如何從Perl跟蹤中查看變量的值？

Question

我的目標是調試（一步一步）下面的sample.pl腳本。

問題：我沒有得到變量的實際值（$ top_number，$ x，$ total）。

我的問題：如何從跟蹤輸出中查看（$ top_number，$ x，$ total） 的實數整數值？

需要更改perl -d:Trace以獲取數字，而不是：$ top_number，$ x，$ total？從跟蹤輸出

例子：

[root@linux /tmp]# perl -d:Trace ./sample.pl 
>> ./sampl.pl:9: $top_number = 100; 
>> ./sampl.pl:10: $x = 1; 
>> ./sampl.pl:11: $total = 0; 
>> ./sampl.pl:12: while ($x <= $top_number) { 
>> ./sampl.pl:13:  $total = $total + $x; # short form: $total += $x; 
>> ./sampl.pl:14:  $x += 1;    # do you follow this short form? 
>> ./sampl.pl:13:  $total = $total + $x; # short form: $total += $x; 
>> ./sampl.pl:14:  $x += 1;    # do you follow this short form? 
>> ./sampl.pl:13:  $total = $total + $x; # short form: $total += $x; 
>> ./sampl.pl:14:  $x += 1;    # do you follow this short form? 
. 
. 

[root@linux /tmp]#more sample.pl script 

#!/usr/bin/perl 


$top_number = 100; 
$x = 1; 
$total = 0; 
while ($x <= $top_number) { 
    $total = $total + $x; # short form: $total += $x; 
    $x += 1;    # do you follow this short form? 
} 

print "The total from 1 to $top_number is $total\n"; 

Answer 1

我假設你想看到的$x和$total變量的值，通過循環每次迭代。 POD沒有跡象表明Devel::Trace可以做到這一點。

但是，Devel::DumpTrace可以。

perl -d:DumpTrace ./sample.pl 

>>>>> hw.pl:7:  $top_number:100 = 100; 
>>>>> hw.pl:8:  $x:1 = 1; 
>>>>> hw.pl:9:  $total:0 = 0; 
>>>>> hw.pl:10:  while ($x:1 <= $top_number:100) { 
>>>>> hw.pl:11:   $total:1 = $total:0 + $x:1; # short form: $total:0 += $x:1; 
>>>>> hw.pl:12:   $x:2 += 1;    # do you follow this short form? 
>>>>> hw.pl:11:   $total:3 = $total:1 + $x:2; # short form: $total:1 += $x:2; 
>>>>> hw.pl:12:   $x:3 += 1;    # do you follow this short form? 
>>>>> hw.pl:11:   $total:6 = $total:3 + $x:3; # short form: $total:3 += $x:3; 

Answer 2

看一看Variable::Magic。它可能是變量「追蹤」的解決方案。