digitalmars.D - I just have to say that string mixins rock
- Jonathan M Davis <jmdavisProg gmx.com> Jul 25 2012
- Denis Shelomovskij <verylonglogin.reg gmail.com> Jul 26 2012
- Brad Anderson <eco gnuk.net> Jul 26 2012
They've made my life way easier on a number of projects lately - particularly
involving parsing. For instance, I've got some code for parsing H.264 headers
that looks like this
mixin(parseUEV!("chroma_format_idc"));
if(chroma_format_idc == 3)
{
mixin(parseU!("separate_colour_plane_flag", 1));
}
mixin(parseUEV!("bit_depth_luma_minus8"));
mixin(parseUEV!("bit_depth_chroma_minus8"));
mixin(parseU!("qpprime_y_zero_transform_bypass_flag", 1));
mixin(parseU!("seq_scaling_matrix_present_flag", 1));
I can simply pass a variable name as a string to a template (along with the
number of bits to parse if relevant), and it'll generate a string that once
mixed in will declare that variable, parse out bits from a buffer (with a name
that the template knows) using whatever algorithm or function is associated
with that template, and assign the result to that variable. And of course that
variable is usable throughout the rest of the scope that the mixin was used
in. On top of that, all I have to do is alter the few templates that I use to
generate the strings, and I can make it print out the value, or append it to
another buffer, or assign it to a corresponding field in a struct, so on and so
forth. It saves quite a bit of code duplication, and makes it _really_ easy to
change what a whole ton of lines of code do. And the code is just as efficient
had I typed it all out myself, since it's just copy-pasted in place. This is
fantastic!
I've got a variety of such mixins in a variety of projects, and they really
help simplify the code. This is one feature in D that's really made my life
easier. So, a huge thanks to whoever though it up (probably Walter, but I
really don't know)!
- Jonathan M Davis
Jul 25 2012
Denis Shelomovskij <verylonglogin.reg gmail.com> That's why current `std.algorithm` string lambdas looks good and by design. I'm happy pull 707 is reverted. -- Денис В. Шеломовский Denis V. Shelomovskij
Jul 26 2012
--047d7b66f2cfb8e0f004c5bea206 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: quoted-printable On Thu, Jul 26, 2012 at 4:25 AM, Denis Shelomovskij < verylonglogin.reg gmail.com> wrote:That's why current `std.algorithm` string lambdas looks good and by design. I'm happy pull 707 is reverted. -- =E4=C5=CE=C9=D3 =F7. =FB=C5=CC=CF=CD=CF=D7=D3=CB=C9=CA Denis V. Shelomovskij
I do like the brevity of the string lambdas but when I first started using D I was pretty confused by them. I'm torn. In any case, I probably won't be reopening the pull request until whatever bug in DMD that was causing the test failure is fixed and who knows when that will be. Regards, Brad Anderson --047d7b66f2cfb8e0f004c5bea206 Content-Type: text/html; charset=KOI8-R Content-Transfer-Encoding: quoted-printable On Thu, Jul 26, 2012 at 4:25 AM, Denis Shelomovskij <span dir=3D"ltr"><<= a href=3D"mailto:verylonglogin.reg gmail.com" target=3D"_blank">verylonglog= in.reg gmail.com</a>></span> wrote:<br><div class=3D"gmail_quote"><block= quote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc= solid;padding-left:1ex"> That's why current `std.algorithm` string lambdas looks good and by des= ign. I'm happy pull 707 is reverted.<span class=3D"HOEnZb"><font color= =3D"#888888"><br> <br> <br> -- <br> =E4=C5=CE=C9=D3 =F7. =FB=C5=CC=CF=CD=CF=D7=D3=CB=C9=CA<br> Denis V. Shelomovskij<br> </font></span></blockquote></div><br><div>I do like the brevity of the stri= ng lambdas but when I first started using D I was pretty confused by them. = I'm torn. =9AIn any case, I probably won't be reopening the pull re= quest until whatever bug in DMD that was causing the test failure is fixed = and who knows when that will be.</div> <div><br></div><div>Regards,</div><div>Brad Anderson</div> --047d7b66f2cfb8e0f004c5bea206--
Jul 26 2012