((x 10))
+ (test (eval ``(,,x))
+ (eval (backquote (backquote ((unquote (unquote x)))))))))
+
+(define-transformation backquote (form)
+ (backquote-expand-1 form))
+
+;;; Primitives
+
(define-compilation + (x y)
(concat "((" (ls-compile x env fenv) ") + (" (ls-compile y env fenv) "))"))
code)
(setq *literals* nil))))
-
(defun ls-compile-file (filename output)
(with-open-file (in filename)
(with-open-file (out output :direction :output :if-exists :supersede)
(loop
- for x = (read in nil) while x
+ for x = (ls-read in)
+ until (eq x *eof*)
for compilation = (ls-compile-toplevel x)
when compilation do (write-line (concat compilation "; ") out)))))
;;; Testing
-
(defun compile-test ()
(ls-compile-file "test.lisp" "test.js"))
projects / jscl.git / blobdiff