feat: Implement function parameters and return values

examples/functions_with_params.fem

@@ -0,0 +1,12 @@
+Femboy add_numbers(a, b) Femboycore
+    Femme a + b
+Periodt
+
+result is add_numbers(10, 5)
+UwU Boy result
+
+Femboy greet(name) Femboycore
+    UwU Boy "Hello, " + name
+Periodt
+
+greet("World")

src/interpreter.py

@@ -1,9 +1,13 @@
 class Interpreter:
     def __init__(self, ast):
         self.ast = ast
-        self.variables = {}
+        self.scope_stack = [{}]
         self.functions = {}
 
+    @property
+    def current_scope(self):
+        return self.scope_stack[-1]
+
     def interpret(self):
         for node in self.ast:
             self.visit(node)
@@ -57,13 +61,14 @@ class Interpreter:
     def visit_Assign(self, node):
         var_name = node.left.value
         value = self.visit(node.right)
-        self.variables[var_name] = value
+        self.current_scope[var_name] = value
 
     def visit_Variable(self, node):
         var_name = node.value
-        if var_name in self.variables:
-            return self.variables[var_name]
-        else:
+        # Search up the scope stack for the variable
+        for scope in reversed(self.scope_stack):
+            if var_name in scope:
+                return scope[var_name]
         raise NameError(f"name '{var_name}' is not defined")
 
     def visit_Block(self, node):
@@ -93,14 +98,27 @@ class Interpreter:
             raise NameError(f"Function '{func_name}' is not defined")
 
         func_info = self.functions[func_name]
-        # For simplicity, no arguments are passed for now
-        # In a real interpreter, you'd push a new scope and bind arguments to parameters
+
+        # Evaluate arguments
+        evaluated_arguments = [self.visit(arg) for arg in node.arguments]
+
+        # Create a new scope for the function call
+        new_scope = {}
+        for i, param_name in enumerate(func_info['parameters']):
+            new_scope[param_name] = evaluated_arguments[i]
+
+        self.scope_stack.append(new_scope)
 
         # Execute function body
         try:
             self.visit(func_info['body'])
         except ReturnValue as e:
+            self.scope_stack.pop() # Pop the function scope
             return e.value
+        finally:
+            # Ensure scope is popped even if no return or an error occurs
+            if len(self.scope_stack) > 1: # Don't pop global scope
+                self.scope_stack.pop()
 
     def visit_ReturnStatement(self, node):
         raise ReturnValue(self.visit(node.value))

src/lexer.py

@@ -31,11 +31,13 @@ class Lexer:
 
         if current_char == '"':
             self.pos += 1
-            string_end = self.text.find('"', self.pos)
-            if string_end == -1:
-                self.error()
-            string = self.text[self.pos:string_end]
-            self.pos = string_end + 1
+            start_string = self.pos
+            while self.pos < len(self.text) and self.text[self.pos] != '"':
+                self.pos += 1
+            if self.pos == len(self.text):
+                self.error() # Unterminated string
+            string = self.text[start_string:self.pos]
+            self.pos += 1 # Consume closing quote
             return Token('STRING', string)
 
         if current_char.isdigit():
@@ -65,6 +67,9 @@ class Lexer:
         if current_char == '/':
             self.pos += 1
             return Token('DIV', '/')
+        if current_char == ',':
+            self.pos += 1
+            return Token('COMMA', ',')
         if current_char == '=':
             if self.pos + 1 < len(self.text) and self.text[self.pos + 1] == '=':
                 self.pos += 2

src/parser.py

@@ -196,8 +196,25 @@ class Parser:
         if name_token.type != 'ID':
             raise Exception("Expected function name (ID)")
         
-        # For simplicity, assume no parameters for now
+        print(f"After function name: {self.peek_next_token()}")
+
+        # Parse parameters
         parameters = []
+        if self.peek_next_token().type == 'LPAREN':
+            self.get_next_token() # Consume '('
+            print(f"After LPAREN: {self.peek_next_token()}")
+            while self.peek_next_token().type != 'RPAREN':
+                param_token = self.get_next_token()
+                if param_token.type != 'ID':
+                    raise Exception("Expected parameter name (ID)")
+                parameters.append(param_token.value)
+                print(f"After parameter {param_token.value}: {self.peek_next_token()}")
+                if self.peek_next_token().type == 'COMMA':
+                    self.get_next_token() # Consume ','
+                    print(f"After COMMA: {self.peek_next_token()}")
+                # No 'elif' here, the loop condition handles the RPAREN
+            self.get_next_token() # Consume ')'
+            print(f"After RPAREN: {self.peek_next_token()}")
 
         if self.peek_next_token().type != 'FEMBOYCORE':
             raise Exception("Expected 'Femboycore' to start function body")
@@ -258,9 +275,12 @@ class Parser:
     def parse_function_call(self, name_token):
         self.get_next_token() # Consume '('
         arguments = []
-        # For simplicity, assume no arguments for now
-        if self.peek_next_token().value == ')':
-            self.get_next_token() # Consume ')'
+        if self.peek_next_token().type != 'RPAREN':
+            while True:
+                arguments.append(self.expression())
+                if self.peek_next_token().type == 'COMMA':
+                    self.get_next_token() # Consume ','
                 else:
-            raise Exception("Expected ')' after function call")
+                    break # Exit loop if not COMMA (implies RPAREN or EOF)
+        self.get_next_token() # Consume ')'
         return FunctionCall(name_token.value, arguments)