FINALLY errors and lexer agree on row/col positions properly

errors/errors.go

@@ -24,8 +24,11 @@ func (pos Position) Format () string {
 	line   := formatTabs(pos.Line)
 	output := fmt.Sprintf("%-4d | %s\n       ", pos.Row + 1, line)
 
-	start := getXInTabbedString(pos.Line, pos.Start)
-	end   := getXInTabbedString(pos.Line, pos.End)
+	start := pos.Start
+	end   := pos.End
+	if end <= start { end = start + 1 }
+	start = getXInTabbedString(pos.Line, start)
+	end   = getXInTabbedString(pos.Line, end)
 
 	for index := range line {
 		if index >= end { break }

lexer/lexer.go

@@ -383,8 +383,8 @@ func (this *fsplLexer) pos () errors.Position {
 	return errors.Position {
 		File:   this.filename,
 		Line:   this.lineScanner.Text(),
-		Row:    this.row,
-		Start:  this.column,
+		Row:    this.row    - 1,
+		Start:  this.column - 1,
 		End:    this.column,
 	}
 }

lexer/lexer_test.go

@@ -8,7 +8,7 @@ testString(test, "", tok(EOF, ""))
 
 func TestLexerErrUnexpectedRune (test *testing.T) {
 testStringErr(test,
-"unexpected rune '\"'", `ooo " hahsdklhasldk`, 3, 5,
+"unexpected rune '\"'", `ooo " hahsdklhasldk`, 2, 4,
 `
 valid tokens valid tokens
 ooo " hahsdklhasldk
@@ -23,7 +23,7 @@ tok(0, ""),
 
 func TestLexerErrUnexpectedEOF (test *testing.T) {
 testStringErr(test,
-"unexpected EOF", `'this is a string that does not end...`, 2, 39,
+"unexpected EOF", `'this is a string that does not end...`, 1, 38,
 `
 'this is a string that does not end...`,
 tok(String, "this is a string that does not end..."),