"Evaluate mathematical expression" https://www.codewars.com//kata/52a78825cdfc2cfc87000005/javascript by Ant Kaynak
Trigger Warning! Might contain messy code.
Given a mathematical expression as a string you must return the result as a number.
Number may be both whole numbers and/or decimal numbers. The same goes for the returned result.
You need to support the following mathematical operators:
- Multiplication *
- Division / (as floating point division)
- Addition +
- Subtraction - Operators are always evaluated from left-to-right, and * and / must be evaluated before + and -.
You need to support multiple levels of nested parentheses, ex. (2 / (2 + 3.33) * 4) - -6
There may or may not be whitespace between numbers and operators.
An addition to this rule is that the minus sign (-) used for negating numbers and parentheses will never be separated by whitespace. I.e all of the following are valid expressions.
1-1 // 0
1 -1 // 0
1- 1 // 0
1 - 1 // 0
1- -1 // 2
1 - -1 // 2
6 + -(4) // 2
6 + -( -4) // 10
And the following are invalid expressions
1 - - 1 // Invalid 1- - 1 // Invalid 6 + - (4) // Invalid 6 + -(- 4) // Invalid
You do not need to worry about validation - you will only receive valid mathematical expressions following the above rules.
NOTE: Both eval and Function are disabled.