Another quick check on expression context for indexed expressions.
Please sanity-check the return value of want() below:

    @x[0] = want();   # scalar context
    @x[want()] = $_;  # scalar context
    @x[want()] = @_;  # scalar context
    @x[0,] = want();  # list context
    @x[want(),] = $_; # list context
    @x[want(),] = @_; # list context
    $_ = @x[want()];  # scalar context
    @_ = @x[want()];  # list context

Thanks,
/Autrijus/

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Oh, and under the S02 rules above (the index expression inherits
outer context on RHS), Pugs currently does this:

    $_ = %x{ 1, 2 }  
        --- reduces to ---
        $_ = %x{ [1, 2] }
            --- reduces to ---
            $_ = %x{ "1 2" }

Which is, well, very surprising.  Where did I get wrong?

Thanks,
/Autrijus/

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I think allowing unknown LHS index expression to default to
scalar context is a bit more useful here.  Since we have:

    @x[0]  = @y;        # scalar
    @x[0,] = @y;        # list

This may be more intuitive:

    @x[idx()]  = @y;    # scalar
    @x[idx(),] = @y;    # list

Than this:

    @x[+idx()] = @y;    # scalar
    @x[idx()]  = @y;    # list

But I don't really feel strongly one way or another, as long
as it is specced down. :)

Thanks,
/Autrijus/

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: Another quick check on expression context for indexed expressions.
: Please sanity-check the return value of want() below:
:
:     @x[0] = want();   # scalar context

Good.

:     @x[want()] = $_;  # scalar context
:     @x[want()] = @_;  # scalar context

Maybe "unknown" context, which defaults to list.

:     @x[0,] = want();  # list context
:     @x[want(),] = $_; # list context
:     @x[want(),] = @_; # list context
:     $_ = @x[want()];  # scalar context
:     @_ = @x[want()];  # list context

No, I think they're all list context.

Larry

: On Tue, Apr 26, 2005 at 03:33:44AM +0800, Autrijus Tang wrote:
: > Another quick check on expression context for indexed expressions.
: > Please sanity-check the return value of want() below:
: >
: >     @x[0] = want();      # scalar context
: >     @x[want()] = $_;     # scalar context
: >     @x[want()] = @_;     # scalar context
: >     @x[0,] = want();     # list context
: >     @x[want(),] = $_; # list context
: >     @x[want(),] = @_; # list context
: >     $_ = @x[want()];     # scalar context
: >     @_ = @x[want()];     # list context
:
: Oh, and under the S02 rules above (the index expression inherits
: outer context on RHS), Pugs currently does this:
:
:     $_ = %x{ 1, 2 }  
:       --- reduces to ---
:       $_ = %x{ [1, 2] }
:           --- reduces to ---
:           $_ = %x{ "1 2" }
:
: Which is, well, very surprising.  Where did I get wrong?

I think S02 is probably wrong.  It should be unknown/list context.

Sorry for the short answers, but I'm in Russia behind a flakey network
connection, which is probably going away entirely at any moment (the
network connection, not Russia.) I can clarify more next week when
I get back.

Larry

Okay. r2478 has them reverted to the original form, which
inspects the declared return type of want() to see if it is a subtype
of Scalar; if it is, then it is taken as scalar context;
otherwise (or if multiple multisubs are possible), it defaults
to list context.

Thanks,
/Autrijus/

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