Re: The compilation approach in modern languages

Tony Finch <dot@dotat.at> wrote:
>"Rodney M. Bates" <rbates@southwind.net> wrote:
>>
>>The one exception is the functional languages, where functions can be,
>>in effect, manipulated at runtime and then evaluated. Obviously, it
>>is too late then for a traditional batch compile, and something more
>>like interpretation is needed, at least some of the time.
>
>That is not true for most modern functional programming languages
>(i.e. ones not descended from lisp) which are designed to be compiled
>to native code. It is also true for non-functional languages that have
>an "eval" function, which includes many scripting languages.


Yes.


And the equally important (and largely older) class of application
languages. One amusing example here is Genstat - designed entirely
by statisticians, and interestingly unusual :-)


As far as this aspect goes, there are really four levels:


Ones with no general 'eval' operation.


Ones where 'eval' executes entirely within its own scope.


Ones where 'eval' can behave as a declaration.


Ones where 'eval' can change the syntax accepted by the compiler.


It is reasonable to say that languages that allow the last cannot
be compiled and must be interpreted :-)


Regards,
Nick Maclaren.

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