Added ability to escape quotes in strings. (#110)

* Added ability to escape quotes in strings.

* Removed type checking for customfunc arguments. It was a bad idea to check types, because php automatically tries to convert a parameter to required type and throws if it failures. On the other hand, we can check types also in callables if required.

* Update phpdoc

* Fix some typos + improve min, max, avg funcs.

* Update readme + improvements.

* Fix a typo in sample.

* Fix unshown backslash in readme.

3 files changed, 68 insertions, 40 deletions

diff --git a/src/NXP/Classes/CustomFunction.php b/src/NXP/Classes/CustomFunction.php
index 1ebdd2c..6e9ffc5 100644
--- a/src/NXP/Classes/CustomFunction.php
+++ b/src/NXP/Classes/CustomFunction.php
@@ -2,7 +2,6 @@
 
 namespace NXP\Classes;
 
-use NXP\Exception\IncorrectFunctionParameterException;
 use NXP\Exception\IncorrectNumberOfFunctionParametersException;
 use ReflectionException;
 use ReflectionFunction;
@@ -16,7 +15,7 @@ class CustomFunction
      */
     public $function;
 
-    private ReflectionFunction $reflectionFunction;
+    private int $requiredParamCount;
 
     /**
      * CustomFunction constructor.
@@ -27,36 +26,25 @@ class CustomFunction
     {
         $this->name = $name;
         $this->function = $function;
-        $this->reflectionFunction = new ReflectionFunction($function);
+        $this->requiredParamCount = (new ReflectionFunction($function))->getNumberOfRequiredParameters();
 
     }
 
     /**
      * @param array<Token> $stack
      *
-     * @throws IncorrectNumberOfFunctionParametersException|IncorrectFunctionParameterException
+     * @throws IncorrectNumberOfFunctionParametersException
      */
     public function execute(array &$stack, int $paramCountInStack) : Token
     {
-        if ($paramCountInStack < $this->reflectionFunction->getNumberOfRequiredParameters()) {
+        if ($paramCountInStack < $this->requiredParamCount) {
             throw new IncorrectNumberOfFunctionParametersException($this->name);
         }
         $args = [];
 
         if ($paramCountInStack > 0) {
-            $reflectionParameters = $this->reflectionFunction->getParameters();
-
             for ($i = 0; $i < $paramCountInStack; $i++) {
-                $value = \array_pop($stack)->value;
-                $valueType = \gettype($value);
-                $reflectionParameter = $reflectionParameters[\min(\count($reflectionParameters) - 1, $i)];
-                //TODO to support type check for union types (php >= 8.0) and intersection types (php >= 8.1), we should increase min php level in composer.json
-                // For now, only support basic types. @see testFunctionParameterTypes
-                if ($reflectionParameter->hasType() && $reflectionParameter->getType()->getName() !== $valueType){
-                    throw new IncorrectFunctionParameterException();
-                }
-
-                \array_unshift($args, $value);
+                \array_unshift($args, \array_pop($stack)->value);
             }
         }
 
diff --git a/src/NXP/Classes/Tokenizer.php b/src/NXP/Classes/Tokenizer.php
index c8b415d..af041c1 100644
--- a/src/NXP/Classes/Tokenizer.php
+++ b/src/NXP/Classes/Tokenizer.php
@@ -50,27 +50,67 @@ class Tokenizer
 
     public function tokenize() : self
     {
-        foreach (\str_split($this->input, 1) as $ch) {
+        $isLastCharEscape = false;
+
+        foreach (\str_split($this->input) as $ch) {
             switch (true) {
                 case $this->inSingleQuotedString:
-                    if ("'" === $ch) {
-                        $this->tokens[] = new Token(Token::String, $this->stringBuffer);
-                        $this->inSingleQuotedString = false;
-                        $this->stringBuffer = '';
+                    if ('\\' === $ch) {
+                        if ($isLastCharEscape) {
+                            $this->stringBuffer .= '\\';
+                            $isLastCharEscape = false;
+                        } else {
+                            $isLastCharEscape = true;
+                        }
+
+                        continue 2;
+                    } elseif ("'" === $ch) {
+                        if ($isLastCharEscape) {
+                            $this->stringBuffer .= "'";
+                            $isLastCharEscape = false;
+                        } else {
+                            $this->tokens[] = new Token(Token::String, $this->stringBuffer);
+                            $this->inSingleQuotedString = false;
+                            $this->stringBuffer = '';
+                        }
 
                         continue 2;
                     }
+
+                    if ($isLastCharEscape) {
+                        $this->stringBuffer .= '\\';
+                        $isLastCharEscape = false;
+                    }
                     $this->stringBuffer .= $ch;
 
                     continue 2;
 
                 case $this->inDoubleQuotedString:
-                    if ('"' === $ch) {
-                        $this->tokens[] = new Token(Token::String, $this->stringBuffer);
-                        $this->inDoubleQuotedString = false;
-                        $this->stringBuffer = '';
+                    if ('\\' === $ch) {
+                        if ($isLastCharEscape) {
+                            $this->stringBuffer .= '\\';
+                            $isLastCharEscape = false;
+                        } else {
+                            $isLastCharEscape = true;
+                        }
 
                         continue 2;
+                    } elseif ('"' === $ch) {
+                        if ($isLastCharEscape) {
+                            $this->stringBuffer .= '"';
+                            $isLastCharEscape = false;
+                        } else {
+                            $this->tokens[] = new Token(Token::String, $this->stringBuffer);
+                            $this->inDoubleQuotedString = false;
+                            $this->stringBuffer = '';
+                        }
+
+                        continue 2;
+                    }
+
+                    if ($isLastCharEscape) {
+                        $this->stringBuffer .= '\\';
+                        $isLastCharEscape = false;
                     }
                     $this->stringBuffer .= $ch;
 
diff --git a/src/NXP/MathExecutor.php b/src/NXP/MathExecutor.php
index dd90e22..1e1cd2d 100644
--- a/src/NXP/MathExecutor.php
+++ b/src/NXP/MathExecutor.php
@@ -16,7 +16,6 @@ use NXP\Classes\Operator;
 use NXP\Classes\Token;
 use NXP\Classes\Tokenizer;
 use NXP\Exception\DivisionByZeroException;
-use NXP\Exception\IncorrectNumberOfFunctionParametersException;
 use NXP\Exception\MathExecutorException;
 use NXP\Exception\UnknownVariableException;
 use ReflectionException;
@@ -386,19 +385,21 @@ class MathExecutor
           'arccos' => static fn($arg) => \acos($arg),
           'arctan' => static fn($arg) => \atan($arg),
           'arctg' => static fn($arg) => \atan($arg),
+          'array' => static fn(...$args) => $args,
           'asin' => static fn($arg) => \asin($arg),
           'atan' => static fn($arg) => \atan($arg),
           'atan2' => static fn($arg1, $arg2) => \atan2($arg1, $arg2),
           'atanh' => static fn($arg) => \atanh($arg),
           'atn' => static fn($arg) => \atan($arg),
-          'avg' => static function($arg1, $args) {
+          'avg' => static function($arg1, ...$args) {
               if (\is_array($arg1)){
+                  if (0 === \count($arg1)){
+                      throw new \InvalidArgumentException('Array must contain at least one element!');
+                  }
+
                   return \array_sum($arg1) / \count($arg1);
               }
 
-              if (0 === \count($args)){
-                  throw new IncorrectNumberOfFunctionParametersException();
-              }
               $args = [$arg1, ...$args];
 
               return \array_sum($args) / \count($args);
@@ -444,18 +445,18 @@ class MathExecutor
           'log10' => static fn($arg) => \log10($arg),
           'log1p' => static fn($arg) => \log1p($arg),
           'max' => static function($arg1, ...$args) {
-              if (! \is_array($arg1) && 0 === \count($args)){
-                  throw new IncorrectNumberOfFunctionParametersException();
+              if (\is_array($arg1) && 0 === \count($arg1)){
+                      throw new \InvalidArgumentException('Array must contain at least one element!');
               }
 
-              return \max($arg1, ...$args);
+              return \max(\is_array($arg1) ? $arg1 : [$arg1, ...$args]);
           },
           'min' => static function($arg1, ...$args) {
-              if (! \is_array($arg1) && 0 === \count($args)){
-                  throw new IncorrectNumberOfFunctionParametersException();
+              if (\is_array($arg1) && 0 === \count($arg1)){
+                  throw new \InvalidArgumentException('Array must contain at least one element!');
               }
 
-              return \min($arg1, ...$args);
+              return \min(\is_array($arg1) ? $arg1 : [$arg1, ...$args]);
           },
           'octdec' => static fn($arg) => \octdec($arg),
           'pi' => static fn() => M_PI,
@@ -469,8 +470,7 @@ class MathExecutor
           'tan' => static fn($arg) => \tan($arg),
           'tanh' => static fn($arg) => \tanh($arg),
           'tn' => static fn($arg) => \tan($arg),
-          'tg' => static fn($arg) => \tan($arg),
-          'array' => static fn(...$args) => [...$args]
+          'tg' => static fn($arg) => \tan($arg)
         ];
     }
 
@@ -488,7 +488,7 @@ class MathExecutor
     }
 
     /**
-     * Default variable validation, ensures that the value is a scalar.
+     * Default variable validation, ensures that the value is a scalar or array.
      * @throws MathExecutorException if the value is not a scalar
      */
     protected function defaultVarValidation(string $variable, $value) : void