Operational semantics. Was: [Haskell-cafe] What unsafeInterleaveIO is unsafe

[Bernie Pope]

On 17/03/2009, at 1:13 PM, Jonathan Cast wrote:

> [Totally OT tangent: How did operational semantics come to get its  
> noun?
> The more I think about it, the more it seems like a precís of the
> implementation, rather than a truly semantic part of a language
> specification.]

I haven't followed the whole thread, so perhaps I'm missing some  
important context to this question.

It is true that operational semantics are often used to summarise or  
explain an _implementation_ of a language feature, but I wouldn't say  
that they are always used in this way. An operational semantics may be  
used to define a "behaviour" function: (program x input) -> outcome.  
The big-step style of operational semantics style tends to be less  
like an implementation, and more like a specification. Perhaps the  
more crucial part of operational semantics is that it just deals with  
syntactic terms as its "values".

Apologies if this has nothing to do with your question.

Cheers,
Bernie.