Hello everyone,

I have just started studying Haskell and I am having a hard time understanding type and value constructors.

So to create a new type, you write something like:

data FinancialInstrument = Financial  String Double

                                           deriving (Eq, Show)

and then you can write:

ibm = Financial "ibm" 150

OK all good. This initializes a FinancialInstrument. What I don't quite grasp is what is the purpose of Financial (the data/value constructor)? And from what I have read, you could have also written:

data FinancialInstrument = FinancialInstrument String Double

                                           deriving (Eq, Show)

To me the second expression is a lot closer to the typical OOP way of doing things (where the type name and constructor(s) have the same name). Why would someone prefer the first notation?

Once a value has been constructed, how can I access its fields?

Is there a way to create values using named parameters?

Thanks! 

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