Re: How to make a variable in hard call.

This is probably the simplest way:

sub inputPin
{
  my $s = sprintf("Device::BCM2835::RPI_V2_GPIO_P1_%02d", $_[0]);
  return (\&$s)->();
}

inputPin(7);
inputPin(6);
etc..
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Comment on Re: How to make a variable in hard call. Download Code

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Re^2: How to make a variable in hard call. by ikegami (Patriarch) on May 10, 2023 at 03:12 UTC
First of all, it would be simpler to avoid misleading the user by using a hack to circumvent strictures. `sub input_pin { my $name = sprintf( "Device::BCM2835::RPI_V2_GPIO_P1_%02d", $_[0] ) +; no strict "refs"; return $name->(); }` [download] But consider the following version: `my @input_pin; for ( @Device::BCM2835::EXPORT_OK ) { next if !/^RPI_V2_GPIO_P1_(\d+)\z/; my $pin = 0 + $1; my $val = do { no strict "refs"; "Device::BCM2835::$_"->() }; $input_pin[ $pin ] = $val; }` [download] This version allows us to do `$input_pin[3] $input_pin[5] $input_pin[7] ...` [download] instead of the slower `input_pin(3) input_pin(5) input_pin(7)` [download] So what if it's not the simplest? Update: The point of the first half is that using `no strict` version is simpler, but it originally said the opposite! woops. And sprintf was misspelled.	[reply] [d/l] [select]

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Re^2: How to make a variable in hard call.
by ikegami (Patriarch) on May 10, 2023 at 03:12 UTC

First of all, it would be simpler to avoid misleading the user by using a hack to circumvent strictures.

sub input_pin {
   my $name = sprintf( "Device::BCM2835::RPI_V2_GPIO_P1_%02d", $_[0] )
+;
   no strict "refs";
   return $name->();
}
[download]

But consider the following version:

my @input_pin;
for ( @Device::BCM2835::EXPORT_OK ) {
   next if !/^RPI_V2_GPIO_P1_(\d+)\z/;
   my $pin = 0 + $1;
   my $val = do { no strict "refs"; "Device::BCM2835::$_"->() };
   $input_pin[ $pin ] = $val;
}
[download]

This version allows us to do

$input_pin[3]
$input_pin[5]
$input_pin[7]
...
[download]

instead of the slower

input_pin(3)
input_pin(5)
input_pin(7)
[download]

So what if it's not the simplest?

Update: The point of the first half is that using no strict version is simpler, but it originally said the opposite! woops. And sprintf was misspelled.

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