[Info-vax] Some questions on software for VMS 7.3 VAX

[David Froble]

Johnny Billquist wrote:
> On 2016-01-01 21:27, David Froble wrote:
>> Stephen Hoffman wrote:
>>> On 2016-01-01 15:31:47 +0000, David Froble said:
>>>
>>>> lists at openmailbox.org wrote:
>>>>>
>>>>> BTW is the BASIC on VAX/VMS a true compiler or is it interpreted?
>>>>
>>>> Ya know, that's really funny.  You say you don't like Basic, but you
>>>> don't even know what it is.  It's a true compiler, with only one
>>>> fault that I'm aware of. I didn't even know about the fault until
>>>> John Reagan (spell?) explained it.
>>>
>>> The BASIC layered product provides both an interpreter and a compiler
>>> on VAX.   There's no JIT associated with the interpreter, however.
>>>
>>>
>>
>> At the time it was developed, the Basic guys called it "incremental
>> compilation", as to differentiate it from the interpreter on RSTS/E.
>>
>> Not sure how much different it is.
> 
> While I don't know specifically about VMS BASIC, BASIC+2 is indeed 
> compiling, even when in immediate mode. It compiles the program when you 
> type "RUN", or compiles individual lines as you press enter. So it never 
> "interprets" the lines in the common sense of the word. But the 
> compilation only goes to object code in this case, which is loaded into 
> memory and executed under the context of the BASIC itself. You can even 
> load other object files to be included when running, if your program is 
> split into several modules. But, no proper linking using the task 
> builder. And it was optional if you wanted to include this ability or not.
> 
> I would have assumed that VMS BASIC did the same, but like I said, I 
> don't really know.
> 
>     Johnny
> 

I believe it is the same.  After all, VMS has RSX as some of it's roots and such.

In the VAX Basic runtime environment, a number of options can be set, including 
an OLB to use.  Thus, I can execute a line of code, which might call a module in 
the OLB.

Not really an interpreter as I understand the term.