cl-scopes/forge/forge.lisp

158 lines
3.8 KiB
Common Lisp

;;; cl-scopes/forge - may the forge be with you!
;;;; A Forth-like interpreter implemented in Common Lisp.
(defpackage :scopes/forge
(:use :common-lisp)
(:export #:*forge-env*
#:forge-env #:dstack #:exec #:exec-str #:repl
#:make-iseq #:isq-all #:isq-cur #:isq-next #:isq-end #:isq-add))
(defpackage :sf-builtin)
(defpackage :sf-user)
(in-package :scopes/forge)
;;; iseq: iterable sequence
(defclass iseq ()
((start :reader start :initform (list nil) :initarg :start)
(cur :accessor cur)
(end :accessor end)))
(defun make-iseq (&optional start)
(let* ((start (cons nil start))
(seq (make-instance 'iseq :start start)))
(setf (cur seq) (setf (end seq) start))
seq))
(defun isq-all (seq)
(cdr (start seq)))
(defun isq-cur (seq)
(car (cur seq)))
(defun isq-end (seq)
(car (end seq)))
(defun isq-next (seq)
(pop (cur seq))
(car (cur seq)))
(defun isq-add (seq v)
(setf (cdr (end seq)) (list v))
(pop (end seq)))
;;; forge environment
(defclass forge-env ()
((data-stack :initform nil :accessor data-stack)
(words :initform (make-hash-table))
(comp-words :initform (make-hash-table))
(packages :initform '(:sf-user :sf-builtin))
(current-package :initform :sf-user)
(rp :initform (make-iseq))
(cp :initform (make-iseq))
(ip :initform (make-iseq))))
(defun forge-env ()
(let ((fe (make-instance 'forge-env)))
fe))
(defvar *forge-env* (forge-env))
(defun dstack()
(data-stack *forge-env*))
(defun define-comp-word (sym fn)
(setf (gethash sym (slot-value *forge-env* 'comp-words)) fn))
(defun register (p sym fn)
(let ((w (intern (string sym) p)))
(setf (gethash w (slot-value *forge-env* 'words)) fn)))
;;; builtins
(defun reg-b (sym fn)
(register :sf-builtin sym fn))
(reg-b 'add #'(lambda () (pushd (+ (popd) (popd)))))
(reg-b 'dup #'(lambda () (pushd (car (dstack)))))
(defvar lit #'(lambda () (pushd (isq-next (fip)))))
(reg-b 'lit lit)
(define-comp-word 'def
#'(lambda ()
(let* ((name (isq-next (frp)))
(code (isq-next (frp))))
(print name)
(print code)
;(eval `(defvar ,name (comp code)))
)))
;;; compiler, interpreter
(defun exec-str (s)
(exec (read-from-string
(concatenate 'string "(" s ")"))))
(defun repl ()
(do ((input (read-line) (read-line))) ((string= input "q") nil)
(exec-str input)))
(defun exec (code)
(call (comp code)))
(defun call (code)
(let ((ip (make-iseq code)))
(setf (slot-value *forge-env* 'ip) ip)
(do ((item (isq-next ip) (isq-next ip)))
((null item))
(funcall item))))
(defun comp (slist)
(setf (slot-value *forge-env* 'cp) (make-iseq))
(let ((inp (make-iseq slist)))
(setf (slot-value *forge-env* 'rp) inp)
(do ((item (isq-next inp) (isq-next inp)))
((null item))
(typecase item
(symbol (comp-symbol item))
(cons (comp-item lit) (comp-item (comp item)))
(t (comp-item lit) (comp-item item)))))
(isq-all (fcp)))
(defun comp-symbol (sym)
(let* ((w (get-word sym))
(comp-fn (get-comp-word w)))
(if comp-fn
(funcall comp-fn)
(comp-item (gethash w (slot-value *forge-env* 'words))))))
(defun comp-item (item)
(isq-add (fcp) item))
(defun get-word (sym)
(let ((name (string sym)))
(dolist (p (slot-value *forge-env* 'packages))
(let ((w (find-symbol name p)))
(if w
(return-from get-word w))))
(intern name (slot-value *forge-env* 'current-package))))
(defun get-comp-word (w)
(gethash w (slot-value *forge-env* 'comp-words)))
;;; internal definitions
(defun popd () (pop (data-stack *forge-env*)))
(defun pushd (v) (push v (data-stack *forge-env*)))
(defun frp () (slot-value *forge-env* 'rp))
(defun fcp () (slot-value *forge-env* 'cp))
(defun fip () (slot-value *forge-env* 'ip))