Am Sun, 15 May 2011 13:26:03 +0200 (CEST)
schrieb Daniël Mantione <daniel.manti...@freepascal.org>:
> Feel free to come up with examples and convince us. They need to be
> examples of code that is much more awkward to write without macro's.
We extend the small enumeration example:
Think of it, as a server program with a lot of callback procedures and
associated data
procedure cb_proc1();begin ... end;
procedure cb_proc2();begin ... end;
procedure cb_proc3();begin ... end;
procedure cb_proc4();begin ... end;
procedure cb_proc5();begin ... end;
procedure cb_proc6();begin ... end;
type
callenum=(
proc1,
proc2,
proc3,
proc4,
proc5,
proc6
);
callproc=procedure();
inforec=record
id:callenum;name:string[12];address:callproc
end;
const
infoarr:array[callenum] of inforec={
{id:proc1;name:'proc1';address:@cb_proc1},
{id:proc2;name:'proc2';address:@cb_proc2},
{id:proc3;name:'proc3';address:@cb_proc3},
{id:proc4;name:'proc4';address:@cb_proc4},
{id:proc5;name:'proc5';address:@cb_proc5},
{id:proc6;name:'proc6';address:@cb_proc6}
}
What I possibly would do is:
{$Makro entry(n):={id:proc %% %n%; // concat with parameter
name:'proc' %% % %n%; // concat with str par
address:@cb_proc %% %n% // concat with parameter
}
}
used with the explicit syntax:
infoarr:array[1..6] of inforec={
{$Expand entry(1)},
{$Expand entry(2)},
{$Expand entry(3)},
{$Expand entry(4)},
{$Expand entry(5)},
{$Expand entry(6)},
}
thats nice enough if you have 57 elements in your callenum. Would you
say then, use an IDE instead of? Every time I change the inforec, which
is possibly not that seldom, I only change the macro once. Is this not
nice? Macros simply can help to keep the things together.
Again:
The point is not, to find an example, which is not doable without
macros.
The point is, to show that the concept of automated text changing is
useful.
Regards
Jörg
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