从前缀顺序表达式构建语法树的算法

Question

什么类型的算法将用于从以前缀顺序表示法表示的表达式构造语法树？

Answer 1

一个简单的递归算法可以将前缀顺序表达式转换为语法树。

GetNextPrefixExpression(tokenStream)
    nextToken = tokenStream.GetNextToken()
    if nextToken.IsValue()
        return new Value(nextToken)
    else if nextToken.IsUnaryOperator()
        return new UnaryOperator(nextToken, GetNextPrefixExpression(tokenStream))
    else if nextToken.IsBinaryOperator()
        return new BinaryOperator(nextToken, GetNextPrefixExpression(tokenStream), GetNextPrefixExpression(tokenStream))
    else if nextToken.IsTrinaryOperator()
        return new TrinaryOperator(nextToken, GetNextPrefixExpression(tokenStream), GetNextPrefixExpression(tokenStream), GetNextPrefixExpression(tokenStream))