add if-zero/when-zero/unless-zero to core/ and update usages

[factor.git] / core / io / encodings / utf8 / utf8.factor

diff --git a/core/io/encodings/utf8/utf8.factor b/core/io/encodings/utf8/utf8.factor
index 4846b06f32d29023bbf2d257a24c2554d3852b61..a722655cad4a81dfcecf2e094bab0ae2a23392ad 100755 (executable)
--- a/core/io/encodings/utf8/utf8.factor
+++ b/core/io/encodings/utf8/utf8.factor
@@ -73,14 +73,14 @@ M: utf8 encode-char
 PRIVATE>
 
 : code-point-length ( n -- x )
-    dup zero? [ drop 1 ] [
+    [ 1 ] [
         log2 {
             { [ dup 0 6 between? ] [ 1 ] }
             { [ dup 7 10 between? ] [ 2 ] }
             { [ dup 11 15 between? ] [ 3 ] }
             { [ dup 16 20 between? ] [ 4 ] }
         } cond nip
-    ] if ;
+    ] if-zero ;
 
 : code-point-offsets ( string -- indices )
     0 [ code-point-length + ] accumulate swap suffix ;