How to apply function lower_ to (Value (Maybe typ))?
I have maybe string field in db, so after (^.) operator I'll have expression with type: SqlExpr (Value (Maybe String)).
Let us suppose lower_ is SqlExpr (Value String) -> SqlExpr (Value String).
How to apply lower_ for this?
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Nick Mojarovskiy
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What should happen if the expression is `Nothing`? – Kwarrtz Sep 05 '15 at 01:49
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2`lower` has type `expr (Value a) -> expr (Value a)`. It should work fine on a `Value (Maybe typ)`. – Kwarrtz Sep 05 '15 at 02:07