diff --git a/.gitignore b/.gitignore
index 56bcbd6..3a55b65 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,6 @@
+.idea
+
 prompt.sh
-prompt.txt
\ No newline at end of file
+prompt.txt
+compile_grammar.sh
+waddle.bnf
diff --git a/README.md b/README.md
index f760e9d..c7a93ae 100644
--- a/README.md
+++ b/README.md
@@ -208,6 +208,41 @@ if(my.age.gt(18).and(my.status.is(Verified))){
 }
 ```
 
+#### If conditionals
+##### Plain If
+```waddle
+if (x.gt(0).and(y.gt(0))) {
+    rtn True;
+}
+```
+##### If/Otherwise
+```waddle
+if (x.gt(0).and(y.gt(0))) {
+    rtn True;
+} otherwise {
+    rtn False;
+}
+```
+##### If/Orif
+```waddle
+if (x.gt(0).and(y.gt(0))) {
+    rtn True;
+} orif (x.lt(0).and(y.lt(0))) {
+    rtn False;
+}
+```
+##### If/Orif/Otherwise
+```waddle
+if (x.gt(0).and(y.gt(0))) {
+    rtn True;
+} orif (x.lt(0).and(y.lt(0))) {
+    rtn False;
+} otherwise {
+    rtn False;
+}
+```
+
+
 ### Explicit Type Conversion
 ```waddle
 String myString.set(my.number.set(42).as(String));
diff --git a/grammar/core/literals.bnf b/grammar/core/literals.bnf
index 2e4bec1..02156a5 100644
--- a/grammar/core/literals.bnf
+++ b/grammar/core/literals.bnf
@@ -12,7 +12,7 @@
 <decimal_literal> ::= <digit>+ "." <digit>+
                     | "-" <digit>+ "." <digit>+
 
-<string_literal> ::= '"' [^"]* '"'
+<string_literal> ::= '"' [^\"]* '"'
                    | "'" [^']* "'"
 
 <boolean_literal> ::= "True" | "False"
diff --git a/grammar/core/modules.bnf b/grammar/core/modules.bnf
deleted file mode 100644
index 3bf83cf..0000000
--- a/grammar/core/modules.bnf
+++ /dev/null
@@ -1,16 +0,0 @@
-<module_declaration> ::= "module" <identifier> "{" 
-    (<export_declaration> 
-    | <constant_declaration>
-    | <declaration>)* 
-"}"
-
-<export_declaration> ::= 
-    <accessibility_modifier>"export" 
-    (<constant_declaration>
-    | <type_declaration> 
-    | <function_declaration>)
-
-<visibility_rule> ::= 
-    <accessibility_modifier> 
-    (<type_declaration> 
-    | <function_declaration>)
\ No newline at end of file
diff --git a/grammar/core/visibility.bnf b/grammar/core/visibility.bnf
index a089d7d..e03c6f6 100644
--- a/grammar/core/visibility.bnf
+++ b/grammar/core/visibility.bnf
@@ -2,4 +2,3 @@
     "-"
     | ""
     | "+"
-    | "export"
diff --git a/grammar/declarations/error_declarations.bnf b/grammar/declarations/error_declarations.bnf
index c71b2e8..9a6a145 100644
--- a/grammar/declarations/error_declarations.bnf
+++ b/grammar/declarations/error_declarations.bnf
@@ -1,7 +1,13 @@
-<error_declaration> ::= <identifier> 
-    ["/" <identifier>]? 
+<error_declaration> ::= <inherited_error_type>
     "{" <error_body>? "}"
 
+<inherited_error_type> ::= [<parent_error> "/"]? <child_error>
+
+<parent_error> ::= <identifier>
+
+<child_error> ::= <identifier>
+
 <error_body> ::= (<variable_declaration> 
                 | <constant_declaration>
                 | <function_declaration>)*
+
diff --git a/grammar/declarations/function_declarations.bnf b/grammar/declarations/function_declarations.bnf
index e68ac48..6312dce 100644
--- a/grammar/declarations/function_declarations.bnf
+++ b/grammar/declarations/function_declarations.bnf
@@ -10,13 +10,25 @@
 
 <error_type> ::= <identifier> ["/" <identifier>]?
 
-<parameter_list> ::= <required_parameter> 
-    ("," <required_parameter>)* 
-    [("," <default_parameter>)*]
+<parameter_list> ::=
+    <parameter_group>?
 
-<required_parameter> ::= <identifier> ":" <parameter_type>
+<parameter_group> ::=
+    <required_parameters>
+    | <required_parameters> "," <default_parameters>
+    | <default_parameters>
 
-<default_parameter> ::= <identifier> ".default(" <literal> ")"
+<required_parameters> ::=
+    <required_parameter>
+    | <required_parameter> "," <required_parameters>
+
+<default_parameters> ::=
+    <default_parameter>
+    | <default_parameter> "," <default_parameters>
+
+<required_parameter> ::= <parameter_type> <identifier>
+
+<default_parameter> ::= <parameter_type> <identifier> ".default(" <literal> ")"
 
 <lambda_declaration> ::= "fn" "(" <parameter_list>? ")" 
     "->" "[" <type> "]" 
diff --git a/grammar/declarations/object_instantiation.bnf b/grammar/declarations/object_instantiation.bnf
deleted file mode 100644
index c435f7b..0000000
--- a/grammar/declarations/object_instantiation.bnf
+++ /dev/null
@@ -1,3 +0,0 @@
-<object_instantiation> ::= "new" <type> "(" <argument_list>? ")"
-
-<type> ::= <identifier> ["/" <identifier>]?
diff --git a/grammar/declarations/type_declarations.bnf b/grammar/declarations/type_declarations.bnf
index 49a9d81..9ac24b1 100644
--- a/grammar/declarations/type_declarations.bnf
+++ b/grammar/declarations/type_declarations.bnf
@@ -1,5 +1,5 @@
 <type_declaration> ::= <inherited_type> 
-    ["->" <interface_identifier_list>]? 
+    <interface_implementation>?
     "{" <class_body> "}"
 
 <class_body> ::= (<variable_declaration> 
@@ -20,3 +20,14 @@
     [".set(" <expression> ")"]? ";"
 
 <constant_declaration> ::= <type> <identifier> ".define(" <literal> ");"
+
+<constructor_declaration> ::=
+    <accessibility_modifier> "on_create" "(" <parameter_list>? ")"
+    ["fails" "with" <error_type_list>]?
+    "{" <statement>* "}"
+
+<destructor_declaration> ::=
+    <accessibility_modifier> "on_destroy" "(" <parameter_list>? ")"
+    ["fails" "with" <error_type_list>]?
+    "{" <statement>* "}"
+
diff --git a/grammar/interfaces/interface_definitions.bnf b/grammar/interfaces/interface_definitions.bnf
index 884c607..5f8163d 100644
--- a/grammar/interfaces/interface_definitions.bnf
+++ b/grammar/interfaces/interface_definitions.bnf
@@ -1,17 +1,16 @@
-<interface_declaration> ::= "@" <interface_identifier> "{" <interface_body> "}"
+<interface_declaration> ::= "@" [<interface_parent> "/"]? <interface_child>
+                                "{" <interface_body> "}"
 
-<interface_identifier> ::= <identifier>
+<interface_parent> ::= <identifier>
+
+<interface_child> ::= <identifier>
 
 <interface_body> ::= <interface_method_declaration>*
 
 <interface_method_declaration> ::= 
     <accessibility_modifier> "fn" <identifier> <function_signature> ";"
 
-<interface_implementation> ::= <type_declaration> "->" <interface_identifier_list>
+<interface_implementation> ::= "->" <interface_identifier_list>
 
 <interface_method_signature> ::= 
     <accessibility_modifier>"fn" <identifier> <function_signature>
-
-<interface_inheritance> ::= 
-    "@" <interface_identifier> "extends" <interface_identifier_list> 
-    "{" <interface_body> "}"
diff --git a/grammar/main.bnf b/grammar/main.bnf
index 3e916d1..c243549 100644
--- a/grammar/main.bnf
+++ b/grammar/main.bnf
@@ -1,24 +1,20 @@
-<program> ::= <module_declaration>* <use_statement>* <declaration>*
-
-<module_declaration> ::= "module" <identifier> "{" 
-    (<export_declaration> | <declaration>)* 
-"}"
-
-<export_declaration> ::= <accessibility_modifier>"export" 
-    (<type_declaration> | <function_declaration>)
+<program> ::= <use_statement>* <top_level_definition>*
 
 <use_statement> ::= "use" <identifier> ("." <identifier>)* ";"
 
+<top_level_definition> ::=
+    <type_declaration>
+    | <interface_declaration>
+    | <error_declaration>
+
 import "core/base_types.bnf"
 import "core/identifiers.bnf"
 import "core/literals.bnf"
 import "core/visibility.bnf"
-import "core/modules.bnf"
+import "declarations/error_declarations.bnf"
 import "declarations/type_declarations.bnf"
 import "declarations/function_declarations.bnf"
-import "declarations/object_instantiation.bnf"
 import "operations/expressions.bnf"
 import "operations/method_calls.bnf"
 import "operations/control_flow.bnf"
 import "interfaces/interface_definitions.bnf"
-import "modules/**/*.bnf"
diff --git a/grammar/modules/core/directory.wdl b/grammar/modules/core/directory.wdl
index 6f1a38f..64c5885 100644
--- a/grammar/modules/core/directory.wdl
+++ b/grammar/modules/core/directory.wdl
@@ -2,55 +2,6 @@ use core.accessibility_modifier;
 use core.identifier;
 use core.type_system;
 
-module Directory {
-    syntax {
-        type_system.extend({
-            name: "Directory",
-            category: "system_resource",
-            immutable_operations: true
-        });
-    }
-
-    // Directory permissions enum
-    type DirectoryPermission {
-        String read = "r";
-        String write = "w";
-        String execute = "x";
-    }
-
-    // Core Directory type
-    type Directory {
-        String path;
-        Integer item_count;
-        
-        +fn on_create(String dirpath) -> [Directory];
-        
-        +fn list_contents() -> [String<>];
-        +fn create() -> [Boolean];
-        
-        +fn exists() -> [Boolean];
-        +fn delete() -> [Boolean];
-        +fn move(String destination) -> [Boolean];
-        +fn copy(String destination) -> [Boolean];
-        
-        +fn get_permissions() -> [DirectoryPermission<>];
-        +fn set_permissions(DirectoryPermission<> permissions) -> [Boolean];
-    }
-
-    // Directory operations
-    +fn create(String path) -> [Directory];
-    +fn exists(String path) -> [Boolean];
-    +fn delete(String path) -> [Boolean];
-    +fn move(String source, String destination) -> [Boolean];
-    +fn copy(String source, String destination) -> [Boolean];
-    +fn list_contents(String path) -> [String<>];
-}
-
-
-
-
-
-
 module Directory {
     // Language extension configuration
     syntax {
diff --git a/grammar/operations/control_flow.bnf b/grammar/operations/control_flow.bnf
index a4f97ac..32f073e 100644
--- a/grammar/operations/control_flow.bnf
+++ b/grammar/operations/control_flow.bnf
@@ -13,7 +13,8 @@
 
 <if_statement> ::= "if" "(" <boolean_expression> ")" 
     "{" <statement>* "}" 
-    ["else" "{" <statement>* "}"]?
+    ["orif" "(" <boolean_expression> ")" "{" <statement>* "}"]?
+    ["otherwise" "{" <statement>* "}"]?
 
 <while_statement> ::= "while" "(" <expression> ")" 
     "{" <statement>* "}"
diff --git a/grammar/operations/expressions.bnf b/grammar/operations/expressions.bnf
index 0c84e6c..7a82e23 100644
--- a/grammar/operations/expressions.bnf
+++ b/grammar/operations/expressions.bnf
@@ -1,34 +1,32 @@
 <expression> ::= <my_identifier>
                | <literal>
                | <object_method_call>
-               | <constant_expression>
-               | <object_instantiation>
+               | <constant_declaration>
                | <type_conversion_expression>
                | "(" <expression> ")"
-               | <lambda_expression>
+               | <lambda_declaration>
 
 <type_conversion_expression> ::= <my_identifier> ".as(" <type> ")"
 
 <boolean_expression> ::= 
     <boolean_literal>
     | "(" <boolean_expression> ")"
-    | <my_identifier>.eq(<expression>)
-    | <my_identifier>.is(<expression>)
-    | <my_identifier>.not(<expression>)
-    | <my_identifier>.gt(<expression>)
-    | <my_identifier>.lt(<expression>)
-    | <my_identifier>.gte(<expression>)
-    | <my_identifier>.lte(<expression>)
-    | <my_identifier>.and(<boolean_expression>)
-    | <my_identifier>.or(<boolean_expression>)
-    | Boolean.and(<boolean_expression>, <boolean_expression>)
-    | Boolean.or(<boolean_expression>, <boolean_expression>)
-    | Boolean.not(<boolean_expression>)
-    | Boolean.eq(<boolean_expression>, <boolean_expression>)
-    | Boolean.is(<boolean_expression>, <boolean_expression>)
-    | Boolean.gt(<boolean_expression>, <boolean_expression>)
-    | Boolean.lt(<boolean_expression>, <boolean_expression>)
-    | Boolean.gte(<boolean_expression>, <boolean_expression>)
-    | Boolean.lte(<boolean_expression>, <boolean_expression>)
+    | <my_identifier> ".eq(" <expression> ")"
+    | <my_identifier> ".is(" <expression> ")"
+    | <my_identifier> ".not(" <expression> ")"
+    | <my_identifier> ".gt(" <expression> ")"
+    | <my_identifier> ".lt(" <expression> ")"
+    | <my_identifier> ".gte(" <expression> ")"
+    | <my_identifier> ".lte(" <expression> ")"
+    | <my_identifier> ".and(" <boolean_expression> ")"
+    | <my_identifier> ".or(" <boolean_expression> ")"
+    | "Boolean.and(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.or(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.not(" <boolean_expression> ")"
+    | "Boolean.eq(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.is(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.gt(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.lt(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.gte(" <boolean_expression> "," <boolean_expression> ")"
+    | "Boolean.lte(" <boolean_expression> "," <boolean_expression> ")"
 
-<constant_expression> ::= <my_identifier> ".define(" <literal> ")"
\ No newline at end of file