Fold direction note

ideas.md

@@ -86,6 +86,7 @@ Lists, Sets, Vectors, Arrays etc. all need simple literal syntaxes.
 
 - ~~Mainly lazy or~~ mainly strict? (→ Haskell/Idris)
   - Probably mainly strict with explicit laziness possible (like in Idris) because of performance and algebraic typing
+  - Strict evaluation -> foldr of expression tree
 - Totality enforced by default (no `fromJust`, `error` etc.)?
     - Do the pros outweigh the cons here?
     - Not decidable in general, so it's a burden on the user if the totality checking fails