http://www.perlmonks.org?node_id=995591


in reply to Data::Types or grok_number

use 5.010;
use Scalar::Util qw(looks_like_number);

sub is_int (_) {
  my $i = shift;
  looks_like_number($i) and int($i)==$i;
}

say for grep { is_int } qw(
    -6
    5.2
    5.0
    3e4
    0Hello
);

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Note that this classes 5.0 as an integer, which is correct from a maths point of view, but not necessarily from a comp sci one.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

Replies are listed 'Best First'.
Re^2: Data::Types or grok_number
by tqisjim (Beadle) on Sep 25, 2012 at 17:57 UTC

    I was thinking of something along the lines of the following:

      print TQIS::Primitive::typeis("1") ;
> string
  print TQIS::Primitive::typeis(1) ;
> integer

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    Here is the code: 
    #include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include "ppport.h"

SV* typeis ( SV* what ) ;

SV* typeis ( SV* what )
{
        if ( SvIOK( what ) )
                return newSVpvs( "integer" ) ;
        else if ( SvNOK( what ) )
                return newSVpvs( "double" ) ;
        else if ( SvPOK( what ) )
                return newSVpvs( "string" ) ;

        return newSVpvs( "unknown" ) ;
}


MODULE = TQIS::Primitive                PACKAGE = TQIS::Primitive

PROTOTYPES: ENABLE

SV*
typeis( what )
        SV* what

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