use strict;
use warnings;
use Test::More;
BEGIN { plan tests => 15 }
use Math::Expression::Evaluator;
my $m = new Math::Expression::Evaluator;
ok($m, "new works");
sub e {
    return $m->parse(shift)->val();
}
sub c {
    return &{$m->parse(shift)->compiled}();
}
is e('a = 3'),      3,  'Assignment returns value';
is e('a'),          3,  'Variables persistent';
is e('a*a'),        9,  'Arithmetics with variables';
#reset old variable values
$m = Math::Expression::Evaluator->new();
is c('a = 3; a*a'), 9,  'Assignment returns value (compiled)';
$m->parse("a + b");
is $m->val({a => 1, b => 2}), 3, 'externally assigned variables';
$m->parse("a = 3; a");
is $m->val({a => 1}),   1,  'externally provided variables override internal ones';
# test that assignments in an expression don't modify the hash passed to
# the 'val' or the compiled function;
my $vars = { a => 1 };
$m->parse('a = 2');
$m->val($vars);
is $vars->{a},          '1',    'no side effects on externally provided variables';
&{$m->compiled}($vars);
is $vars->{a},          '1',    'no side effects on externally provided variables [compiled]';
$m->parse(' b = 5')->val;
is &{$m->parse('b')->compiled}, 5, 'compiled expressions can use prev. defined variables';
{
    my $m = Math::Expression::Evaluator->new();
    $m->parse('2 + b');
    my $callback = sub {
        my $varname = shift;
        # called twice!
        is $varname, 'b', 'passed the correct var name to the callback';
        3;
    };
    $m->set_var_callback($callback);
    is $m->val(),        5, 'and the return value was used';
    is $m->compiled->(), 5, 'same with compiled form';
}
eval { $m->parse(' 3 + 8 = 5 ') };
ok $@, 'non-lvalue cannot be assigned to';
# vim: sw=4 ts=4 expandtab syn=perl