From 61aaa4f0dea74351644ef91e4ffaa02e9c4a9d51 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Mon, 3 Dec 2007 23:54:59 -0600
Subject: [PATCH] Add nfirst to combinators.lib and add seq>stack

---
 extra/combinators/lib/lib-tests.factor | 2 ++
 extra/combinators/lib/lib.factor       | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/extra/combinators/lib/lib-tests.factor b/extra/combinators/lib/lib-tests.factor
index 43385b911d..0d76e6f50d 100644
--- a/extra/combinators/lib/lib-tests.factor
+++ b/extra/combinators/lib/lib-tests.factor
@@ -58,3 +58,5 @@ IN: temporary
         [ dup array? ] [ dup vector? ] [ dup float? ]
     } || nip
 ] unit-test
+
+[ 1 2 3 4 ] [ { 1 2 3 4 } 4 nfirst ] unit-test
diff --git a/extra/combinators/lib/lib.factor b/extra/combinators/lib/lib.factor
index 3f49da7cb3..fe11fd1338 100644
--- a/extra/combinators/lib/lib.factor
+++ b/extra/combinators/lib/lib.factor
@@ -67,6 +67,12 @@ MACRO: napply ( n -- )
 
 : map-with2 ( obj obj list quot -- newseq ) 2 map-withn ; inline
 
+MACRO: nfirst ( n -- )
+    [ [ swap nth ] curry [ keep ] curry ] map concat [ drop ] compose ;
+
+: seq>stack ( seq -- )
+    dup length nfirst ; inline
+
 ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
 : sigma ( seq quot -- n ) [ rot slip + ] curry 0 swap reduce ;