Re: Not understanding 2 sentences in perldoc

List assignment:

my ($x, $y, $z) = qw( 1 2 3 );
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List assignment in list context produces a list of lvalues:

(my ($x, $y, $z) = qw( 1 2 3 )) = qw( a b c ); # $x = 'a', $y = 'b', $
+z = 'c'.
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List assignment in scalar context:

print scalar (my ($x, $y, $z) = qw( a b c d ));  # 4
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Modifying a scalar assignment:

($x = 12) =~ s/1/4/; print $x;  # 42
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map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

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Re^2: Not understanding 2 sentences in perldoc by Anonymous Monk on Jul 29, 2020 at 20:23 UTC
List assignment in list context produces a list of lvalues: `(my ($x, $y, $z) = qw( 1 2 3 )) = qw( a b c ); # $x = 'a', $y = 'b', $z = 'c'.` What is the lvalues here?	[reply] [d/l]
Re^3: Not understanding 2 sentences in perldoc by LanX (Saint) on Jul 29, 2020 at 20:28 UTC
> What is the lvalues here? ($x, $y, $z) are after the first assignment ready for the second one. Lvalue means left value of assignment (the recipient) See also `perlglossary` lvalue Term used by language lawyers for a storage location you can assign a new value to, such as a variable or an element of an array. The “l” is short for “left”, as in the left side of an assignment, a typical place for lvalues. An lvaluable function or expression is one to which a value may be assigned, as in pos($x) = 10 . Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]
Re^4: Not understanding 2 sentences in perldoc by Anonymous Monk on Jul 29, 2020 at 20:37 UTC
"($x, $y, $z) are after the first assignment ready for the next one." The next one is the assignment to `qw( a b c );` ? And what happens to `qw( 1 2 3 )` in `(my ($x, $y, $z) = qw( 1 2 3 )) = qw( a b c ); # $x = 'a', $y = 'b', $z = 'c'.` ?	[reply] [d/l] [select]
Re^5: Not understanding 2 sentences in perldoc by haukex (Archbishop) on Jul 29, 2020 at 20:40 UTC
Re^6: Not understanding 2 sentences in perldoc by LanX (Saint) on Jul 29, 2020 at 21:35 UTC
Some notes below your chosen depth have not been shown here
Re^4: Not understanding 2 sentences in perldoc by Anonymous Monk on Jul 29, 2020 at 20:52 UTC
haukex posted "The assignment my ($x, $y, $z) = qw( 1 2 3 ) happens first, i.e. those three variables are assigned the numbers 1 to 3, and this first assignment returns the lvalues, to which the values qw( a b c ) are immediately assigned." "and this first assignment returns the lvalues" What lvalues does it return? I see `(my ($x, $y, $z) = qw( 1 2 3 )) = qw( a b c );` as `# 1 = 'a', 2 = 'b', 3 = 'c'.`	[reply] [d/l] [select]
Re^5: Not understanding 2 sentences in perldoc by LanX (Saint) on Jul 29, 2020 at 21:26 UTC
Re^6: Not understanding 2 sentences in perldoc by zapdos (Sexton) on Jul 29, 2020 at 22:01 UTC
Some notes below your chosen depth have not been shown here
Re^5: Not understanding 2 sentences in perldoc by haukex (Archbishop) on Jul 29, 2020 at 20:54 UTC
Re^2: Not understanding 2 sentences in perldoc by perlfan (Vicar) on Jul 29, 2020 at 21:02 UTC
Re^3: Not understanding 2 sentences in perldoc by perlfan (Vicar) on Jul 29, 2020 at 20:48 UTC
`# \| inner assignment with a LHS (l) and RHS (r) # llllllllll..v...rrrrrrr # + $x = 1, $y = 2, $z = 3. (my ($x, $y, $z) = ( 1, 2, 3 )) = ('a', 'b', 'c' ); # llllllllll.................^..rrrrrrrrrrrrr # + $x = 'a', $y = 'b', $z = 'c'. # \| outter assignment with a LHS (l) a +nd RHS (r)` [download] Slightly changed the internal scalar semantics by eliminating `qw`.	[reply] [d/l] [select]
Re^2: Not understanding 2 sentences in perldoc by perlfan (Vicar) on Jul 29, 2020 at 21:18 UTC
For my own edificiation, would we expect B::Deparse to have broken this down further? This was my first attempt to decompose it. perl -MO=Deparse -e '(my ($x, $y, $z) = qw( 1 2 3 )) = qw( a b c )' (my($x, $y, $z) = ('1', '2', '3')) = ('a', 'b', 'c'); -e syntax OK	[reply]


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