Re: How can I print variable contents from the debugger non-interactively? ( a = line action ; w = watch changes everywhere)

> to print all the variable contents when executing line XXX

some hands on examples

a action (per line) and w watchpoint (each time) take Perl code to be evaluated.

you can do pretty nifty things with that already

sample code

use strict;
use warnings;
$|=1;            # disable buffering

my $a;
our $y;


for (0..10) {
   print;
   $a++;
   $y++;
}
[download]

a = action cmd on line

DB<71> h a
a [line] command
        Set an action to be done before the line is executed;
        line defaults to the current execution line.
        Sequence is: check for breakpoint/watchpoint, print line
        if necessary, do action, prompt user if necessary,
        execute line.
a        Does nothing
[download]

a doesn't break unless you set $DB::single explicitly to 1

  DB<72> a 10 if($y>3 and $y <7) { print "\n<y: $y>\n" }

  DB<73> L
d:/Users/RolfLangsdorf/AppData/Roaming/pm/tst_debuger.pl:
 10:       print;
   action:  if($y>3 and $y <7) { print "\n<y: $y>\n" }
  DB<73> c
0123
<y: 4>
4
<y: 5>
5
<y: 6>
678910  
  DB<74>
[download]

w = watch-expression

  DB<79> h w
w expr        Add a global watch-expression.
w             Does nothing
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w stops if the returned value has changed

w $a would stop each time $a is changing

this only stops if $a is inside the intervall

  DB<81> L
  DB<81> w if ($a>3 and $a <7){ $a }
  DB<82> c
0123Watchpoint 0:    if ($a>3 and $a <7){ $a } changed:
    old value:    ''
    new value:    '4'
  DB<82> c
4Watchpoint 0:    if ($a>3 and $a <7){ $a } changed:
    old value:    '4'
    new value:    '5'
  DB<82> 

  DB<82> c
5Watchpoint 0:    if ($a>3 and $a <7){ $a } changed:
    old value:    '5'
    new value:    '6'
  DB<82> c
6Watchpoint 0:    if ($a>3 and $a <7){ $a } changed:
    old value:    '6'
    new value:    ''
  DB<82> c
78910  DB<82>
[download]

this only stops for the first print and the first non print (print returns 1)

  DB<78> w if ($a>3 and $a <7){ print "\n$DB::line<a: $a>\n" }
  DB<79> L
Watch-expressions:
 if ($a>3 and $a <7){ print "\n$DB::line<a: $a>\n" }
  DB<79> c
0123
12<a: 4>
Watchpoint 0:    if ($a>3 and $a <7){ print "\n$DB::line<a: $a>\n" } c
+hanged:
    old value:    ''
    new value:    '1'
  DB<79> c

10<a: 4>
4
11<a: 4>

12<a: 5>

10<a: 5>
5
11<a: 5>

12<a: 6>

10<a: 6>
6
11<a: 6>
Watchpoint 0:    if ($a>3 and $a <7){ print "\n$DB::line<a: $a>\n" } c
+hanged:
    old value:    '1'
    new value:    ''
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Je suis Charlie!}

Comment on Re: How can I print variable contents from the debugger non-interactively? ( a = line action ; w = watch changes everywhere) Select or Download Code

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Re^2: How can I print variable contents from the debugger non-interactively? ( b= break line conditionally ) by LanX (Saint) on Jul 15, 2017 at 11:42 UTC
b for break also takes code like in a you can execute code Perl line, just return something false if you don't want to break into interactive mode `DB<119> b 11 print "\n<$y>\n" if $y==3;0 DB<120> L d:/Users/RolfLangsdorf/AppData/Roaming/pm/tst_debuger.pl: 11: $a++; break if (print "\n<$y>\n" if $y==3;0) DB<120> c 0123 <3> 45678910 DB<120>` [download] Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply] [d/l]

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Re^2: How can I print variable contents from the debugger non-interactively? ( b= break line conditionally )
by LanX (Saint) on Jul 15, 2017 at 11:42 UTC

like in a you can execute code Perl line, just return something false if you don't want to break into interactive mode

  DB<119> b 11 print "\n<$y>\n" if $y==3;0
  DB<120> L
d:/Users/RolfLangsdorf/AppData/Roaming/pm/tst_debuger.pl:
 11:       $a++;
   break if (print "\n<$y>\n" if $y==3;0)
  DB<120> c
0123
<3>
45678910  DB<120>
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Je suis Charlie!}

[reply]
[d/l]