1 files changed, 86 insertions, 12 deletions

diff --git a/src/Interpreter/Interpreter.php b/src/Interpreter/Interpreter.php
index e8b3c82..eed0004 100644
--- a/src/Interpreter/Interpreter.php
+++ b/src/Interpreter/Interpreter.php
@@ -28,6 +28,7 @@ use Mnml\Parser\Parenthesis;
 use Mnml\Parser\Parser;
 use Mnml\Parser\PipeExpression;
 use Mnml\Parser\StringNode;
+use Mnml\Parser\VariableAssignment;
 
 class Interpreter
 {
@@ -62,12 +63,46 @@ class Interpreter
     {
         if ($currentNode instanceof ConstVariableDeclaration) {
             $identifier = $currentNode->identifier;
-            $value = $this->evaluate($currentNode->expression, $scope);
-            $scope->add($identifier, $value);
+            $value = new ValueNode(null);
+
+            /*if ($scope->has($identifier)) {
+                echo sprintf("%s already declared in current scope." . PHP_EOL, $identifier->token->value);
+            }*/ # TODO: problems with recursive functions. clear scope somehow?
+
+            #else {
+                if (! is_null($currentNode->expression)) {
+                    $value = $this->evaluate($currentNode->expression, $scope);
+                }
+
+                $scope->add($identifier, $value);
+            #}
 
             return $value;
         }
 
+        if ($currentNode instanceof VariableAssignment) {
+            $identifier = $currentNode->identifier;
+            $value = new ValueNode(null);
+            
+            if ($scope->has($identifier)) {
+                $curentValue = $scope->get($identifier)->getValue();
+                
+                if (is_null($curentValue)) {
+                    $value = $this->evaluate($currentNode->expression, $scope);
+                    $scope->set($identifier, $value);
+                }
+                else {
+                    echo sprintf("%s already assigned in current scope." . PHP_EOL, $identifier->token->value);
+                }
+            }
+            
+            else {
+                 echo sprintf("%s is not declared in current scope." . PHP_EOL, $identifier->token->value);                           
+            }
+
+            return $value;            
+        }
+        
         else if ($currentNode instanceof IdentifierNode) {
             $variable = $scope->get($currentNode);
 
@@ -181,10 +216,10 @@ class Interpreter
             $functionDefinition = $scope->get($currentNode->identifier);
 
             if ($functionDefinition instanceof FunctionDefinition) {
-                return $this->evaluateFunction($functionDefinition, $currentNode->parameters, $scope);
+                return $this->evaluateFunction($currentNode->identifier, $functionDefinition, $currentNode->parameters, $scope);
             }
             else if ($functionDefinition instanceof Closure) {
-                return $this->evaluateClosure($functionDefinition, $currentNode->parameters, $scope);
+                return $this->evaluateClosure($currentNode->identifier, $functionDefinition, $currentNode->parameters, $scope);
             }
 
             return $currentNode;
@@ -263,6 +298,9 @@ class Interpreter
                     }
                 }
             }
+            else if ($accessee instanceof ValueNode) {
+                $accessee = new ValueNode($accessee->getValue()[$evaluation]);
+            }
         }
 
         return $accessee;
@@ -271,15 +309,15 @@ class Interpreter
     /**
     * @param FunctionCallParameter[] $parameters
     */
-    private function evaluateFunction(FunctionDefinition $function, array $parameters, Scope $outerScope): mixed
+    private function evaluateFunction(IdentifierNode $identifier, FunctionDefinition $function, array $parameters, Scope $outerScope): mixed
     {
         $scope = new Scope($outerScope);
 
         foreach ($parameters as $parameter) {
             /**@var FunctionCallParameter $parameter*/
-            $scope->add($parameter->identifier, $parameter->value);
+            $scope->add($parameter->identifier, $this->evaluate($parameter->value, $outerScope));
         }
-        
+
         foreach ($function->body as $currentNode) {
             if ($currentNode instanceof FunctionReturn) {
                 return $this->evaluate($currentNode->returnValue, $scope);
@@ -299,21 +337,21 @@ class Interpreter
             }
         }
 
-        echo sprintf("Function %s missing return value." . PHP_EOL);
+        echo sprintf("Function %s missing return value." . PHP_EOL, $identifier->token->value);
     }
 
     /**
     * @param FunctionCallParameter[] $parameters
     */
-    private function evaluateClosure(Closure $function, array $parameters, Scope $scope): mixed
+    private function evaluateClosure(IdentifierNode $identifier, Closure $function, array $parameters, Scope $scope): mixed
     {
         $evaluatedParameters = [];
         foreach ($parameters as $parameter) {
             /**@var FunctionCallParameter $parameter*/
             $evaluatedParameters[] = $this->evaluate($parameter->value, $scope)->getValue();
         }
-        
-        return call_user_func_array($function, $evaluatedParameters);
+
+        return new ValueNode(call_user_func_array($function, $evaluatedParameters));
     }
 
     private function evaluateIfArmBody(IfArm $arm, Scope $outerScope): mixed
@@ -356,7 +394,11 @@ class Scope
         $key = $identifier->token->value;
         
         if (isset($this->values[$key])) {
-            return $this->values[$key];
+            $value = $this->values[$key];
+            if ($value instanceof IdentifierNode and $value->token->value == $key) {}
+            else {
+                return $this->values[$key];
+            }
         }
 
         if (! isset($this->outerScope)) {
@@ -368,6 +410,38 @@ class Scope
         return $this->outerScope->get($identifier);
     }
 
+    public function set(IdentifierNode $identifier, mixed $value): void
+    {
+        $key = $identifier->token->value;
+
+        if (isset($this->values[$key])) {
+            $this->values[$key] = $value;
+        }
+
+        else if (isset($this->outerScope)){
+            $this->outerScope->set($identifier, $value);
+        }
+
+        else {
+            echo sprintf("Can't set nonexistent variable %s." . PHP_EOL, $identifier->token->value);            
+        }
+    }
+
+    public function has(IdentifierNode $identifier): bool
+    {
+        $has = isset($this->values[$identifier->token->value]);
+
+        if ($has) {
+            return $has;
+        }
+
+        if (isset($this->outerScope)) {
+            return $this->outerScope->has($identifier);
+        }
+
+        return false;
+    }
+
     public function addExternal(string $identifier, mixed $value): void
     {
         $this->values[$identifier] = $value;