calc

#!/usr/bin/perl

use POSIX ;
use Term::ReadLine;

$init = '####################   numerical constants  ####################
$pi = 3.14159265358979	;	# pi [ acos(0)*2 ]
$e  = 2.71828182845905	;	# base of natural logarithm [ exp(1) ]
####################   physical constants   ####################
$h  = 6.6260755e-27	;	# Planck constant [erg s]
$k  = 1.380658e-16	;	# Boltzmann constant [erg/K]
$G  = 6.67259e-8	;	# gravitational constant [dyne cm^2 g^-2]
$c  = 2.99792458e10	;	# velocity of light [cm/s]
$me = 9.1093897e-28	;	# mass of electron [g]
$mp = 1.6726231e-24	;	# mass of proton [g]
$mu = 1.6605402e-24	;	# atomic mass unit [g]
$Na = 6.0221367e23	;	# [mol^-1]
$R  = 8.314510e+7	;	# [erg mol^-1 K^-1]
$ev = 1.60217733e-12	;	# electron volt [erg]
#################### astronomical constants ####################
$yr = 3.1556926e7	;	# solar year [s]
$au = 1.49597870e13	;	# astronomical unit [cm]
$sec= 4.8481368e-06	;	# second [rad]
$pc = 3.08e18		;	# persec [cm] 3.08567756705283e18 cm ?
$ly = 9.46e17		;	# light year [cm]
$rs = 6.96e10		;	# radius of the sun [cm]
$ms = 1.9891e33		;	# mass of the sun [g]
$ls = 3.85e33		;	# luminosity of the sun [erg/s]
$re = 6.378e8		;	# radius of the earth [cm]
$me = 5.974e27		;	# mass of the earth [g]
# mathematical library functions are included (see also \"man 3 math\")
';

print $init;
eval $init;

if(open(FP,"$ENV{HOME}/.calcrc")){
   while(<FP>){print; eval $_;}
   close FP;
}

$term = new Term::ReadLine 'Simple Perl calc', \*STDIN, \*STDOUT;
$prompt = "calc\> ";
$OUT = $term->OUT || STDOUT;

while ( defined ($_ = $term->readline($prompt, "")) ) {
  $res = eval($_);
  warn $@ if $@;
  print $OUT $res, "\n" unless $@;
}