add showSqlTypeWithSchema for types in a schema

[stevemao]

• similar to enumMapperWithSchema
• enums needs an instance of IsSqlType if used with an array
• enums can have a schema

[tomjaguarpaw]

If you want a schema I don't understand why you can't just do showSqlType = "\"foo\".\"bar\"".

[stevemao]

I can, but other APIs such as enumMapperWithSchema has a spot for schema. This is to make it consistent with these APIs.

[tomjaguarpaw]

I see. Then in that case I think showSqlTypeWithSchema wants just to be a function

showSqlTypeWithSchema :: (String, String) -> String
showSqlTypeWithSchema (schema, type_) =
  render (doubleQuotes (text schema) <> text "." <> doubleQuotes (text type_))

that you use like

instance IsSqlType Whatever where
  showSqlType = showSqlTypeWithSchema ("schema", "type_name")

Making it a class method means that all instances have to implement it, which is not what we want because not all type names have a schema.

[stevemao]

Happy with a function to make it simple. But I have some questions

showSqlTypeWithSchema seems to be quite generic. Maybe we can call it sqlTypeWithSchema?

Making it a class method means that all instances have to implement it, which is not what we want because not all type names have a schema.

Not really? the instance can choose to implement either method {-# MINIMAL showSqlType | showSqlTypeWithSchema #-}

[tomjaguarpaw]

Making it a class method means that all instances have to implement it, which is not what we want because not all type names have a schema.

Not really? the instance can choose to implement either method {-# MINIMAL showSqlType | showSqlTypeWithSchema #-}

But what if an instance choose not to implement it but then a user calls it on that instance? Run time crash, presumably.

[stevemao]

Ok, definitely not ideal even though it's an internal module

[tomjaguarpaw]

Thanks, I tweaked this and merged it in f012b27

[tomjaguarpaw]

Released as https://hackage.haskell.org/package/opaleye-0.10.3.0