#!/usr/bin/env perl
#
# 10 - add 10 to the stack in base 2, 8, 10, and 16

use 5.32.0;
use warnings;
use experimental 'signatures';
use Carp 'croak';
use Language::Eforth;
our $f = Language::Eforth->new;

my $base = 10;
for my $newbase (qw(2 8 10 16)) {
    my $enc = inbase( $newbase, $base );
    $f->eval("$enc base !\n10\n");
    $base = $newbase;
}
# back to base 10 - embed supports $hexnumber for literal input,
# probably better than the inbase conversion (but less educational)
$f->eval( '$A base !' . " .s\n" );

# this could also be done with an "alphabet", see Number::AnyBase; ANS
# FORTH and Common LISP however restrict the base to 2..36
sub inbase ( $n, $base = 10 ) {
    croak "N must be positive"              if $n < 0;
    croak "base must be in the range 2..36" if $base < 2 or $base > 36;
    return $n                               if $base == 10;
    my $str = '';
    while (1) {
        my $mod = $n % $base;
        $n = int( $n / $base );
        # PORTABILITY not everything uses ASCII
        $mod = chr( 55 + $mod ) if $mod > 9;
        $str = $mod . $str;
        last if $n == 0;
    }
    return $str;
}