DB<159> $a=inf
 => "inf"

  DB<160> --$a
 => "inf"

  DB<161> ++$a  
 => "inf"

  DB<162> ++$a  
 => "inf"

##</code><code>##

  DB<156> $a=inf
 => "inf"

  DB<157> ++$a  
 => "ing"

  DB<158> ++$a  
 => "inh"

##</code><code>##

  DB<174> $a=inf+0
 => "inf"

  DB<175> ++$a  
 => "inf"

  DB<176> ++$a  
 => "inf"

##</code><code>##

 perl -e '$a=inf; print ++$a,"\n"'
ing