Author: Juergen Boemmels <[email protected]>
Branch:
Changeset: r19:e51d0791d96d
Date: 2011-11-27 22:49 +0100
http://bitbucket.org/pypy/lang-scheme/changeset/e51d0791d96d/
Log: Implement map & reverse
diff --git a/scheme/procedure.py b/scheme/procedure.py
--- a/scheme/procedure.py
+++ b/scheme/procedure.py
@@ -207,6 +207,61 @@
return w_promise.force(ctx)
+class Reverse(W_Procedure):
+ _symbol_name = "reverse"
+
+ def procedure(self, ctx, lst):
+ if len(lst) != 1:
+ raise WrongArgsNumber
+ w_inlist = lst[0]
+ w_outlist = w_nil
+ while w_inlist is not w_nil:
+ if not isinstance(w_inlist, W_Pair):
+ raise WrongArgType(lst[0], "List")
+ w_outlist = W_Pair(w_inlist.car, w_outlist)
+ w_inlist = w_inlist.cdr
+
+ return w_outlist
+
+class Map(W_Procedure):
+ _symbol_name = "map"
+
+ def procedure_tr(self, ctx, lst):
+ if len(lst) < 2:
+ raise WrongArgsNumber
+
+ w_proc = lst[0]
+ if not isinstance(w_proc, W_Procedure):
+ raise WrongArgType(w_proc, "Procedure")
+
+ args_pending = lst[1:]
+ args_len = len(args_pending)
+ args_current = [None] * args_len
+ w_rev_result = w_nil
+ finished = False
+ while True:
+ for i in range(args_len):
+ w_item = args_pending[i]
+ if w_item is w_nil:
+ finished = True
+ break
+ elif not isinstance(w_item, W_Pair):
+ raise WrongArgType(lst[i+1], "List")
+ args_current[i]= w_item.car
+ args_pending[i]= w_item.cdr
+
+ if finished:
+ break
+
+ (w_call_res, iter_ctx) = w_proc.procedure_tr(ctx, args_current)
+ while iter_ctx is not None:
+ (w_call_res, iter_ctx) = w_call_res.eval_tr(iter_ctx)
+
+ w_rev_result = W_Pair(w_call_res, w_rev_result)
+
+ # XXX need to find out how to do this tailrecusive
+ return (Reverse().procedure(ctx,[w_rev_result]), None)
+
##
# Equivalnece Predicates
##
diff --git a/scheme/test/test_scheme_level.py b/scheme/test/test_scheme_level.py
--- a/scheme/test/test_scheme_level.py
+++ b/scheme/test/test_scheme_level.py
@@ -53,10 +53,6 @@
)
(assert (eqv? (fac 1) 1))
(assert (eqv? (fac 5) 120))
-""")
-
-def test_fac_with_acc():
- run_with_assert(r"""
(define (fac n)
(define (fac-acc n acc)
(if (eqv? n 0)
@@ -69,3 +65,23 @@
(assert (eqv? (fac 1) 1))
(assert (eqv? (fac 5) 120))
""")
+
+def test_map():
+ run_with_assert(r"""
+(assert (equal?
+ (map + '(1 2 3) '(4 5 6))
+ '(5 7 9)
+))
+(assert (equal?
+ (map (lambda (n) (+ n 1)) '(1 2 3 4))
+ '(2 3 4 5)
+))
+(assert (equal?
+ (map * '(1 2 3 4 5) '(1 2 3))
+ '(1 4 9)
+))
+(assert (eq?
+ (map (lambda (n) (assert #f "should not be reached")) '())
+ '()
+))
+""")
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