feat(goctl): Add api parser (#2585)

tools/goctl/pkg/parser/api/token/position.go

@@ -0,0 +1,21 @@
+package token
+
+import "fmt"
+
+// IllegalPosition is a position that is not valid.
+var IllegalPosition = Position{}
+
+// Position represents a rune position in the source code.
+type Position struct {
+	Filename string
+	Line     int
+	Column   int
+}
+
+// String returns a string representation of the position.
+func (p Position) String() string {
+	if len(p.Filename) == 0 {
+		return fmt.Sprint(p.Line, ":", p.Column)
+	}
+	return fmt.Sprint(p.Filename, " ", p.Line, ":", p.Column)
+}