Added display primitives.

[scheme.forth.jl.git] / scheme-library.scm

diff --git a/scheme-library.scm b/scheme-library.scm
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+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Standard Library Procedures and Macros ;; 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; LISTS
+
+(define (null? args)
+  (eq? args ()))
+
+; Join two lists together
+(define (join l1 l2)
+  (if (null? l1)
+    l2
+    (cons (car l1) (join (cdr l1) l2))))
+
+; Append an arbitrary number of lists together
+(define (append . lists)
+  (if (null? lists)
+    ()
+    (if (null? (cdr lists))
+      (car lists)
+      (join (car lists) (apply append (cdr lists))))))
+
+
+;; LIBRARY FORMS
+(define-macro (let value . body )
+              (list (list 'lambda (list (car value)) body)) (cdr value))
+
+;; TESTING
+
+; Basic iterative summation.  Run this on large numbers to
+; test garbage collection and tail-call optimization.
+(define (sum n)
+
+  (define (sum-iter total count maxcount)
+    (if (> count maxcount)
+      total
+      (sum-iter (+ total count) (+ count 1) maxcount)))
+  
+  (sum-iter 0 1 n))
+
+; Recursive summation. Use this to compare with tail call
+; optimized iterative algorithm.
+(define (sum-recurse n)
+  (if (= n 0)
+    0
+    (+ n (sum-recurse (- n 1)))))