Logicandcompare (#50)

* TokenFactory: allowing multicharacter tokens

* Added logical and compare operators: <, <=, >, >=, ==, !=, ||, &&

* Fixed operator priorities

* Error messages fixes

* Fixed operators priority

The priorities are assigned by following the php language standard
(https://www.php.net/manual/en/language.operators.precedence.php)
I've assigned precedence in steps of 10 units by following the linked page:
230 clone new
220 **
210 ++ -- ~ (int) (float) (string) (array) (object) (bool) @
200 instanceof
190 !
180 * / %
170 + - .
160 << >>
150 < <= > >=
140 == != === !== <> <=>
130 &
120 ^
110 |
100 &&
 90 ||
 80 ??
 70 ? :
 60 = += -= *= **= /= .= %= &= |= ^= <<= >>=
 50 yield from
 40 yield
 30 and
 20 xor
 10 or

* Added if() function

* Cache key fix

There are cases where the cache key creation raised an error, for example
while evaluating the expression "if(cos(2), cos(2), 0)", because the
if() function was passing a float to the MathExecutor:execute() method.

1 files changed, 53 insertions, 0 deletions

diff --git a/src/NXP/Classes/Token/TokenGreaterThan.php b/src/NXP/Classes/Token/TokenGreaterThan.php
new file mode 100644
index 0000000..51a5aca
--- /dev/null
+++ b/src/NXP/Classes/Token/TokenGreaterThan.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace NXP\Classes\Token;
+
+use NXP\Exception\IncorrectExpressionException;
+
+class TokenGreaterThan extends AbstractOperator
+{
+    /**
+     * @return string
+     */
+    public static function getRegex()
+    {
+        return '>';
+    }
+
+    /**
+     * @return int
+     */
+    public function getPriority()
+    {
+        return 150;
+    }
+
+    /**
+     * @return string
+     */
+    public function getAssociation()
+    {
+        return self::LEFT_ASSOC;
+    }
+
+    /**
+     * @param InterfaceToken[] $stack
+     *
+     * @return $this
+     *
+     * @throws \NXP\Exception\IncorrectExpressionException
+     */
+    public function execute(&$stack)
+    {
+        $op2 = array_pop($stack);
+        $op1 = array_pop($stack);
+
+        if ($op1 === null || $op2 === null) {
+            throw new IncorrectExpressionException("> requires two operators");
+        }
+
+        $result = $op1->getValue() > $op2->getValue();
+
+        return new TokenNumber($result);
+    }
+}