diff -r f66a9d2069a1 lib/string/abstract_string.li
--- a/lib/string/abstract_string.li	Sun Aug 31 13:14:18 2008 +0200
+++ b/lib/string/abstract_string.li	Sun Aug 31 13:31:45 2008 +0200
@@ -196,7 +196,11 @@
     ? { valid_index i};
     storage.item (i - 1).code
   );
-  
+
+  - contains ch:CHARACTER :BOOLEAN <- valid_index (index_of ch);
+
+  - index_of ch:CHARACTER :INTEGER <- index_of ch since 1;
+
   - index_of ch:CHARACTER since start_index:INTEGER :INTEGER <-
   // Index of first occurrence of `c' at or after `start_index',
   // result = count + 1, if none.
@@ -212,6 +216,8 @@
     result
   );
   
+  - last_index_of ch:CHARACTER :INTEGER <- last_index_of ch since upper;
+
   - last_index_of ch:CHARACTER since start_index:INTEGER :INTEGER <-
   // Index of first occurrence of `c' at or before `start_index',
   // 0 if none.
@@ -227,7 +233,7 @@
     ? {(result != 0) ->> {item result == ch}};    
     result
   );
-  
+
   - fast_index_of ch:CHARACTER :INTEGER <-
   // Gives the index of the first occurrence `ch' or
   // 0 if none.
@@ -832,10 +838,86 @@
     
     substring_index (other,1)
   );
-  
+
+  - replace pattern:ABSTRACT_STRING by replacement:ABSTRACT_STRING :STRING <-
+  ( + result :STRING;
+    + i, j :INTEGER;
+    result := STRING.create count;
+    i := lower;
+    j := substring_index (pattern, i); // first character of the pattern
+    { j = 0 }.until do {
+      result.append (substring i to (j-1)); // TODO: optimize
+      result.append replacement;
+      i := j + pattern.count; // first character after the pattern
+      j := substring_index (pattern, i); // first character of the pattern
+    };
+    result.append (substring i to upper); // TODO: optimize
+    result
+  );
+
   //
   // Splitting a STRING:
   //
+
+  - partition sep:ABSTRACT_STRING from start_index:INTEGER :(STRING, STRING, STRING) <-
+  [
+    -? {sep != NULL};
+    -? {valid_index start_index};
+  ]
+  ( + i, j:INTEGER;
+    + head, sep, tail :STRING;
+    i := substring_index (sep, start_index);
+    (i = 0).if {
+      // Not found
+      head := to_string;
+    } else {
+      // Found
+      j := i + sep.count;
+      (i > lower).if {
+        head := substring lower to (i-1);
+      };
+      sep  := substring i to j;
+      (j < upper).if {
+        tail := substring (j+1) to upper;
+      };
+    };
+    head, sep, tail
+  );
+
+  - partition sep:ABSTRACT_STRING :(STRING, STRING, STRING) <-
+  (
+    partition sep from lower
+  );
+
+  - last_partition sep:ABSTRACT_STRING from start_index:INTEGER :(STRING, STRING, STRING) <-
+  [
+    -? {sep != NULL};
+    -? {valid_index start_index};
+  ]
+  ( + i, j:INTEGER;
+    + head, sep, tail :STRING;
+    i := last_substring_index (sep, start_index);
+    (i = 0).if {
+      // Not found
+      head := to_string;
+    } else {
+      // Found
+      j := i + sep.count;
+      (i > lower).if {
+        head := substring lower to (i-1);
+      };
+      sep  := substring i to j;
+      (j < upper).if {
+        tail := substring (j+1) to upper;
+      };
+    };
+    head, sep, tail
+  );
+
+  - last_partition sep:ABSTRACT_STRING :(STRING, STRING, STRING) <-
+  (
+    last_partition sep from upper
+  );
   
   - split:ARRAY[STRING] <-
   // Split the string into an array of words. Uses `is_separator' of
diff -r f66a9d2069a1 lib2/string/abstract_string.li
--- a/lib2/string/abstract_string.li	Sun Aug 31 13:14:18 2008 +0200
+++ b/lib2/string/abstract_string.li	Sun Aug 31 13:31:45 2008 +0200
@@ -916,6 +916,36 @@
     partition sep from lower
   );
 
+  - last_partition sep:ABSTRACT_STRING from start_index:INTEGER :(STRING, STRING, STRING) <-
+  [
+    -? {sep != NULL};
+    -? {valid_index start_index};
+  ]
+  ( + i, j:INTEGER;
+    + head, sep, tail :STRING;
+    i := last_substring_index (sep, start_index);
+    (i = 0).if {
+      // Not found
+      head := to_string;
+    } else {
+      // Found
+      j := i + sep.count;
+      (i > lower).if {
+        head := substring lower to (i-1);
+      };
+      sep  := substring i to j;
+      (j < upper).if {
+        tail := substring (j+1) to upper;
+      };
+    };
+    head, sep, tail
+  );
+
+  - last_partition sep:ABSTRACT_STRING :(STRING, STRING, STRING) <-
+  (
+    last_partition sep from upper
+  );
+
   - split_str sep:ABSTRACT_STRING :ARRAY[STRING] <-
   [
     -? {sep != NULL};