Method parseBinOpRHS

engine/ast.go:237–267

(execPrec int, lhs ExprAST)

}

func (a *AST) parseBinOpRHS(execPrec int, lhs ExprAST) ExprAST {
	for {
		tokPrec := a.getTokPrecedence()
		if tokPrec < execPrec {
			return lhs
		}
		binOp := a.currTok.Tok
		if a.getNextToken() == nil {
			a.Err = errors.New(
				fmt.Sprintf("want '(' or '0-9' but get EOF\n%s",
					ErrPos(a.source, a.currTok.Offset)))
			return nil
		}
		rhs := a.parsePrimary()
		if rhs == nil {
			return nil
		}
		nextPrec := a.getTokPrecedence()
		if tokPrec < nextPrec {
			rhs = a.parseBinOpRHS(tokPrec+1, rhs)
			if rhs == nil {
				return nil
			}
		}
		lhs = BinaryExprAST{
			Op:  binOp,
			Lhs: lhs,
			Rhs: rhs,
		}
	}
}