Noob question: Is all this typecasting normal?

[Roy Smith]

In article 
<cc87ebf5-5ce1-4fb5-bb2d-cd4bc2426ce3 at q36g2000vbn.googlegroups.com>,
 sprad <jsprad at gmail.com> wrote:

> On Jan 3, 6:41 pm, Steven D'Aprano <st... at REMOVE-THIS-
> cybersource.com.au> wrote:
> > The OP comes from a Perl background, which AFAIK allows you to concat
> > numbers to strings and add strings to numbers. That's probably the (mis)
> > feature he was hoping Python had.
> 
> That's correct -- and that's been one of the more difficult parts of
> my transition. Learned C++ in college, spent a few years doing Perl,
> and now all of a sudden type matters again. It's a very different
> philosophy, but I'm determined to stick with it until I have an Aha!
> moment and find something I can do more easily than I can with Perl.

The Aha! moment comes 6 months from now, when you discover that you can 
understand the Python code you wrote 6 months ago, but the Perl code you 
wrote at the same time has become gibberish, even to you.

The other day, I came upon this gem.  It's a bit of perl embedded in a 
Makefile; this makes it even more gnarly because all the $'s get doubled to 
hide them from make:

define absmondir
$(shell perl -e ' \                                                         
                                  
sub absmon { my $$a = $$_[0]; \                                             
                                  
   if ( $$^O =~ m/cygwin|MSWin32/i ) {                                     
                                   
      $$prefix = `/bin/mount -p|awk "NR==2{print \\\$$1}"`; 
chomp($$prefix); \
      $$a = ($$_[1]||"$(PWD)") . "/$$a" \
         unless ( $$a =~ m !^(:?$$prefix|/|[A-Za-z]:)! ); \
   } else { $$a = ($$_[1]||"$(PWD)") . "/$$a" unless ( $$a =~ m !^/! ); } \
   return unslash(undot(undotdot($$a))); }; \
sub unslash ($$) { $$_[0] =~ s://+:/:g; $$_[0] =~ s:/$$::; return($$_[0]); 
}; \
sub undot ($$) { $$_[0]=~s:/\./:/:g; return ($$_[0]); }; \
sub undotdot ($$) { my $$in = $$_[0]; \
      return ( $$in =~ s:/[^/.][^/]*/\.\.::g )?undotdot($$in):$$in; }; \
print absmon("$(1)","$(2)"); \
' )                                                                         
                                  
endef

Barf-o-rama.  I know what it's supposed to do, and I still can't figure it 
out.