Transformation from prefixed record to record

[rosemadder]

How to convert the prefix (Policy Note) into an infixed record. The record can contain: '(', ')', '+', '-', '*', '', '0..9', 'a..z'. What data structures should be used?

[baileigh]

An obvious honest algorithm is to dissolve the Polish record in a tree. Having a tree, it's possible to build any form of recording (and to optimize, compil and perform anything).

For the record.

− 5 * 6 7

You are taking the following steps:

1. You see the minus, you're setting up a binary site with two Operandas.
2. Read the first Operand.
   • See? 5, that's the first Operand, you're putting in an allotment for him.
3. Read the second Operand.
   • See? *, you're doing a binary surgery for him with twoandas.
   • Read the first Operand.
     • See? 6♪ Allocate a leaf knot with a constant ♪
     • See? 7♪ Allocate a leaf knot with a constant ♪

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For a specific purpose, the result can be simplified and not the tree built, but the data must be released immediately. Algorithm will be like this:

• Read one token.
• If it's a constant, it's a result.
• If it's a binary operation, remembrance her type, get the meaning of the operars, put it in brackets to avoid thinking about the priority of operators.
• supplement the rules for other types of nodes