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syntaxrecordcapitalizationpurescript

Can records have capitalized fields?

In purescript, {foo :: Foo} desugars to Record ("foo" :: Foo), as far as my understanding goes. Could I make something like Record ("F" :: Foo)? How would that look in record access syntax? Would thing.F be syntactically valid?

Solution

  • Quoting fields is exactly the way to do it, both in the type:

    type MyRecord = { "Usually impossible field name" :: Boolean }

    And in accessors / patterns:

    make :: Boolean -> MyRecord
make = { "Usually impossible field name": _ }

get :: MyRecord -> Boolean
get = _."Usually impossible field name"

update :: MyRecord -> Boolean -> MyRecord
update = _ { "Usually impossible field name" = _ }

    Quoting fields this way allows you to name the record fields whatever you want, using caps, symbols, numbers, etc.

    This is a little similar to obj["property"] in JavaScript, but you can only use string literals for the property name rather than arbitrary values.