Re^7: Assignable Subroutines

I had the wierdest of thoughts (ain't TMTOWTDI wonderful?) ...

sub update_thing
{
  my ($self, $x, $y, $u) = @_;
  if (ref $u and UNIVERSAL::isa($u, 'CODE'))
  {
    # use temp to keep the $u function from changing $_[0] ;-)
    my $val = $self->{cell}[$x][$y];
    $u = $u->($val);
  }
  # validate $u.
  if ($is_valid)
  {
    $self->{cell}[$x][$y] = $u;
}
[download]

called sorta like:

  $obj->update_thing(15000, 20000, sub { $_[0] =~ s[something][else]g;
+ $_[0] } );
[download]

No, not better than $obj->thing(15000,2000) =~ s[something][else]g. But a bit better than the other ideas going around, maybe? :-) If not better, at least different...

Comment on Re^7: Assignable Subroutines Select or Download Code

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Re^8: Assignable Subroutines by BrowserUk (Patriarch) on Jan 25, 2005 at 17:28 UTC
It's a fine notion but it has it's problems. You now, need to code a `get_thing()` method; `print $obj->thing;` [download] a `set_thing()` method; `$obj->thing = 'someting';` [download] a `update_thing()` method; `$obj->thing =~ s[this][that]g;` [download] a `return_list_of_matched_subthings()` method; `my @subthings = $obj->thing =~ m[subthing]g;` [download] a `return_count_of_subthings()` method; `my $count = $obj->thing =~ m[subthing]g;` [download] a `get_subthing_iterator()` method; `while( $obj->thing =~ m[subthing]g ) { last if substr( $obj->thing, pos( $obj->thing ) - 22, 22 ) eq 'This is the subthing'; }` [download] (Oh! And a `substr_thing()` method;) a `preincr_thing()` method; `$obj->thing++;` [download] A `postincr_thing()` method; `++$obj->thing;` [download] (pre/post decr etc. etc) And all the others that you effectively get for free with a single lvalue method. All that is missing is a convenient way to validate the assignment. Examine what is said, not who speaks. Silence betokens consent. Love the truth but pardon error.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^8: Assignable Subroutines
by BrowserUk (Patriarch) on Jan 25, 2005 at 17:28 UTC

It's a fine notion but it has it's problems.

You now, need to code

a get_thing() method;
```
print $obj->thing;
[download]
```
a set_thing() method;
```
$obj->thing = 'someting';
[download]
```

a update_thing() method;

$obj->thing =~ s[this][that]g;
[download]

a return_list_of_matched_subthings() method;

my @subthings = $obj->thing =~ m[subthing]g;
[download]

a return_count_of_subthings() method;

my $count = $obj->thing =~ m[subthing]g;
[download]

a get_subthing_iterator() method;

while( $obj->thing =~ m[subthing]g ) {
    last if substr( $obj->thing, pos( $obj->thing ) - 22, 22 ) 
         eq 'This is *the* subthing';
}
[download]

(Oh! And a substr_thing() method;)

a preincr_thing() method;
```
$obj->thing++;
[download]
```
A postincr_thing() method;
```
++$obj->thing;
[download]
```
(pre/post decr etc. etc)

And all the others that you effectively get for free with a single lvalue method.

All that is missing is a convenient way to validate the assignment.

Examine what is said, not who speaks.

Silence betokens consent.

Love the truth but pardon error.

[reply]
[d/l]
[select]