From ddca30271e96273577d9f937e98885223f8ccb68 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Mon, 12 Dec 2016 15:41:48 +0100
Subject: [PATCH] Resurrect Mes in Guile.

* guile/mes.mes: New file, from the archives.
* guile/mes.scm: Updates.
---
 guile/mes.mes | 190 ++++++++++++++++++++++++++++++++++++++++++++++++++
 guile/mes.scm |  58 ++++++++-------
 2 files changed, 222 insertions(+), 26 deletions(-)
 create mode 100644 guile/mes.mes

diff --git a/guile/mes.mes b/guile/mes.mes
new file mode 100644
index 00000000..41e160df
--- /dev/null
+++ b/guile/mes.mes
@@ -0,0 +1,190 @@
+;;; -*-scheme-*-
+
+;;; Mes --- Maxwell Equations of Software
+;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;
+;;; mes.mes: This file is part of Mes.
+;;;
+;;; Mes is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; Mes 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 General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+;; The Maxwell Equations of Software -- John McCarthy page 13
+;; http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf
+
+(define (caar x) (car (car x)))
+(define (cadr x) (car (cdr x)))
+(define (cdar x) (cdr (car x)))
+(define (cddr x) (cdr (cdr x)))
+(define (caadr x) (car (car (cdr x))))
+(define (caddr x) (car (cdr (cdr x))))
+(define (cddar x) (cdr (cdr (car x))))
+(define (cdadr x) (cdr (car (cdr x))))
+(define (cadar x) (car (cdr (car x))))
+(define (cdddr x) (cdr (cdr (cdr x))))
+
+;; Page 12
+(define (pairlis x y a)
+  (cond
+   ((null? x) a)
+   ((atom? x) (cons (cons x y) a))
+   (#t (cons (cons (car x) (car y))
+             (pairlis (cdr x) (cdr y) a)))))
+
+(define (assq x a)
+  (cond
+   ((null? a) #f)
+   ((eq? (caar a) x) (car a))
+   (#t (assq x (cdr a)))))
+
+;; Page 13
+(define (evcon c a)
+  (cond
+   ((null? c) *unspecified*)
+   ;; single-statement cond
+   ;; ((eval (caar c) a) (eval (cadar c) a))
+   ((eval (caar c) a)
+    (cond ((null? (cddar c)) (eval (cadar c) a))
+          (#t (eval (cadar c) a)
+              (evcon
+               (cons (cons #t (cddar c)) '())
+               a))))
+   (#t (evcon (cdr c) a))))
+
+(define (evlis m a)
+  (cond
+   ((null? m) '())
+   (#t (cons (eval (car m) a) (evlis (cdr m) a)))))
+
+
+(define (apply-env fn x a) 
+  (cond
+   ((atom? fn)
+    (cond
+     ((eq? fn 'current-module)
+      (c:apply-env current-module '() a))
+     ((eq? fn 'call-with-values)
+      (c:apply-env 'call-with-values x a))
+     ((builtin? fn)
+      (call fn x))
+     (#t (apply-env (eval fn a) x a))))
+   ((eq? (car fn) 'lambda)
+    (begin-env (cddr fn) (pairlis (cadr fn) x a)))
+   ((eq? (car fn) 'label) (apply-env (caddr fn) x (cons (cons (cadr fn)
+                                                         (caddr fn)) a)))))
+
+(define (begin-env body a)
+  (cond ((null? body) *unspecified*)
+        ((null? (cdr body)) (eval (car body) a))
+        (#t (eval (car body) a)
+            (begin-env (cdr body) a))))
+
+(define (set-env! x e a)
+  (set-cdr! (assq x a) e))
+
+(define (eval e a)
+  (cond
+   ((eq? e #t) #t)
+   ((eq? e #f) #f)
+   ((char? e) e)
+   ((number? e) e)
+   ((string? e) e)
+   ((vector? e) e)
+   ((atom? e) (cdr (assq e a)))
+   ((builtin? e) e)
+   ((atom? (car e))
+    (cond
+     ((eq? (car e) 'quote) (cadr e))
+     ((eq? (car e) 'begin) (begin-env (cdr e) a))
+     ((eq? (car e) 'lambda) e)
+     ((eq? (car e) 'set!) (set-env! (cadr e) (caddr e) a))
+     ((eq? (car e) 'unquote) (eval (cadr e) a))
+     ((eq? (car e) 'quasiquote) (eval-quasiquote (cadr e) a))
+     ((eq? (car e) 'cond) (evcon (cdr e) a))
+     ((pair? (assq (car e) (cdr (assq '*macro* a))))
+      (c:eval
+       (c:apply-env
+        (cdr (assq (car e) (cdr (assq '*macro* a))))
+        (cdr e)
+        a)
+       a))
+     (#t (apply-env (car e) (evlis (cdr e) a) a))))
+   (#t (apply-env (car e) (evlis (cdr e) a) a))))
+
+(define (eval-quasiquote e a)
+  (cond ((null? e) e)
+        ((atom? e) e)
+        ((atom? (car e)) (cons (car e) (eval-quasiquote (cdr e) a)))
+        ((eq? (caar e) 'unquote) (cons (eval (cadar e) a) '()))
+        ((eq? (caar e) 'quote) (cons (cadar e) '()))
+        ((eq? (caar e) 'quasiquote) (cons (cadar e) '()))
+        (#t (cons (car e) (eval-quasiquote (cdr e) a)))))
+
+(define (readenv a)
+  (readword (read-byte) '() a))
+
+(define (readword c w a)
+  (cond ((eq? c -1) ;; eof
+         (cond ((eq? w '()) '())
+               (#t (lookup w a))))
+        ((eq? c 10) ;; \n
+         (cond ((eq? w '()) (readword (read-byte) w a))
+               ;; DOT ((eq? w '(*dot*)) (car (readword (read-byte) '() a)))
+               (#t (lookup w a))))
+        ((eq? c 32) ;; \space
+         (readword 10 w a))
+        ((eq? c 40) ;; (
+         (cond ((eq? w '()) (readlist a))
+               (#t (unread-byte c) (lookup w a))))
+        ((eq? c 41) ;; )
+         (cond ((eq? w '()) (unread-byte c) w)
+               (#t (unread-byte c) (lookup w a))))
+        ((eq? c 39) ;; '
+         (cond ((eq? w '())
+                (cons (lookup (cons c '()) a)
+                      (cons (readword (read-byte) w a) '())))
+               (#t (unread-byte c) (lookup w a))))
+        ((eq? c 59) ;; ;
+         (readcomment c)
+         (readword 10 w a))
+        ((eq? c 35) ;; #
+         (cond ((eq? (peek-byte) 33) ;; !
+                (read-byte)
+                (readblock (read-byte))
+                (readword 10 w a))
+               ;; TODO: char, vector
+               (#t (readword (read-byte) (append2 w (cons c '())) a))))
+        (#t (readword (read-byte) (append2 w (cons c '())) a))))
+
+(define (readblock c)
+  (cond ((eq? c 33) (cond ((eq? (peek-byte) 35) (read-byte))
+                         (#t (readblock (read-byte)))))
+        (#t (readblock (read-byte)))))
+
+(define (eat-whitespace)
+  (cond ((eq? (peek-byte) 10) (read-byte) (eat-whitespace))
+        ((eq? (peek-byte) 32) (read-byte) (eat-whitespace))
+        ((eq? (peek-byte) 35) (read-byte) (eat-whitespace))
+        (#t #t)))
+
+(define (readlist a)
+  (eat-whitespace)
+  (cond ((eq? (peek-byte) 41) ;; )
+         (read-byte)
+         '())
+        ;; TODO *dot*
+        (#t (cons (readword (read-byte) '() a) (readlist a)))))
+
+(define (readcomment c)
+  (cond ((eq? c 10) ;; \n
+         c)
+        (#t (readcomment (read-byte)))))
diff --git a/guile/mes.scm b/guile/mes.scm
index 2794b077..df50b988 100755
--- a/guile/mes.scm
+++ b/guile/mes.scm
@@ -1,6 +1,6 @@
 #! /bin/sh
 # -*-scheme-*-
-exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
+exec guile -L $(pwd) -e '(mes)' -s "$0" "$@"
 !#
 
 ;;; Mes --- The Maxwell Equations of Software
@@ -49,7 +49,7 @@ exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
                                 module-define!
                                 resolve-interface
 
-                                ;; PRIMITIVES
+                                ;; PRIMITIVE BUILTINS
                                 car
                                 cdr
                                 cons
@@ -57,9 +57,17 @@ exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
                                 null?
                                 pair?
 
-                                ;; ADDITIONAL PRIMITIVES
+                                ;; READER
+                                char->integer
+                                integer->char
+                                read-char
+                                unread-char
+                                
+                                ;; non-primitive BUILTINS
+                                char?
                                 number?
                                 procedure?
+                                string?
                                 <
                                 -
                                 )
@@ -94,37 +102,35 @@ exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
 (define null? guile:null?)
 (define pair? guile:pair?)
 (define builtin? guile:procedure?)
+(define char? guile:char?)
 (define number? guile:number?)
+(define string? guile:number?)
 (define call guile:apply)
+(define (peek-byte)
+  (unread-byte (read-byte)))
+(define (read-byte)
+  (guile:char->integer (guile:read-char)))
+(define (unread-byte x)
+  (guile:unread-char (guile:integer->char x))
+  x)
+(define (lookup x a)
+  ;; TODO
+  (stderr "lookup x=~a\n" x)
+  x)
 
-(include-from-path "mes/mes.mes")
+(include "mes.mes")
 
-(define (pairlis x y a)
-  ;;(debug "pairlis x=~a y=~a a=~a\n" x y a)
-  (cond
-   ((null? x) a)
-   ((atom? x) (cons (cons x y) a))
-   (#t (cons (cons (car x) (car y))
-             (pairlis (cdr x) (cdr y) a)))))
-
-(define (assq x a)
-  ;;(stderr "assq x=~a\n" x)
-  ;;(debug "assq x=~a a=~a\n" x a)
-  (cond
-   ((null? a) #f)
-   ((eq? (caar a) x) (car a))
-   (#t (assq x (cdr a)))))
-
-(define (append x y)
+(define (append2 x y)
   (cond ((null? x) y)
-        (#t (cons (car x) (append (cdr x) y)))))
+        (#t (cons (car x) (append2 (cdr x) y)))))
 
 (define (eval-environment e a)
-  (eval e (append a environment)))
+  (eval e (append2 a environment)))
 
 (define (apply-environment fn e a)
-  (apply-env fn e (append a environment)))
+  (apply-env fn e (append2 a environment)))
 
+;; READER: TODO lookup
 (define (readenv a)
   (let ((x (guile:read)))
     (if (guile:eof-object? x) '()
@@ -180,7 +186,7 @@ exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
     (cddar . ,cddar)
     (cdddr . ,cdddr)
 
-    (append . ,append)
+    (append2 . ,append2)
     (exit . ,guile:exit)
 
     (*macro* . ())
@@ -215,7 +221,7 @@ exec guile -L $(pwd)/module -e '(mes)' -s "$0" "$@"
         (#t (loop (eval e a) (readenv a) a))))
 
 (define (main arguments)
-  (let ((a (append environment `((*a* . ,environment)))))
+  (let ((a (append2 environment `((*a* . ,environment)))))
     ;;(guile:display (eval (readenv a) a))
     (guile:display (loop *unspecified* (readenv a) a))
     )