Function parseFuncDef

parser/functype.go:18–113

(b []byte)

}

func parseFuncDef(b []byte) (*funcType, error) {
	defStr := string(b)

	// extract func name
	n := strings.Index(defStr, "(")
	if n < 0 {
		return nil, fmt.Errorf("cannot find '(' in function definition")
	}
	name := defStr[:n]
	defStr = defStr[n+1:]
	defPrefix := ""
	callPrefix := ""
	if len(name) == 0 {
		// Either empty func name or valid method definition. Let's check.

		// parse method receiver
		n = strings.Index(defStr, ")")
		if n < 0 {
			return nil, fmt.Errorf("cannot find ')' in func")
		}
		recvStr := defStr[:n]
		defStr = defStr[n+1:]
		exprStr := fmt.Sprintf("func (%s)", recvStr)
		expr, err := goparser.ParseExpr(exprStr)
		if err != nil {
			return nil, fmt.Errorf("invalid method definition: %s", err)
		}
		ft := expr.(*ast.FuncType)
		if len(ft.Params.List) != 1 || len(ft.Params.List[0].Names) != 1 {
			// method receiver must contain only one param
			return nil, fmt.Errorf("missing func or method name")
		}
		recvName := ft.Params.List[0].Names[0].Name
		defPrefix = fmt.Sprintf("(%s) ", recvStr)
		callPrefix = recvName + "."

		// extract method name
		n = strings.Index(defStr, "(")
		if n < 0 {
			return nil, fmt.Errorf("missing func name")
		}
		name = string(stripLeadingSpace([]byte(defStr[:n])))
		if len(name) == 0 {
			return nil, fmt.Errorf("missing method name")
		}
		defStr = defStr[n+1:]
	}

	// validate and collect func args
	if len(defStr) == 0 || defStr[len(defStr)-1] != ')' {
		return nil, fmt.Errorf("missing ')' at the end of func")
	}
	args := defStr[:len(defStr)-1]
	exprStr := fmt.Sprintf("func (%s)", args)
	expr, err := goparser.ParseExpr(exprStr)
	if err != nil {
		return nil, fmt.Errorf("invalid func args: %s", err)
	}