Re: perl5db.pl improvements: apply user's context pragma while DB::eval

[Shlomi Fish]

Hi KES,

First of all, note that you should not E-mail me at shl...@iglu.org.il. E-mail
me only at shl...@shlomifish.org . Where did you find the @iglu.org.il address?

See below for the rest of my reply.

On Mon, 28 Mar 2016 11:21:10 +0300
KES <kes...@yandex.ru> wrote:

> Hi.
>
> When from debugger we evaluate some expression the user's context pragma is
> not applyed.
>
> This patch fixes that:
> https://github.com/KES777/perl/tree/apply_users_context_pragma
>

I'm not sure I understand. Can you also include new test assertions (see
lib/perl5db.t and lib/perl5db/t/ in the Perl distribution) that will fail
before the changes to the production code and will pass after applying them?
See:

* https://en.wikipedia.org/wiki/Test-driven_development

* http://perl-begin.org/uses/qa/

>
> Need help with one problem, can not watch variables when the debugging
> script.pl has 'use strict' in effect.
>
> Variable "$x" is not imported at (eval 10)[./perl5db.pl:740] line 1.
> at (eval 10)[./perl5db.pl:740] line 1.
> eval 'BEGIN{ ( $^H, ${^WARNING_BITS} ) = @DB::saved[7,8]; }($@, $!,
> $^E, $,, $/, $\\, $^W) = @DB::saved;package main; $x; ' called
> at ./perl5db.pl line 740 DB::eval called at ./perl5db.pl line 6051
> DB::_add_watch_expr("\$x") called at ./perl5db.pl line 6071
> DB::cmd_w("w", "\$x", 6) called at ./perl5db.pl line 4488
> DB::cmd_wrapper("w", "\$x", 6) called at ./perl5db.pl line 3999
> DB::Obj::_handle_cmd_wrapper_commands(DB::Obj=HASH(0x26593c0)) called
> at ./perl5db.pl line 2881 DB::DB called at /home/kes/tmp/t3.pl line 6
> Global symbol "$x" requires explicit package name (did you forget to declare
> "my $x"?) at (eval 10)[./perl5db.pl:740] line 1.
>

I don't understand.

> But here the design problem because of next:
> An eval '' executed within a subroutine defined in the DB package doesn't see
> the usual surrounding lexical scope, but rather the scope of the first non-DB
> piece of code that called it
>
> As we can see from stacktrace the 'first non-DB piece of code' is
> DB::Obj::_handle_cmd_wrapper_commands(DB::Obj=HASH(0x26593c0)) called
> at ./perl5db.pl line 2881
>
> So if we want $x be evaled at user's context the DB::DB *SHOULD NOT* call to
> DB::Obj namespace.

Not sure I understand (again). Can you provide a test case?

Regards,

Shlomi Fish


--
-----------------------------------------------------------------
Shlomi Fish

“Stop reinventing wheels, start building space rockets.”
— The motto of the Comprehensive Perl Archive Network

[KES]

Hi.

When from debugger we evaluate some expression the user's context pragma is not applyed.

This patch fixes that: https://github.com/KES777/perl/tree/apply_users_context_pragma

Need help with one problem, can not watch variables when the debugging script.pl has 'use strict' in effect.

Variable "$x" is not imported at (eval 10)[./perl5db.pl:740] line 1.
at (eval 10)[./perl5db.pl:740] line 1.
eval 'BEGIN{ ( $^H, ${^WARNING_BITS} ) = @DB::saved[7,8]; }($@, $!, $^E, $,, $/, $\\, $^W) = @DB::saved;package main; $x;
' called at ./perl5db.pl line 740
DB::eval called at ./perl5db.pl line 6051
DB::_add_watch_expr("\$x") called at ./perl5db.pl line 6071
DB::cmd_w("w", "\$x", 6) called at ./perl5db.pl line 4488
DB::cmd_wrapper("w", "\$x", 6) called at ./perl5db.pl line 3999
DB::Obj::_handle_cmd_wrapper_commands(DB::Obj=HASH(0x26593c0)) called at ./perl5db.pl line 2881
DB::DB called at /home/kes/tmp/t3.pl line 6
Global symbol "$x" requires explicit package name (did you forget to declare "my $x"?) at (eval 10)[./perl5db.pl:740] line 1.

[KES]

I have update branch. Do some fix and create testcase.

Now you can run
/perl/lib $ PERL5DB='BEGIN{ require "./perl5db.pl" }' perl -Iperl5db/t -d perl5db/t/apply_users_pragma_when_eval

ACTUAL RESULTS:
Loading DB routines from perl5db.pl version 1.49_03
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(perl5db/t/apply_users_pragma_when_eval:5):
5: my $l = MyMaths->new(1.2);
DB<1> n
main::(perl5db/t/apply_users_pragma_when_eval:6):
6: my $r = MyMaths->new(3.4);
DB<1> n
main::(perl5db/t/apply_users_pragma_when_eval:7):
7: print "A: ", $l + $r, "\n";
DB<1> n
A: 4.6
main::(perl5db/t/apply_users_pragma_when_eval:9):
9: print "B: ", $l + $r, "\n";
10: {
DB<1> n
B: 4 <<<<<<<<<<< NOTICE HERE
main::(perl5db/t/apply_users_pragma_when_eval:11):
11: no myint;
DB<1> print "B: ", $l + $r, "\n";
B: 4.6

BUT EXPECTED:
B: 4

http://perldoc.perl.org/perlpragma.html

A: 4.6
B: 4
C: 4.6
D: 4
E: 4.6


28.03.2016, 14:38, "Shlomi Fish" <shl...@shlomifish.org>: