parse Expression
Parses an arithmetic expression from the given string.
Any unknown alphanumeric token that is not a number or an element is considered as a variable.
Return
the parsed KthExpression
Parameters
expr
the arithmetic expression to parse
See also
Parses an arithmetic expression from the receiving string.
Any unknown alphanumeric token that is not a number or an element is considered as a variable.
Return
the parsed KthExpression