experimental HiFi tree diff algorithm for use with quick-fixes and refactoring commands in the IDE

src/org/rascalmpl/library/Prelude.java

@@ -3047,6 +3047,10 @@
 
 		return values.string(chars);
 	}
+
+	public IString indent(IString indentation, IString content, IBool indentFirstLine) {
+		return content.indent(indentation, indentFirstLine.getValue());
+	}
 
 	public IValue charAt(IString s, IInteger i) throws IndexOutOfBoundsException
 	//@doc{charAt -- return the character at position i in string s.}

src/org/rascalmpl/library/String.rsc

@@ -627,3 +627,19 @@ str substitute(str src, map[loc,str] s) {
     order = sort([ k | k <- s ], bool(loc a, loc b) { return a.offset < b.offset; });
     return ( src | subst1(it, x, s[x]) | x <- order );
 }
+
+@synopsis{Indent a block of text}
+@description{
+Every line in `content` will be indented using the characters
+of `indentation`.
+}
+@benefits{
+* This operation executes in constant time, independent of the size of the content
+or the indentation.
+* Indent is the identity function if `indentation == ""`
+}
+@pitfalls{
+* This function works fine if `indentation` is not spaces or tabs; but it does not make much sense. 
+}
+@javaClass{org.rascalmpl.library.Prelude}
+java str indent(str indentation, str content, bool indentFirstLine=false);

src/org/rascalmpl/library/analysis/diff/edits/ExecuteTextEdits.rsc

@@ -24,16 +24,21 @@ void executeDocumentEdit(renamed(loc from, loc to)) {
 }
 
 void executeDocumentEdit(changed(loc file, list[TextEdit] edits)) {
+    str content = readFile(file);
+
+    content = executeTextEdits(content, edits);
+
+    writeFile(file.top, content);
+}
+
+str executeTextEdits(str content, list[TextEdit] edits) {
     assert isSorted(edits, less=bool (TextEdit e1, TextEdit e2) { 
         return e1.range.offset < e2.range.offset; 
     });
 
-    str content = readFile(file);
-
     for (replace(loc range, str repl) <- reverse(edits)) {
-        assert range.top == file.top;
         content = "<content[..range.offset]><repl><content[range.offset+range.length..]>";
     }
 
-    writeFile(file.top, content);
+    return content;
 }