Add goroutines

ast.go

@@ -268,6 +268,12 @@ func executeCmd(cmd *Command) error {
 				return fmt.Errorf("%s: %s", Call.Pos, err)
 			}
 		}
+	} else if cmd.Goroutines != nil {
+		// For each function call
+		for _, goroutine := range cmd.Goroutines {
+			// Attempt to call function
+			go CallFunction(goroutine.Call)
+		}
 	} else if cmd.Ifs != nil {
 		// For each if statement
 		for _, If := range cmd.Ifs {
@@ -316,7 +322,8 @@ type Command struct {
 	RptLoops   []*RptLoop   `| @@`
 	WhlLoops   []*WhlLoop   `| @@`
 	Defs       []*FuncDef   `| @@`
-	Calls    []*FuncCall `| @@)`
+	Goroutines []*Goroutine `| @@`
+	Calls      []*FuncCall  `| @@ )`
 }
 
 // Value stores any literal values encountered while parsing a script
@@ -352,6 +359,11 @@ type FuncCall struct {
 	Args []*Arg `@@*`
 }
 
+type Goroutine struct {
+	Pos  lexer.Position
+	Call *FuncCall `"go" @@`
+}
+
 // Arg stores arguments for function calls
 type Arg struct {
 	Pos   lexer.Position