Feat: Add Character, String and float literals

test/ressources/test.🥐

@@ -1,33 +1 @@
-1 + 1;
-4 * 0;
-
-/*
-
-Root(
-  SequenceStatement(
-    ExpressionStatement(
-      BinaryExpression(
-        Add,
-        Literal(
-          Integer(1)
-        ),
-        Literal(
-          Integer(1)
-        )
-      )
-    ),
-    ExpressionStatement(
-      BinaryExpression(
-        Multiply,
-        Literal(
-          Integer(4)
-        ),
-        Literal(
-          Integer(0)
-        )
-      )
-    )
-  )
-)
-
-*/
+'a';

test/syntax/TestExpressions.ml

@@ -7,6 +7,9 @@ let test_pp_expressions () =
       ( "Should return \"Literal(...)\"",
         "Literal(Integer(1))",
         Expressions.Literal (Literals.Integer 1) );
+      ( "Should return \"Identifier(...)\"",
+        "Identifier(\"myVar\")",
+        Expressions.Identifier "myVar" );
       ( "Should return \"UnaryExpression(...)\"",
         "UnaryExpression(ArithmeticNegation, Literal(Integer(2)))",
         Expressions.UnaryExpression