Sorry for the late reply.
On 3/9/22 12:02 AM, Johannes Sixt <j6t@xxxxxxxx> wrote:
Am 08.03.22 um 17:54 schrieb jaydeepjd.8914@xxxxxxxxx:
> So, the final regexes are these, right?:
Not quite.
>
> "[a-zA-Z_][a-zA-Z0-9_]*"
> /* hexadecimal and binary numbers */
> "|0[xXbB][0-9a-fA-F_]+[lLuU]*"
> /* integers and floats */
> "|[0-9][.]?[0-9_]+([Ee][-+]?[0-9]+)?[fFlLuU]*"
This would not match 12.5 because you allow only a single digit before
the decimal point. Perhaps
"|[0-9][.0-9_]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
Okay.
> /* floating point numbers beginning with decimal point */
> "|[.][0-9][0-9_]*([Ee][-+]?[0-9]+)?[fFlL]?"
> /* unary and binary operators */
>
> "|[-+*/<>%&^|=!]?==?|--|\\+\\+|<<=|>>=|&&|[||]|->|\\.\\*|!!|::|[?:.][.:]"),
[||] does not work as you intend. A new suggestion: do not start with an
initial optional character in order to reduce the number of
backtrackings that the regular expression evaluation has to do. I would
write this line as
"|[-+*/<>%&^|=!]==?|--|\\+\\+|<<=|>>=|&&|\\|\\||->|\\.\\*|!!|::|[?:.][.:]"),
BTW which operators are handled by "[?:.][.:]"? I'm asking because you
list :: separatly that would also be matched by this sub-expression.
It matches the following operators: `?:`, `?.`, `..` `::`. Although matching `::` is
unnecessary since its matched before.
https://kotlinlang.org/docs/keyword-reference.html#operators-and-special-symbols
