Added textutils.ExtractRange function

Author: cmaglie

handler/textutils/textutils.go

@@ -23,23 +23,23 @@ func ApplyLSPTextDocumentContentChangeEvent(textDoc *lsp.TextDocumentItem, chang
 
 // ApplyTextChange replaces startingText substring specified by replaceRange with insertText
 func ApplyTextChange(startingText string, replaceRange lsp.Range, insertText string) (res string, err error) {
-	start, err := getOffset(startingText, replaceRange.Start)
+	start, err := GetOffset(startingText, replaceRange.Start)
 	if err != nil {
 		return "", err
 	}
-	end, err := getOffset(startingText, replaceRange.End)
+	end, err := GetOffset(startingText, replaceRange.End)
 	if err != nil {
 		return "", err
 	}
 
 	return startingText[:start] + insertText + startingText[end:], nil
 }
 
-// getOffset computes the offset in the text expressed by the lsp.Position.
+// GetOffset computes the offset in the text expressed by the lsp.Position.
 // Returns OutOfRangeError if the position is out of range.
-func getOffset(text string, pos lsp.Position) (int, error) {
+func GetOffset(text string, pos lsp.Position) (int, error) {
 	// Find line
-	lineOffset, err := getLineOffset(text, pos.Line)
+	lineOffset, err := GetLineOffset(text, pos.Line)
 	if err != nil {
 		return -1, err
 	}
@@ -74,13 +74,13 @@ func getOffset(text string, pos lsp.Position) (int, error) {
 	return -1, OutOfRangeError{"Character", count, character}
 }
 
-// getLineOffset finds the offset/position of the beginning of a line within the text.
+// GetLineOffset finds the offset/position of the beginning of a line within the text.
 // For example:
 //    text := "foo\nfoobar\nbaz"
-//    getLineOffset(text, 0) == 0
-//    getLineOffset(text, 1) == 4
-//    getLineOffset(text, 2) == 11
-func getLineOffset(text string, line int) (int, error) {
+//    GetLineOffset(text, 0) == 0
+//    GetLineOffset(text, 1) == 4
+//    GetLineOffset(text, 2) == 11
+func GetLineOffset(text string, line int) (int, error) {
 	if line == 0 {
 		return 0, nil
 	}
@@ -100,6 +100,19 @@ func getLineOffset(text string, line int) (int, error) {
 	return -1, OutOfRangeError{"Line", count, line}
 }
 
+// ExtractRange extract a piece of text from a text document given the range
+func ExtractRange(text string, textRange lsp.Range) (string, error) {
+	start, err := GetOffset(text, textRange.Start)
+	if err != nil {
+		return "", err
+	}
+	end, err := GetOffset(text, textRange.End)
+	if err != nil {
+		return "", err
+	}
+	return text[start:end], nil
+}
+
 // OutOfRangeError returned if one attempts to access text out of its range
 type OutOfRangeError struct {
 	Type string

handler/textutils/textutils_test.go

@@ -128,7 +128,7 @@ func TestGetOffset(t *testing.T) {
 		st := strings.Replace(test.Text, "\n", "\\n", -1)
 
 		t.Logf("getOffset(\"%s\", {Line: %d, Character: %d}) == %d", st, test.Line, test.Char, test.Exp)
-		act, err := getOffset(test.Text, lsp.Position{Line: test.Line, Character: test.Char})
+		act, err := GetOffset(test.Text, lsp.Position{Line: test.Line, Character: test.Char})
 		if act != test.Exp {
 			t.Errorf("getOffset(\"%s\", {Line: %d, Character: %d}) != %d, got %d instead", st, test.Line, test.Char, test.Exp, act)
 		}
@@ -158,7 +158,7 @@ func TestGetLineOffset(t *testing.T) {
 		st := strings.Replace(test.Text, "\n", "\\n", -1)
 
 		t.Logf("getLineOffset(\"%s\", %d) == %d", st, test.Line, test.Exp)
-		act, err := getLineOffset(test.Text, test.Line)
+		act, err := GetLineOffset(test.Text, test.Line)
 		if act != test.Exp {
 			t.Errorf("getLineOffset(\"%s\", %d) != %d, got %d instead", st, test.Line, test.Exp, act)
 		}