105 lines
2.3 KiB
Common Lisp
105 lines
2.3 KiB
Common Lisp
;;; cl-scopes/forge - may the forge be with you!
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;;;; A Forth-like interpreter implemented in Common Lisp.
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(defpackage :scopes/forge
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(:use :common-lisp)
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(:export #:*forge-env*
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#:forge-env #:dstack #:exec #:exec-str #:repl
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#:make-iseq #:isq-all #:isq-cur #:isq-next #:isq-end #:isq-add
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#:add))
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(in-package :scopes/forge)
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;;; builtins
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(defvar add #'(lambda () (pushd (cl:+ (popd) (popd)))))
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(defvar lit #'(lambda () (pushd (isq-next (ip *forge-env*)))))
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;;; iseq: iterable sequence
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(defclass iseq ()
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((start :reader start :initform (list nil) :initarg :start)
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(cur :accessor cur)
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(end :accessor end)))
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(defun make-iseq (&optional start)
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(let* ((start (cons nil start))
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(seq (make-instance 'iseq :start start)))
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(setf (cur seq) (setf (end seq) start))
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seq))
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(defun isq-all (seq)
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(cdr (start seq)))
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(defun isq-cur (seq)
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(car (cur seq)))
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(defun isq-end (seq)
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(car (end seq)))
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(defun isq-next (seq)
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(pop (cur seq))
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(car (cur seq)))
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(defun isq-add (seq v)
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(setf (cdr (end seq)) (list v))
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(pop (end seq)))
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(defclass forge-env ()
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((data-stack :initform nil
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:accessor data-stack)
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(cp :initform (make-iseq)
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:accessor cp)
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(ip :initform (make-iseq)
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:accessor ip)))
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;;; forge environment
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(defun forge-env ()
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(let ((fe (make-instance 'forge-env)))
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fe))
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(defvar *forge-env* (forge-env))
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(defun dstack()
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(data-stack *forge-env*))
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(defun exec-str (s)
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(exec (read-from-string
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(concatenate 'string "(" s ")"))))
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(defun repl ()
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(do ((input (read-line) (read-line))) ((string= input "q") nil)
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(exec-str input)))
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(defun exec (code)
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(call (comp code)))
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(defun call (code)
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(let ((ip (make-iseq code)))
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(setf (ip *forge-env*) ip)
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(do ((item (isq-next ip) (isq-next ip)))
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((null item))
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(funcall item))))
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(defun comp (slist)
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(setf (cp *forge-env*) (make-iseq))
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(let ((inp (make-iseq slist)))
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(do ((item (isq-next inp) (isq-next inp)))
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((null item))
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(typecase item
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(symbol (comp1 (symbol-value item)))
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(cons (comp1 lit) (comp1 (comp item)))
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(t (comp1 lit) (comp1 item)))))
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(isq-all (cp *forge-env*)))
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(defun comp1 (item)
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(isq-add (cp *forge-env*) item))
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;;; internal definitions
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(defun popd () (pop (data-stack *forge-env*)))
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(defun pushd (v) (push v (data-stack *forge-env*)))
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