Re: [ShopSuite-dev] [rational type] X/1 --> X

[Davi Leal]

Tomasz Wegrzanowski wrote:

> On Fri, Aug 31, 2001 at 11:40:11PM +0100, Davi Leal wrote:
> > I have modified rational_out() to realize the X/1 --> X conversion. The GUI 
> > is
> > more readable and clean now.
> >
> > I have tried some modifications to rational_in() but I have not finished it
> > yet. Its goal is to check the format at input so as to fit fully the below
> > regular expressions. If the input does not fit then RETURN_UNDEF is used. 
> > See
> > the attached rational.c file. Execute 'cvs diff rational.c'.
> >
> >     Number:   "^ *[0-9]\+ *$"
> >     Rational: "^ *[0-9]\+\/[0-9]\+ *$"
>
> Why did you escape '+' ?

I had to escape it at the ':' vim's prompt, which I used to check it.



> > Do you know about regcomp() and regexec(). Do you have any idea of how check
> > if the input match a regular expressions?.
>
> It's simple and I even have some helloworlds available
> (I allways write helloworlds when I'm learning something new,
> and I often save them for reference).
> Tell me if you want me to send them to you.

Please, send me it.



> But I don't know if it's any useful.
> Parser is quite simple, and finding number start and end
> is only half of parsing.

Well, ... I think the use of a regular expression checker make it easier and 
less
prone to mistake at some cases. See below:

                    "2  "  -->     "2"
                 "  23  "  -->    "23"
                 " 4/7  "  -->   "4/7"
                   "sk2 "  -->   "0/0"
                " 3/4 A"  --> "0/0"
                " 3/4 A "  --> "0/0"

                " 3/4 8"  --> "0/0"
                " 3/48  "  --> "1/16"
                Note that the initial and final blanks are
                stripped but not the middle ones.