#perl.br calc - A Perl Shell
ruoso
created: 2006-05-31 14:05:02

Using a trick by [node://fglock], and with the help of the guys at #perl.br (at freenode.org), here is the #perl.br calc, which I now use in place of bc...

Obviously, you'll see it's just a Perl Shell that have some calculator shortcuts, so, you can do whatever you want with it...

#!/usr/bin/perl

use strict;
use warnings;
use Term::ReadLine;

my $name = '#perl.br calc';
print $name.$/;
my $term = Term::ReadLine->new($name);
$term->Features()->{'autohistory'} = 1;
my $prompt = "> ";
my $OUT = $term->OUT || \*STDOUT;

my $___eval_str___;
my $M = 0;
my $scale = 2;

sub ler {
        my $a = $term->readline($prompt);
        unless (defined $a) {
                print $/;
                exit(0);
        }
        return $a;
}

sub substituir {
        my $a = shift;
        $a =~ s/^(.+)(\*\*)$/\$M $2 $1/;
        $a =~ s/^(.+)(\+|\-|\*|\/)$/\$M $2 $1/;
        $a =~ s/\;\s*$//;
        if ($a =~ /^\s*do {\s*$/) {
                my $block = '';
                my $count = 1;
                while (defined($_=$term->readline(' '.('.'x$count).' '))) {
                        while ($_ =~ m/\{/g) {
                                $count++;
                        }
                        while ($_ =~ m/\}/g) {
                                $count--;
                        }
                        last if $count < 1;
                        $block .= $_;
                }
                $a = 'do {'.$block.'}';
        }
        return $a;
}

sub falar {
        my $a = shift;
        if ($@) {
                print "! ".$@;
        } else {
                if (defined $a && $a =~ /^[\d\.]$/) {
                        $M=sprintf("%.".$scale."f",$a);
                } elsif ($a) {
                        $M=$a;
                }
                print $OUT "= ".$M.$/ if defined $M;
        }
}

sub doit {
        $___eval_str___ = '
eval("
   falar(".substituir(ler()).");
   $___eval_str___;
");
if($@){
   print "! ".$@;
   eval($___eval_str___)
}
';
        eval $___eval_str___;
}

doit();
daniel
Re: #perl.br calc - A Perl Shell
created: 2006-05-31 15:42:15
I ran this on Windows XP SP2 using ActiveState 5.8.7 and got this error message:
SetConsoleMode failed, LastError=|6| at c:/Perl/site/lib/Term/ReadKey.pm line 265.
Re^2: #perl.br calc - A Perl Shell
created: 2006-05-31 16:35:05

try without the $term->Features() line... If that still doesn't work, file a bug report against Term::ReadLine, or Term::ReadKey, or ActiveState...

BTW... you still can try changing the $term->readline() for <STDIN>, i think.

daniel
Re: #perl.br calc - A Perl Shell
created: 2006-06-01 03:28:08
run fine on w2k SP4 perl, v5.8.6 built for MSWin32-x86-multi-thread ActiveState. ty
Re: #perl.br calc - A Perl Shell
created: 2006-06-01 03:56:44
Perl, computing... hmm ;-) Compare these:
$ echo 'x=y=1.2; x+=1.1; x-=1.1; x; y; x==y' |bc |xargs echo
1.2 1.2 1
$ perl -wle '$x=$y=1.2; $x+=1.1; $x-=1.1; $,=$"; print $x, $y, $x == $y'
1.2 1.2
don't you love perl? ;-)
Re^2: #perl.br calc - A Perl Shell
created: 2006-06-01 05:02:04

As a quick calculator (especially with vector/matrix ops) I like the J programming language. It's not quite good as a real programming language IMO, but it's ideal for doing some quick numeric computations. GNU octave is good for the same purpose as well.

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