adding missing files

lib/scheme/char.scm

@@ -0,0 +1,17 @@
+
+;; Simple ASCII definitions, need to make Unicode aware.
+
+(define char-foldcase char-downcase)
+
+(define (numeric-digit ch)
+  (let ((n (- (char->integer ch) (char->integer #\0))))
+    (and (<= 0 n 9) n)))
+
+(define (string-upcase str)
+  (string-map char-upcase str))
+
+(define (string-downcase str)
+  (string-map char-downcase str))
+
+(define (string-foldcase str)
+  (string-map char-foldcase str))

lib/scheme/division.scm

@@ -0,0 +1,43 @@
+
+(define truncate-quotient quotient)
+(define truncate-remainder remainder)
+(define (truncate/ n m)
+  (values (truncate-quotient n m) (truncate-remainder n m)))
+
+(define floor-remainder modulo)
+(define (floor-quotient n m)
+  (quotient (- n (floor-remainder n m)) m))
+(define (floor/ n m)
+  (values (floor-quotient n m) (floor-remainder n m)))
+
+(define (round-quotient n m)
+  (inexact->exact (round (/ n m))))
+(define (round-remainder n m)
+  (- n (* m (round-quotient n m))))
+(define (round/ n m)
+  (values (round-quotient n m) (round-remainder n m)))
+
+(define (ceiling-quotient n m)
+  (inexact->exact (ceiling (/ n m))))
+(define (ceiling-remainder n m)
+  (- n (* m (ceiling-quotient n m))))
+(define (ceiling/ n m)
+  (values (ceiling-quotient n m) (ceiling-remainder n m)))
+
+(define (euclidean/ n m)
+  (if (> n 0) (ceiling/ n m) (floor/ n m)))
+(define (euclidean-quotient n m)
+  (if (> n 0) (ceiling-quotient n m) (floor-quotient n m)))
+(define (euclidean-remainder n m)
+  (if (> n 0) (ceiling-remainder n m) (floor-remainder n m)))
+
+(define (centered-remainder n m)
+  (let ((r (euclidean-remainder n m))
+        (m/2 (abs (/ m 2))))
+    (cond ((< r (- m/2)) (+ r (abs m)))
+          ((>= r m/2) (- r (abs m)))
+          (else r))))
+(define (centered-quotient n m)
+  (quotient (- n (centered-remainder n m)) m))
+(define (centered/ n m)
+  (values (centered-quotient n m) (centered-remainder n m)))