basic interpreter functionality

johncameronthomas · Apr 14, 2023 · d2c4ec1 · d2c4ec1
1 parent 55aa019
commit d2c4ec1
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Showing 4 changed files with 65 additions and 24 deletions.
diff --git a/scribe/Context.py b/scribe/Context.py
@@ -1,3 +1,5 @@
+from Error import Runtime_Error
+
 class Context:
     def __init__(self, name, parent):
         self.name = name
@@ -10,13 +12,32 @@ def __repr__(self):
         else:
             return '{} -> {}'.format(self.parent, self.name)
 
-    def get(self, name):
-        value = self.symbol_table.get(name, None)
-        if value == None and self.parent:
-            return self.parent.get(name)
+    def define_symbol(self, identifier: str) -> bool:
+        if identifier in self.symbol_table.keys():
+            raise ValueError()
+        else:
+            self.symbol_table[identifier] = None
+
+    def delete_symbol(self, identifier: str) -> bool:
+        if identifier in self.symbol_table:
+            del self.symbol_table[identifier]
+        else:
+            raise ValueError()
+
+    def get_symbol(self, identifier: str):
+        if identifier not in self.symbol_table:
+            if self.parent != None:
+                return self.parent.get_symbol(identifier)
+            else:
+                raise ValueError()
+        else:
+            return self.symbol_table[identifier]
+
+    def set_symbol(self, identifier: str, data):
+        if identifier not in self.symbol_table:
+            if self.parent != None:
+                return self.parent.set_symbol(identifier, data)
+            else:
+                raise ValueError()
         else:
-            return value
-
-    def set(self, name, value):
-        self.symbol_table.update({name: value})
-        return value
+            self.symbol_table[identifier] = data
diff --git a/scribe/Interpreter.py b/scribe/Interpreter.py
@@ -1,9 +1,12 @@
-import Error
+from Error import Runtime_Error
+from Context import Context
+from Node import Data_Node
 
 class Interpreter:
     def __init__(self, node, context):
         self.node = node
         self.context = context
+
         self.error = None
 
     def interpret(self):
@@ -12,16 +15,25 @@ def interpret(self):
     def evaluate_node(self, node):
         match node.name:
             case 'Integer':
-                return node.value
-            case 'Float':
-                return node.value
-            case 'Variable Assignment':
-                return self.context.set(node.middle_child.value, self.evaluate_node(node.right_child))
-            case 'Indentifier':
-                result = self.context.get(node.value)
-                if result == None:
-                    self.error = Error.Runtime_Error('Undefined Variable', "'{}' is undefined.".format(node.value), node.location, self.context)
-                    return 0
+                return node.data
+            case 'Rational':
+                return node.data
+            case 'Symbol Assignment':
+                try:
+                    return self.context.set_symbol(self.evaluate_node(node.left_child).data, self.evaluate_node(node.right_child))
+                except:
+                    self.error = Runtime_Error('Symbol Not Defined', node.left_child, node.location, self.context)
+            case 'Symbol Definition':
+                try:
+                    self.context.define_symbol(node.child.data)
+                    return Data_Node('Identifier', node.child.data, node.location)
+                except:
+                    self.error = Runtime_Error('Symbol Already Defined', node.child.data, node.location, self.context)
+            case 'Identifier':
+                try:
+                    result = self.context.get_symbol(node.data)
+                except:
+                    self.error = Runtime_Error('Undefined Variable', node.data, node.location, self.context)
                 else:
                     return result
             case 'Subtraction':
@@ -32,7 +44,7 @@ def evaluate_node(self, node):
                 try:
                     return self.evaluate_node(node.left_child) / self.evaluate_node(node.right_child)
                 except:
-                    self.error = Error.Runtime_Error('Division by Zero', '', node.location, self.context)
+                    self.error = Runtime_Error('Division by Zero', '', node.location, self.context)
                     return 0
             case 'Multiplication':
                 return self.evaluate_node(node.left_child) * self.evaluate_node(node.right_child)
diff --git a/scribe/Parser.py b/scribe/Parser.py
@@ -24,7 +24,7 @@ def create_symbol_assignment_node(self):
             token = self.token
             self.advance()
             right_child = self.create_symbol_definition_node()
-            left_child = Binary_Operation_Node('Symbol Assignment Node', left_child, right_child, token.location)
+            left_child = Binary_Operation_Node('Symbol Assignment', left_child, right_child, token.location)
         return left_child
 
     def create_symbol_definition_node(self):

diff --git a/scribe/__main__.py b/scribe/__main__.py
@@ -16,12 +16,20 @@
         error.print_error(code)
         print()
         continue
+
     parser = Parser(tokens)
     tree, error = parser.parse()
     if error:
-        print(tree)
         print()
         error.print_error(code)
         print()
         continue
-    print(tree)
+
+    interpreter = Interpreter(tree, context)
+    result, error = interpreter.interpret()
+    if error:
+        print()
+        error.print_error(code)
+        print()
+        continue
+    print(result)