Re: Perl Concatenate vs Append Operator

Hi,

just as an addition. Compare the output of:

perl -MO=Terse -E'my $str = "McA"; $str = $str . " ";'
[download]

and

perl -MO=Terse -E'my $str = "McA"; $str .= " ";'
[download]

So the internal way of handling this (tried with Perl 5.10.1) is the same.

Regards
McA

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Re^2: Perl Concatenate vs Append Operator by Anonymous Monk on Aug 19, 2014 at 18:08 UTC
But! `perl -MO=Terse -E'our $str; $str = $str . " ";'` [download] and `perl -MO=Terse -E'our $str; $str .= " ";'` [download]	[reply] [d/l] [select]
Re^3: Perl Concatenate vs Append Operator by McA (Priest) on Aug 19, 2014 at 18:47 UTC
Hi, I'm so used to lexical variables that I didn't think about that. That's really interesting. Thank you for that insight. McA	[reply]
Re^2: Perl Concatenate vs Append Operator by Laurent_R (Canon) on Aug 19, 2014 at 21:32 UTC
I just tried it on Perl 5.14, I do not get exactly the same thing with your two one-liners: $ perl -MO=Terse -E'my $str = "McA"; $str = $str . " ";' LISTOP (0x600153910) leave [1] OP (0x60007fdb0) enter COP (0x60006e3c0) nextstate BINOP (0x6001f1ea0) sassign SVOP (0x60006e2e0) const [3] PV (0x6001f2c08) "McA" OP (0x60006f890) padsv [1] COP (0x6001f7fe0) nextstate BINOP (0x6001f7fa0) concat [1] OP (0x600153980) padsv [1] SVOP (0x6001f7f60) const [4] PV (0x6001f2b78) " " -e syntax OK $ perl -MO=Terse -E'my $str = "McA"; $str .= " ";' LISTOP (0x600153910) leave [1] OP (0x60007fdb0) enter COP (0x60006e3c0) nextstate BINOP (0x6001f1ea0) sassign SVOP (0x60006e2e0) const [3] PV (0x6001f2c08) "McA" OP (0x60006f890) padsv [1] COP (0x6001f7f60) nextstate BINOP (0x6001539c0) concat [2] OP (0x600153950) padsv [1] SVOP (0x600153980) const [4] PV (0x6001f2b78) " " -e syntax OK [download] There are some differences on the ante-penultimate and penultimate lines. But I am not really able to assess whether the difference is significant. The Deparse module also gives different output for these two lines in Perl 5.14.	[reply] [d/l]