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From: fraser@bilby.cs.uwa.oz.au (Fraser Wilson)
Newsgroups: comp.lang.functional
Subject: Re: A question about types in ML
Message-ID: <fraser.658398987@melomys>
Date: 12 Nov 90 08:36:27 GMT
References: <paula.658247771@shum>
Distribution: comp
Organization: Dept. Computer Science, University of Western Australia.
Lines: 19

In <paula.658247771@shum> paula@SHUM.HUJI.AC.IL (Paula Ross) writes:

>Is there any way in ML that you can create a data type which accepts
>sequences of objects of different types (when the number and types of the
>objects are not known in advance) ?
>i.e. can you create a list type without the restriction that each element of
>the list must be of the same type ?

As far as I know you can only do this using a union type, which means
you have to know what types you will get.  I don't think it can be done
for an arbitary type.


Fraser Wilson			| Of all the knights in Appledore
fraser@bilby.cs.uwa.oz		| The bravest was Sir Thomas Tom
				| He multiplied as far as four
There can be only one!		| And knew what nine was taken from
	- CM			| To make eleven.  He could write
				| A letter to another knight.	- A.A Milne