text/flat: FlatText::char_to_byte_index shortcut length_of_char_at if possible

[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 ffd0999..62f3b5e 100644 (file)
--- a/lib/core/text/string_search.nit
+++ b/lib/core/text/string_search.nit
@@ -277,6 +277,22 @@ class Match
        # ~~~
        redef fun to_s do return string.substring(from,length)
 
+       # The content of `string` before the match
+       #
+       # ~~~
+       # var m = "hello world".search("lo")
+       # assert m.text_before == "hel"
+       # ~~~
+       fun text_before: String do return string.substring(0, from)
+
+       # The content of `string` after the match
+       #
+       # ~~~
+       # var m = "hello world".search("lo")
+       # assert m.text_after == " world"
+       # ~~~
+       fun text_after: String do return string.substring_from(after)
+
        init
        do
                assert positive_length: length >= 0
@@ -383,6 +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]