logic-interpreter

namespace App;

use A1812\LogicInterpreter\AndExp;
use A1812\LogicInterpreter\Context;
use A1812\LogicInterpreter\ImplicationExp;
use A1812\LogicInterpreter\NotExp;
use A1812\LogicInterpreter\VariableExp;
use A1812\LogicInterpreter\Visitor\SignVisitor;
use A1812\LogicInterpreter\Visitor\StringVisitor;

require 'vendor/autoload.php';

$context = new Context();

$a = new VariableExp('A');
$b = new VariableExp('B');

/*
 * NOT((A → B) AND (B → A))
 *
 * from https://logic-proof.symfony.site/186
 *
 * Case A  B  ~ ((A → B) ∧ (B → A))
 * 1    T  T  F
 * 2    T  F  T
 * 3    F  T  T
 * 4    F  F  F 
 */

$exp = new NotExp(
    new AndExp(
        new ImplicationExp($a, $b),
        new ImplicationExp($b, $a)
    )
);

$context
    ->assign($a, true)
    ->assign($b, false)
;

// output: "(NOT ((A IMPLICATION B) AND (B IMPLICATION A)))"
echo $exp->accept(new StringVisitor());

// output: " = true" 
echo ' = ' . $exp->interpret($context) ? 'true' : 'false' . PHP_EOL;

$context
    ->assign($a, true)
    ->assign($b, true)
;

// output: "(NOT ((A IMPLICATION B) AND (B IMPLICATION A)))"
echo $exp->accept(new StringVisitor());

// output: " = false"
echo ' = ' . $exp->interpret($context) ? 'true' : 'false' . PHP_EOL;

// output: (~ ((A → B) ∧ (B → A)) - false
echo $exp->accept(new SignVisitor()) . ' = ' . ($exp->interpret($context) ? 'true' : 'false') . PHP_EOL;