#!/usr/bin/perl
# Script making it easier to run the various Perl 6 implementations.
# Hides what directory you need to be in, and executable invocation.
# The assorted command-lines are _not_ normalized.  That's a task for
# a different next-generation script.
use strict;
use warnings;

sub require_PUGS_ROOT {
    if(not $ENV{PUGS_ROOT}) {
	die "You must set the environment variable PUGS_ROOT .\n";
    }
}
sub require_PARROT_ROOT {
    if(not $ENV{PARROT_ROOT}) {
	die "You must set the environment variable PARROT_ROOT .\n";
    }
}

sub print_usage_and_exit {
    print STDERR <<"END";
$0 PERL6_IMPLEMENTATION ARGUMENTS

PERL6_IMPLEMENTATION can be
  pugs
  kp6
  rakudo
  rakudo.exe
  rakudo.pbc
  redsix

Several interpreters require chdir()ing before running them.
ARGUMENTS which are guessed to be relative filenames have the
current working directory prepended to them.

END
    exit(2);
}

sub main {
    print_usage_and_exit if !@ARGV;
    my $impl = shift(@ARGV);
    my @args = absolutize_any_file_names(@ARGV);
    $impl = 'rakudo.exe' if $impl eq 'rakudo';
    if($impl eq 'pugs') {
	require_PUGS_ROOT;
	# Needs chdir() to find it's precompiled prelude, yes?
	chdir($ENV{PUGS_ROOT}) or die $!;
	exec("./pugs",@args);
    }
    elsif($impl eq 'kp6') {
	require_PUGS_ROOT;
	# Needs chdir() to find... what? XXX
	chdir($ENV{PUGS_ROOT}.'/v6/v6-KindaPerl6') or die $!;
	exec("./script/kp6",@args);
    }
    elsif($impl eq 'redsix') {
	require_PUGS_ROOT;
	# Needs chdir() to find its own Test.pm.
	#exec($ENV{PUGS_ROOT}.'/misc/pX/Common/redsix/redsix',@ARGV);
	chdir($ENV{PUGS_ROOT}.'/misc/pX/Common/redsix') or die $!;
	exec("./redsix",@args);
    }
    elsif($impl eq 'rakudo.pbc') {
	require_PARROT_ROOT;
	# XXX Entirely speculative.
	chdir($ENV{PARROT_ROOT}.'/languages/perl6') or die $!;
	exec("../../parrot","perl6.pbc",@args);
    }
    elsif($impl eq 'rakudo.exe') {
	require_PARROT_ROOT;
	# XXX Entirely speculative.
	chdir($ENV{PARROT_ROOT}.'/languages/perl6') or die $!;
	die "It looks like you forgot to build the perl6 executable in rakudo?"
	    if(!-e "./perl6");
	exec("./perl6",@args);
    }
    else {
	print STDERR "\nUnknown implementation: $impl\n\n";
	print_usage_and_exit;
    }
}

sub absolutize_any_file_names {
    my(@args)=@_;
    chomp(my $cwd = `pwd`);
    for my $i (0..(@args-1)) {
	my $arg = $args[$i];
	my $seems_to_be_a_file = 
	    (-e $arg or
	     ($arg =~ /\// && ($i == 0 || $args[$i-1] ne '-e')));
	next if not $seems_to_be_a_file;
	next if $arg =~ /^\//; # already an absolute path.
	$args[$i] = $cwd.'/'.$args[$i];
    }
    @args;
}

main;