Warn of Symbolic Refs at "Compile" Time?

[Nathan.Neff]

Hello,

Is there a way to be warned of symbolic references when I run
"perl -c"?

Example:-----------------------------
#!/usr/bin/perl
# This code dies when it comes to print $$var_name.
# perl -c doesn't say anything.
# How can I get perl to warn me before I run the script?
use strict;
my $YES = "The quick brown fox";
my $var_name = "YES";
print "$$var_name";

#Thanks
#--Nate

 

[xhoster]

Hello,

Is there a way to be warned of symbolic references when I run
"perl -c"?

Example:-----------------------------
#!/usr/bin/perl
# This code dies when it comes to print $$var_name.
# perl -c doesn't say anything.
# How can I get perl to warn me before I run the script?
use strict;
my $YES = "The quick brown fox";
my $var_name = "YES";
print "$$var_name";

No. At the time the last line (with the derefernce) is compiled, the
compiler doesn't know that $var_name is not going to contain a scalar
reference.

Xho

 

[Fabian Pilkowski]

Is there a way to be warned of symbolic references when I run
"perl -c"?

AFAIK, no. Calling "perl -c" checks the syntax of your script and
there's no problem within. Your script *compiles* correctly.

Example:-----------------------------
#!/usr/bin/perl
# This code dies when it comes to print $$var_name.
# perl -c doesn't say anything.
# How can I get perl to warn me before I run the script?
use strict;
my $YES = "The quick brown fox";
my $var_name = "YES";
print "$$var_name";

When printing $$var_name you get a *runtime* error. I would be surprised
if there is a possibility to detect runtime errors during compile time.

regards,
fabian

 

[Charles DeRykus]

Hello,

Is there a way to be warned of symbolic references when I run
"perl -c"?

Example:-----------------------------
#!/usr/bin/perl
# This code dies when it comes to print $$var_name.
# perl -c doesn't say anything.
# How can I get perl to warn me before I run the script?
use strict;
my $YES = "The quick brown fox";
my $var_name = "YES";
print "$$var_name";

-c will execute BEGIN and CHECK blocks so here's
something that will work in your specific case:

perl -ce 'BEGIN{ require "myscript.pl";}'
Can't use string ("YES") as a SCALAR ref while "strict refs"
in use at myscript.pl at line 8.
Compilation failed in require at -e line 1.
BEGIN failed--compilation aborted at -e line 1.

hth,

 

[Tad McClellan]

#!/usr/bin/perl

use strict;
my $YES = "The quick brown fox"; ^^
my $var_name = "YES";
print "$$var_name";

This with not output

The quick brown fox

even if you remove use strict.

Symbolic references only work for variables that are in the
symbol table, your $YES variable is not in the symbol table
(lexical variables never are).