subseq, substr, sublist + test 034; doseq with start & end

Fundamental.lisp

@@ -152,24 +152,49 @@
     (eval resultform)))
 
 (defspecial doseq (formargs &rest body)
-  "(doseq (loopvar seq resultform) . body)"
-  (let ((var (car formargs))
-        (seq (eval (cadr formargs)))
-        resultform)
-    (let ((list (if (stringp seq)
-                    (split-string "" seq)
-                  seq)))
-      (when (consp (cddr formargs))
-        (setq resultform (caddr formargs)))
-      (while (consp list)
-        (set var (pop list))
+  "(doseq (loopvar seq [resultform [start [end]]]) . body)"
+  (let* ((var (car formargs))
+         (start (or (cadddr formargs) 0))
+         (end (car (cddddr formargs)))
+         (seq (eval (subseq (cadr formargs) start )))
+         ((resultform (caddr formargs)))
+         ((doseq-list (if (stringp seq)
+                          (split-string "" seq)
+                        seq))))
+      (while (consp doseq-list)
+        (set var (pop doseq-list))
         (eval-list body))
-      (eval resultform))))
+      (eval resultform)))
 
 (defun sequencep (object)
   "return t if OBJECT is a sequence (list or string), nil else"
   (or (listp object) (stringp object)))
 
+(defun sublist (l start &optional end)
+  "return a sublist of L bounded by START end END"
+  ;; (format t "(sublist %s %s %s)\n" l start end)
+  (if (null l)
+      nil
+    (if (null end)
+        (if (<= start 0)
+            l
+          (sublist (cdr l) (1- start)))
+      (if (<= end 0)
+          nil
+        (if (<= start 0)
+            (cons (car l)
+                  (sublist (cdr l) 0 (1- end)))
+          (sublist (cdr l) (1- start) (1- end)))))))
+
+(defun substr (str start &optional end)
+  "return a substring of STR bounded by START end END"
+  (apply #'string (sublist (split-string str "") start end)))
+
+(defun subseq (seq start &optional end)
+  "return a copy of the subsequence of SEQ bounded by START and END"
+  (cond ((listp seq) (sublist seq start end))
+        ((stringp seq) (substr seq start end))
+        (t (error "subseq: not a sequence: %s" seq))))
 
 (defun atom (ob)
   "return true if OBJECT is an atom, i.e. not a pair"

tests/034-subseq.lisp

+(testcmp "substr 0" '(sublist '(m a d r i g a l) 0) '(m a d r i g a l))
+(testcmp "sublist 2" '(sublist '(m a d r i g a l) 2) '(d r i g a l))
+(testcmp "sublist 10" '(sublist '(m a d r i g a l) 10) ())
+
+(testcmp "sublist 0 0" '(sublist '(m a d r i g a l) 0 0) ())
+(testcmp "sublist 2 0" '(sublist '(m a d r i g a l) 2 0) ())
+(testcmp "sublist 10 0" '(sublist '(m a d r i g a l) 10 0) ())
+
+(testcmp "sublist 0 1" '(sublist '(m a d r i g a l) 0 1) '(m))
+(testcmp "sublist 2 1" '(sublist '(m a d r i g a l) 2 1) ())
+(testcmp "sublist 10 1" '(sublist '(m a d r i g a l) 10 1) ())
+
+(testcmp "sublist 0 2" '(sublist '(m a d r i g a l) 0 2) '(m a))
+(testcmp "sublist 2 2" '(sublist '(m a d r i g a l) 2 2) ())
+(testcmp "sublist 10 2" '(sublist '(m a d r i g a l) 10 2) ())
+
+(testcmp "sublist 0 5" '(sublist '(m a d r i g a l) 0 5) '(m a d r i))
+(testcmp "sublist 2 5" '(sublist '(m a d r i g a l) 2 5) '(d r i))
+(testcmp "sublist 10 5" '(sublist '(m a d r i g a l) 10 5) ())
+
+(testcmp "sublist 0 15" '(sublist '(m a d r i g a l) 0 15) '(m a d r i g a l))
+(testcmp "sublist 2 15" '(sublist '(m a d r i g a l) 2 15) '(d r i g a l))
+(testcmp "sublist 10 15" '(sublist '(m a d r i g a l) 10 15) ())
+
+
+(testcmp "substr 0" '(substr "madrigal" 0) "madrigal")
+(testcmp "substr 2" '(substr "madrigal" 2) "drigal")
+(testcmp "substr 10" '(substr "madrigal" 10) "")
+
+(testcmp "substr 0 0" '(substr "madrigal" 0 0) "")
+(testcmp "substr 2 0" '(substr "madrigal" 2 0) "")
+(testcmp "substr 10 0" '(substr "madrigal" 10 0) "")
+
+(testcmp "substr 0 1" '(substr "madrigal" 0 1) "m")
+(testcmp "substr 2 1" '(substr "madrigal" 2 1) "")
+(testcmp "substr 10 1" '(substr "madrigal" 10 1) "")
+
+(testcmp "substr 0 2" '(substr "madrigal" 0 2) "ma")
+(testcmp "substr 2 2" '(substr "madrigal" 2 2) "")
+(testcmp "substr 10 2" '(substr "madrigal" 10 2) "")
+
+(testcmp "substr 0 5" '(substr "madrigal" 0 5) "madri")
+(testcmp "substr 2 5" '(substr "madrigal" 2 5) "dri")
+(testcmp "substr 10 5" '(substr "madrigal" 10 5) "")
+
+(testcmp "substr 0 15" '(substr "madrigal" 0 15) "madrigal")
+(testcmp "substr 2 15" '(substr "madrigal" 2 15) "drigal")
+(testcmp "substr 10 15" '(substr "madrigal" 10 15) "")
+