in reply to Re^3: What am I not understanding about $,
in thread What am I not understanding about $,
Why should Perl special variables get a pass on that?
If you, as a "former monk" don't understand, then it both explains why you left; and why nothing I could possibly say would make the slightest bit of difference to your perception of this situation.
The key indicator here is your phrase: "Mutating global state is bad."
By which you mean: varying variables with top level scope. is verboten; (by you!)
- There is no point in having variables; if you cannot vary them!
Variables that do not; or are not "permitted" to, vary, are constants.
(It is this, beyond the performance penalties, that make Readonly a nonsense.)
- Every program has a 'top level scope'.
Choosing to differentiate between "global variables" and "top level, lexical variables" is a sham. A pointless and puerile non-distinction.
Further, every (useful) program ever written makes some assumptions about ... whatever. This is usually referred to as "configuration".
So your (bland and uninteresting; unless you bother to follow up with some supporting argument) statement reduces to: is there any legitimate reason for a program to ever override its startup assumptions?
And fine, if you can sit wherever you are, and hand-on-heart, conclude that there is never a legitimate reason for a program to override its startup assumptions; then you've won the argument.
But, before you pat yourself on the back consider each of these:
- Have you never written a program that needed to override the default assumption about what constitutes a newline?
Eg. A *nix program that used sockets.
- Have you never written a program that needed (or benefited from) overriding the default value of cwd?
- Have you never written a program that benefited from overriding the default setting of STDIN, STDOUT or STDERR?
You've never used the one-arg form of select; nor redirected STDERR to a log file?
- You've never messed with %INC?
Eg, used lib?
- You've never tweaked %ENV?
- How about installed your own signal handler in %SIG?
- You've never felt the need to reset $@, $!, $^E, and $? before running code that might influence them; and which you need to make decisions upon the values they might acquire?
- Have you never written a program that needed to override the default assumption about what constitutes a newline?
If you can say "No" to all of those; then you've both won the argument, and are either a liar; or not a programmer.
Being selective about what functionality you accept as legitimate, and what you personally choose to reject is one thing; attempting to impose your affectations upon the world at large is another.