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;; -*- mode: common-lisp -*-
#|
clasm-6502: An assembler for the 6502 written in Common Lisp.
Copyright (C) 2024 Aleksei Eaves
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|#
(setf
*source-file*
(open "/home/aleksei/lisp/wozmon.s"))
(setf
*source-line-number*
0)
(defun interpret-character (s x)
"Interpret meanings of characters."
(cond
((>= x (length s))
'end-of-line)
(t
;; Have character, interpret
(let ((c (char s x)))
(cond
((eq c #\;) ; Comment
'comment)
((eq c #\ ) ; Space
'whitespace)
(t
'normal))))))
(defun extract-word (line-string index)
"Extract a single word from line-string, starting at index."
(cond
((member (interpret-character line-string index)
`(end-of-line comment))
'end-of-line)
((equal (interpret-character line-string index)
'whitespace)
'whitespace)
(t
(subseq
line-string
index
(do ((end index (incf end)))
((not (equal 'normal
(interpret-character line-string end)))
end))))))
(defun extract-words (line-string &optional (index 0))
"Return a list the constituent word strings of line-string."
;; Word Processing Logic
(let ((word (extract-word line-string index)))
(cond
;; Terminate execution at end-of-line.
((equal word 'end-of-line)
nil)
;; If empty, continue on.
((equal word 'whitespace)
(extract-words line-string (+ index 1)))
;; Otherwise, extract word and move ahead.
(t
(cons word
(extract-words line-string
(+ index
(length word))))))))
(defun last-char (s)
(char s (- (length s) 1)))
(defun label? (s)
(eq (last-char s) #\:))
(setf
*grammar*
(('label
(lambda (l)
))))
(defun read_code ()
(incf *source-line-number*)
()
)
|
