symbolic-references

If I have a variable, $bar , which is equal to string "foo" and $foo is equal to 0xdead , how can I get $foo 's value while I only have the the string for the variable name? Essentially, I want to do a kind of pointer indirection on the global namespace or a hash lookup on the global namespace. The following didn't work: perl -e 'my $foo=0xdead; my $bar ="foo"; print ${$bar}."\n";' It only prints the newline. This trick works only with global variables (symbolic references seek the symbol table of the current package), i. e. perl -e '$foo=0xdead; my $bar ="foo"; print ${$bar}."\n";' If you

Why does the following snippet work at all? And what evil might be possible using this? But seriously, is there any reason, the code in ${} gets evaluated at all and then used as scalar reference? use strict; no strict 'refs'; our $message = "Hello world!"; print "${ lc 'MESSAGE' }\n"; codeholic It's ok, unless you use symbolic references . Suppose the following code: my %messages = (hello => "Hello world!", bye => "Bye-bye, world!"); sub get_message_ref { return \$messages{$_[0]} }; # returns scalarref print "${ get_message_ref('bye') }\n"; Agree, its usefulness is not obvious with scalarrefs

The following shell code correctly creates a chain of symbolic references git symbolic-ref "first" "refs/heads/master" git symbolic-ref "second" "first" git symbolic-ref "nested/third" "second" git symbolic-ref "refs/heads/fourth" "nested/third" And the following shell code correctly resolves the latest created symbolic reference to the tip of master. git show-ref "refs/heads/fourth" None of these use cases are described in the official documentation ( git-symbolic-ref doc , git-show-ref doc ). However, the following doesn't work git check-ref-format --print "first" So, my questions are: Is it

In these days I have been playing with Java reflection and .class format. I'm currently studying ldc instruction. In JVM Specification I found term I don't understand: symbolic reference , and I have the following questions. What does it mean? Where is it used? In which cases does the ldc instruction load a symbolic reference? Is there any code in Java corresponding to that action? It would be helpful if you would quote the exact piece of the documentation that's giving you trouble. Since you haven't, I'm going to take a guess at what you might have quoted, from the doc for ldc : Otherwise, if