feat: Add Literals and operator of comparison

lib/ast/syntax.ml

@@ -1,12 +1,34 @@
 (* lib/ast/syntax.ml *)
 
-type binary_operator = Add | Substract | Multiply | Divide
-type unary_operator = Negate
+type literal =
+  | Integer of int
+  | Float of float
+  | Character of char
+  | String of string
+  | Boolean of bool
+  | Null
+
+type binary_operator =
+  | Add
+  | Substract
+  | Multiply
+  | Divide
+  | AmpersandAmpersand
+  | BarBar
+  | EqualsEquals
+  | ExclamationEquals
+  | LessThan
+  | LessThanEquals
+  | GreaterThan
+  | GreaterThanEquals
+
+type unary_operator = Negate | Not
 
 type expression =
-  | IntegerLiteral of int
+  | Literal of literal
+  | Identifier of string
   | UnaryExpression of unary_operator * expression
   | BinaryExpression of binary_operator * expression * expression
 
 type statement = ExpressionStatement of expression
-type source_file = SourceFile of statement list
+type source_file = SourceFile of statement list