sequences: adding find-index-from.

[factor.git] / core / sequences / sequences.factor

diff --git a/core/sequences/sequences.factor b/core/sequences/sequences.factor
index 79847b0abf98604bf89f34eb53d125950ef1c220..0f208e2cabdcf882ae342b8c43b509063041eb32 100644 (file)
--- a/core/sequences/sequences.factor
+++ b/core/sequences/sequences.factor
@@ -420,6 +420,12 @@ PRIVATE>
 : (find-index) ( seq quot quot' -- i elt )
     pick [ [ (each-index) ] dip call ] dip finish-find ; inline
 
+: (find-index-from) ( n seq quot quot' -- i elt )
+    [ 2dup bounds-check? ] 2dip
+    [ (find-index) ] 2curry
+    [ 2drop f f ]
+    if ; inline
+
 : (accumulate) ( seq identity quot -- identity seq quot )
     swapd [ curry keep ] curry ; inline
 
@@ -494,6 +500,9 @@ PRIVATE>
 : find-last ( ... seq quot: ( ... elt -- ... ? ) -- ... i elt )
     [ [ 1 - ] dip find-last-integer ] (find) ; inline
 
+: find-index-from ( ... n seq quot: ( ... elt i -- ... ? ) -- ... i elt )
+    [ (find-integer) ] (find-index-from) ; inline
+
 : find-index ( ... seq quot: ( ... elt i -- ... ? ) -- ... i elt )
     [ find-integer ] (find-index) ; inline