Add a note

schala-lang/src/reduced_ast.rs

@@ -221,6 +221,9 @@ impl Pattern {
         unimplemented!()
       },
       Ignored => unimplemented!(),
+      /* "a constant appearing in a pattern can easily be eliminated by replacing it with a variable
+       * and adding a guard to the equation instead" -  Implementation of Functional Programming
+       * Languages Simon Peyton-Jones, p. 58 */
       Literal(lit) => match lit {
         PatternLiteral::NumPattern { neg, num } => unimplemented!(),
         PatternLiteral::StringPattern(_s) => unimplemented!(),