miniscm: add mutable string emulation and char->integer

1 files changed, 39 insertions, 0 deletions

diff --git a/miniscm/init.scm b/miniscm/init.scm
index 6db7145..c3f5612 100644
--- a/miniscm/init.scm
+++ b/miniscm/init.scm
@@ -1,6 +1,8 @@
 ; This is a init file for Mini-Scheme.
 ; Modified for UNSLISP.
 
+(define modulo remainder)
+
 (define (caar x) (car (car x)))
 (define (cadr x) (car (cdr x)))
 (define (cdar x) (cdr (car x)))
@@ -48,6 +50,16 @@
 (define vector-ref list-ref)
 (define vector-set! list-set!)
 
+(define make-vector
+  (lambda (num)
+    (letrec
+        ((loop
+          (lambda (iter cell)
+            (if (= iter 0)
+                cell
+                (loop (- iter 1) (cons #f cell))))))
+      (loop num '()))))
+
 (define (head stream) (car stream))
 
 (define (tail stream) (force (cdr stream)))
@@ -75,3 +87,30 @@
          (equal? (cdr x) (cdr y)))
     (and (not (pair? y))
          (eqv? x y))))
+
+;;; Emulation of mutable strings.
+
+(define string-ref list-ref)
+(define string-set! list-set!)
+(define string list)
+
+(define list<=>
+  (lambda (x y <=>)
+    (cond
+      ((and (null? x) (null? y)) '=)
+      ((null? x) '<)
+      ((null? y) '>)
+      (else
+       (let ((dir (<=> (car x) (car y))))
+         (if (eq? dir '=)
+             (list<=> (cdr x) (cdr y) <=>)
+             dir))))))
+
+(define string<=>
+  (lambda (x y)
+    (list<=> x y (lambda (x y)
+                   (if (eqv? x y)
+                       '=
+                       (if (< (char->integer x) (char->integer y))
+                           '<
+                           '>))))))