[CST-2] Types (NOT Opt Comp.) 1997/7/10

[Alvin]

Hmm, maybe it just means whether generalisation is possible.  Eg the tuple
rule:

G |- M1 : t1    G |- M2 : t2
-----------------------------
    G |- (M1,M2) : t1 x t2

Is a generalised form of

G |- M1 : r     G |- M2 : r
---------------------------
    G |- (M1,M2) : r x r

Similarly for integers, functions etc

Total guess, but it makes sense.

Alvin

> Sorry I just realised the mistake. The question (repeated below) is
> clearly about Types, not Opt. Comp.
> 
> Mat
> 
>> The question asks to explain the notion of a principal type. Presumably
>> the answer to this is that the principle type is just the principal type
>> scheme.
>> Then it also asks whether the set of type inference rules (for an ML-like
>> language), which you had to give in the previous part of the question, has
>> this propery.
>> I am a bit confused as to how type inference rules exhibit a principal
>> type property? Anyone?
>> thanks,
>> 
>> Mat
>> 
>> Matej Pfajfar
>> St John's College, University of Cambridge, UK
>> 
>> GPG Public Key @ http://matejpfajfar.co.uk/keys
>> Most people are good people, the rest of us are going to
>> run the world. -- badbytes
>> 
>> WARNING: THIS E-MAIL ACCOUNT WILL BE DELETED ON
>>          30/09/2002. PLEASE USE mp@cantab.net.
>> 
>> 
>> 
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> 
> Matej Pfajfar
> St John's College, University of Cambridge, UK
> 
> GPG Public Key @ http://matejpfajfar.co.uk/keys
> Most people are good people, the rest of us are going to
> run the world. -- badbytes
> 
> WARNING: THIS E-MAIL ACCOUNT WILL BE DELETED ON
>        30/09/2002. PLEASE USE mp@cantab.net.
> 
> 
> 
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