Return value of STORE #14835
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From @vportonThis is a bug report for perl from porton@narod.ru, What is done with return value of STORE (with for example tied hashes)? What `$obj{FIELD} = 123;` returns if %obj is a tied hash? This is undocumented (not only for tied hashes, but also tied arrays, etc.) Flags: Site configuration information for perl 5.20.2: Configured by Debian Project at Fri May 15 11:27:53 UTC 2015. Summary of my perl5 (revision 5 version 20 subversion 2) configuration: Locally applied patches: @INC for perl 5.20.2: Environment for perl 5.20.2: |
From @jkeenanOn Sun Aug 02 10:08:10 2015, porton@narod.ru wrote:
Based on reading 'perldoc perltie', I would say that the return value of STORE is whatever is the return value of the method that you write to implement STORE. Thank you very much. -- |
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The RT System itself - Status changed from 'new' to 'open' |
From @vportonOn Sun, 2015-08-02 at 15:54 -0700, James E Keenan via RT wrote:
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From @tonycozOn Sun, Aug 02, 2015 at 10:08:11AM -0700, via RT wrote:
It should return $obj{FIELD}, like any other scalar assignment. Tony |
From @vportonOn Sun, 2015-08-02 at 16:54 -0700, Tony Cook via RT wrote:
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From @jkeenanOn Sun Aug 02 16:59:43 2015, porton@narod.ru wrote:
Could you submit a patch for consideration? Thank you very much. -- |
From @tonycozOn Mon, Aug 03, 2015 at 02:58:58AM +0300, Victor Porton wrote:
I'm not sure, and don't feel much need to test it. I'd expect it to
It's not as clear as it could be, and refers to the behaviour in C: Assignment operators work as in C. ... ... Unlike in C, the scalar assignment operator produces a valid lvalue. So you really need to know how a C assignment operator works to Tony |
From @iabynOn Sun, Aug 02, 2015 at 10:08:11AM -0700, via RT wrote:
It is discarded.
a key lookup of a tied hash, e.g. $obj{FIELD}, returns a temporary The scalar assign operator returns whatever was on its LHS - in this case For example in this code: $x = ($obj{FIELD} = 1); perl would call STORE() followed by FETCH(), while with this: ($obj{FIELD} = 1) = 2; STORE would be called twice. -- |
From @tonycozOn Sun Aug 02 10:08:10 2015, porton@narod.ru wrote:
The documentation for scalar STORE says: Don't worry about which implies any return value is ignored. A reader can make the reasonable assumption that applies to hash and array ties. I wonder if that could be re-worded to: Any return value from STORE is ignored; the semantic of assignment returning the and duplicated to the hash and array STORE documentation. Tony |
Migrated from rt.perl.org#125737 (status was 'open')
Searchable as RT125737$
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