seow
asked on
passing parameters
i've got a subrountine XYZ (in my library file) which takes in 2 parameters and then call another subroutine (not in the library file, in another file) accordingly.
eg. &XYZ("para1", "para2");
sub XYZ
{
($para1, $para2) = @_;
if (like this.....)
{
&$para1; qn=> i know the code looks stupid, but how do i call the subroutine???
}
else { &$para2; }
eg. &XYZ("para1", "para2");
sub XYZ
{
($para1, $para2) = @_;
if (like this.....)
{
&$para1; qn=> i know the code looks stupid, but how do i call the subroutine???
}
else { &$para2; }
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ozo
Passing the name of the functions as seow is doing should work too.
Yeap, it should work (and I even handed off code to show how to do it). On the other hand, I don't use labels and goto's in my perl code, even though it should work. I don't use the map function, because I'm not a lisp programmer.
M \y point was that it was stylistically preferable, and much more maintainable, to use references.
M \y point was that it was stylistically preferable, and much more maintainable, to use references.
I think ozo's point may have been that no eval or explicit reference is required, that the seow's original code actually works as is.
That is, that something like
$para1 = "para1";
&$para1;
works, calling sub para1.
That is, that something like
$para1 = "para1";
&$para1;
works, calling sub para1.
Ummm, yeah, as long as you don't have use strict .
On the other hand, I thinnk whan my answer really shows is that I hand't had enough coffee. Talk about bitchy... Some people's kids!
On the other hand, I thinnk whan my answer really shows is that I hand't had enough coffee. Talk about bitchy... Some people's kids!
I prefer references stylisticly too.
I'd probably even prototype XYZ as taking code referneces,
call it withthout the &, and declare my($para1, $para2)
(I'd also indent differently, but that's more a matter of personal taste)
I'd probably even prototype XYZ as taking code referneces,
call it withthout the &, and declare my($para1, $para2)
(I'd also indent differently, but that's more a matter of personal taste)
ASKER
thanx to all for the help.. now then i realize that my code really works.. (don know why it doesn't work b4) .. anyway.. just a few qns..
ozo: u mean i can just call my subroutine without the "&" ?? i don quite understand your last comment. Can pls elaborate more..
b2pi : thanx for your suggestions to use reference. i never thought of that and never even tried it b4.. (me still a novice) . Need to clarify something :
on your suggested answer (the 1st one) , i don understand the point 2 part.
u mean if i use reference, i must call my subroutine like &$para1() , with the brackets ?? can leave out the brackets..? does it matters that my "para1" is a subroutine ?
ozo: u mean i can just call my subroutine without the "&" ?? i don quite understand your last comment. Can pls elaborate more..
b2pi : thanx for your suggestions to use reference. i never thought of that and never even tried it b4.. (me still a novice) . Need to clarify something :
on your suggested answer (the 1st one) , i don understand the point 2 part.
u mean if i use reference, i must call my subroutine like &$para1() , with the brackets ?? can leave out the brackets..? does it matters that my "para1" is a subroutine ?
prototypes only work when you call a subroutine without using &
(which means it doesn't work calling a reference, whether strict or symbolic)
you can leave out the parentheses, see
perldoc perlsub
Try it a few different ways. We'll try to clarify anything confusing.
(which means it doesn't work calling a reference, whether strict or symbolic)
you can leave out the parentheses, see
perldoc perlsub
Try it a few different ways. We'll try to clarify anything confusing.
If you pass references to routines, they you do have to call them as &$para.
You can also call them as &{$para}
You don't need the parentheses, nor do you need to identify the package they came from. In fact, you can do them anonymously....
&XYZ(sub {
print "This is the first sub\n";
},
sub {
print "This is the second sub\n"
});
sub XYZ {
($sub1, $sub2) = @_;
if (like this.....) {
&$sub1(parm1, parm2, parm3);
} else {
&$sub2(parm1, parm2, parm3);
}
}
Some object to anonymous sub's... some object to lambda's...
[hint: I'm not one of them.. .ignore the remark about lambda's, it's really close to flamebait! :))]
You can also call them as &{$para}
You don't need the parentheses, nor do you need to identify the package they came from. In fact, you can do them anonymously....
&XYZ(sub {
print "This is the first sub\n";
},
sub {
print "This is the second sub\n"
});
sub XYZ {
($sub1, $sub2) = @_;
if (like this.....) {
&$sub1(parm1, parm2, parm3);
} else {
&$sub2(parm1, parm2, parm3);
}
}
Some object to anonymous sub's... some object to lambda's...
[hint: I'm not one of them.. .ignore the remark about lambda's, it's really close to flamebait! :))]