Hiya monks,
Im having trouble getting my head around a regular expression to match sequences.
I need to catch all exceptions where a mathematical expression is illegal...

there must be either a letter or a digit either side of an operator
parenthesis must open & close next to letters or digits, not next to operators, and do not have to exist
variables must not be more than one letter
Nothing other than a-z,A-Z,0-9,+,-,*,/,(,) can be used

I have got as far as this... 

!~ \([a-zA-Z]?|[0-9]*\s[\+\-\*\/]?[a-zA-Z]?|[0-9]*\)

[download]
but is still limited as it only looks at (a + 3) and not anything beyond, like (3 * 4)+(b + x) or (5 - a)*z or even a simple 3 + 2.

Can anyone offer a hand on how best to tackle this problem?

many thanks

In reply to Complex regex for maths formulas by Anonymous Monk

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