implement some of important list functions listed on srfi-1

piclib/srfi/1.scm

@@ -5,12 +5,20 @@
   ;; cons list
   ;; xcons cons* make-list list-tabulate
   ;; list-copy circular-list iota
+  (define (xcons a b)
+    (cons b a))
+
+  (export cons list xcons)
 
   ;; # Predicates
   ;; pair? null?
   ;; proper-list? cirtular-list? dotted-list?
   ;; not-pair? null-list?
   ;; list=
+  (define (not-pair? x)
+    (not (pair? x)))
+
+  (export pair? null? not-pair?)
 
   ;; # Selectors
   ;; car cdr ... cddadr cddddr list-ref
@@ -21,6 +29,25 @@
   ;; take! drop-right!
   ;; split-at split-at!
   ;; last last-pair
+  (define (car+cdr pair)
+    (values (car pair) (cdr pair)))
+
+  (define (take x i)
+    (if (zero? i)
+        '()
+        (cons (car x)
+              (take (cdr x) (- i 1)))))
+
+  (define (drop x i)
+    (if (zero? i)
+        x
+        (drop (cdr x) (- i 1))))
+
+  (define (split-at x i)
+    (values (take x i) (drop x i)))
+
+  (export car cdr car+cdr
+          take drop)
 
   ;; # Miscellaneous
   ;; length length+
@@ -29,6 +56,13 @@
   ;; append-reverse append-reverse!
   ;; zip unzip1 unzip2 unzip3 unzip4 unzip5
   ;; count
+  (define (concatenate lists)
+    (apply append lists))
+
+  (define (zip . lists)
+    (apply map list lists))
+
+  (export length append concatenate reverse zip)
 
   ;; # Fold, unfold & map
   ;; map for-each
@@ -36,10 +70,27 @@
   ;; fold-right unfold-right pair-fold right reduce-right
   ;; append-map append-map!
   ;; map! pair-for-each filter-map map-in-order
+  (export map for-each)
 
   ;; # Filtering & partitioning
   ;; filter partition remove
   ;; filter! partition! remove!
+  (define (filter pred list)
+    (if (null? list)
+        '()
+        (if (pred (car list))
+            (cons (car list)
+                  (filter pred (cdr list)))
+            (filter pred (cdr list)))))
+
+  (define (partition pred list)
+    (values (filter pred list)
+            (filter (lambda (x) (not (pred x))) list)))
+
+  (define (remove pred list)
+    (filter (lambda (x) (not (pred x))) list))
+
+  (export filter partition remove)
 
   ;; # Searching
   ;; member memq memv
@@ -48,6 +99,20 @@
   ;; list-index
   ;; take-while drop-while take-while!
   ;; span break span! break!
+  (define (find-tail pred list)
+    (if (null? list)
+        #f
+        (if (pred (car list))
+            list
+            (find-tail pred (cdr list)))))
+
+  (define (find pred list)
+    (let ((tail (find-tail pred list)))
+      (if tail
+          (car tail)
+          #f)))
+
+  (export member memq memv find-tail find)
 
   ;; # Deleting
   ;; delete delete-duplicates
@@ -57,6 +122,7 @@
   ;; assoc assq assv
   ;; alist-cons alist-copy
   ;; alist-delete alist-delete!
+  (export assoc assq assv)
 
   ;; # Set operations on lists
   ;; lset<= lset= lset-adjoin
@@ -68,4 +134,4 @@
 
   ;; # Primitive side-effects
   ;; set-car! set-cdr!
-  )
+  (export set-car! set-cdr!))