[Info-vax] %PCSIUI-E-PRIVCLASS1 when using PRODUCT with PIPE

[VAXman- at SendSpamHere.ORG]

In article <pupbbr$m32$1 at dont-email.me>, Chris Scheers <chris at applied-synergy.com> writes:
>Tim Sneddon wrote:
>> Jairo Alves <jairo.ptbr at gmail.com> wrote:
>>>> That is a DCL command procedure invocation.  That command procedure 
>>>> specifies the input be from the TT device.  That then creates the DCL 
>>>> equivalent of a subshell.  And the output from DCL procedure 
>>>> invocations can be redirected.
>>>>
>>> I see. It's a subshell, not a "pseudo-command file". I tried out of
>>> curiosity to run a loop in that command, and sure enough, DCL throws an
>>> exception, precisely because it is not emulating a command file, but
>>> instead a sub shell, where loops are forbidden.
>>>
>>> I> @TT:
>>> _I> n = 0
>>> _I> loop:
>>> %DCL-W-NOLBLS, label ignored - use only within command procedures
>>>  \LOOP:\
>>> _I> wr sys$output n
>>> 0
>>> _>  Exit
>>>
>> 
>> It is being treated as a command procedure.  Years ago I investigated
>> this as I was trying to figure a way to provide a better implementation
>> of $(SHELL ...) for MMK.  DCL actually checks to see if the command
>> procedure is disk based or not.  If it is disk based, then certain
>> constructs become possible, like multi-line IF-THEN-ELSE-ENDIF, loops,
>> etc. If not, then you get single-line DCL.
>> 
>> If I had more time I'd dig out the specific place in the listings
>> where this is checked.  Maybe VAXman (a.k.a Brian) has it memorised,
>> he has done quite of bit in the DCL space over the years.
>> 
>> Regards, Tim.
>
>IIRC, DCL records the RFA for labels and ELSE/ENDIFs statement so that 
>they can be directly skipped to.

Correct!  If DCL encounters <label>: when processing the procedure, a
symbol is created, a label symbol, of name <label> and the RFa of the 
source where it was encountered is the symbol's value.  If a control
command uses <label> as a target, DCL can immediately transfer to the
record identified by the RFA.  If the label specified in the control
command has not yet been encountered, (ie, there's no label symol) a
scan of the file ensues to locate <label>: and create the label symbol
before the transfer of control.



>If it is not an RMS disk file, records don't have an RFA.

Yup.  It has to be a random access device.



>Another way to put it: The statements are not recorded and you can't 
>rewind a terminal.

A terminal is not a random access device.



To answer Tim's assertion, I believe this is checked for in the module
INDIRECT.

-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

I speak to machines with the voice of humanity.