Re: [Flex-help] Starter question.

[Simon S. <sim...@gn...>]

Hi and welcome to the world of lexers!

Am 27.02.2019 um 14:36 schrieb Wor...@gm...:
5. .|\n                    { printf("do nothing"); }
6. [_a-zA-Z0-9]+\(     { printf("This is a function name %s
   (steps=%i)", yytext, steps++); }

>> Now my problem is that also strings like 12342welcome( are beeing
>> "marked" as beeing functions ... what am i doing wrong here ? the
>> default route .|\n is said to do nothing, so why does he matches also
>> digits with my function catching example ?

Actually you've said that anything that consist only of *at least one*
("+") from the following set "[_a-zA-Z0-9]" (directly followed by a "(")
is a function.
As you did not specify what you want to do you may want to mark only
functions if they not start with a number, using a fixed and an optional
set (* matches zero to unlimited occurrences):

[_a-zA-Z]+[_a-zA-Z0-9]*\(

you may also want to add optional spaces before "\(".

> I've replaced the lines 5 and 6 because he matches first the lines
> with the most matches and that is normaly .|\n but again same problem
> =(.

If I'm not wrong the *longest* match is the preferred one and as this
rule matches only a single character it should normally not be used.

Simon