Solve math question in PHP

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Published on 2010-05-15T18:42:43Z Indexed on 2010/05/15 18:44 UTC
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Filed under:

php

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math

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parsing

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user-input

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problem-solving

The user can enter a math problem like 5 + 654, 6 ^ 24, 2!, sqrt(543), log(54), sin 5, sin(50). After some reformatting (e.g. change sin 5 into sin(5)), and doing an eval, PHP gives me the right result. However, this is quite unsafe. Can anyone point me in the right direction parsing and solving a math question like the examples above, which is safe? Thanks.

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