Function Parse

syntax/parse.go:35–62

Parse syntax parsing. Program -> IntDeclaration | ExpressionStatement | AssignmentStatement IntDeclaration -> 'int' Id ( = Additive) '\n' ExpressionStatement -> Additive '\n' Additive -> Multiplicative ( (+ | -) Multiplicative)* Multiplicative -> Primary ((* | /) Primary)* Primary -> IntLiteral | Id

(script string)

// Primary -> IntLiteral | Id | Additive
// AssignmentStatement -> Identifier = Additive
func Parse(script string) (*ASTNode, error) {
	tokenTypes := token.Tokenize(script)
	reader := NewTokenReader(tokenTypes)

	root := NewASTNode(Program, App)
	var err error
	for reader.Peek() != nil {
		child, _ := IntDeclare(reader)

		if child == nil {
			child, err = ExpressionStatement(reader)
		}

		if child == nil {
			child, err = AssignmentStatement(reader)
		}

		if child != nil {
			root.AddChild(child)
		} else {
			return nil, errors.New("syntax err: Invalid statement")
		}
	}

	//cal.PrintASTNode(root, "")

	return root, err
}

// ExpressionStatement -> 1+2*3 '\n'
func ExpressionStatement(reader *TokenReader) (*ASTNode, error) {