lib: Perfized `to_hex` and have it work anywhere in a `Text`

[nit.git] / lib / core / text / string_search.nit

diff --git a/lib/core/text/string_search.nit b/lib/core/text/string_search.nit
index b143e71..62f3b5e 100644 (file)
--- a/lib/core/text/string_search.nit
+++ b/lib/core/text/string_search.nit
@@ -399,6 +399,37 @@ redef class Text
                return null
        end
 
+       # Extract a given prefix, if any.
+       #
+       # ~~~
+       # var p = "hello world".prefix("hello")
+       # assert p != null
+       # assert p.text_after == " world"
+       # ~~~
+       fun prefix(t: Text): nullable Match do
+               var len = t.length
+               if substring(0, len) == t then
+                       return new Match(self.to_s, 0, len)
+               end
+               return null
+       end
+
+       # Extract a given suffix, if any.
+       #
+       # ~~~
+       # var p = "hello world".suffix("world")
+       # assert p != null
+       # assert p.text_before == "hello "
+       # ~~~
+       fun suffix(t: Text): nullable Match do
+               var len = t.length
+               var from = length - len
+               if substring(from, len) == t then
+                       return new Match(self.to_s, from, len)
+               end
+               return null
+       end
+
        # Search all occurrences of `pattern` into self.
        #
        #     var a = new Array[Int]