#11 Getting the next or specified scan in a file

[Jeff Mangum]

(1) After using keep to write a summed and calibrated
scan, one usually just wants to "get" it thereafter.
The get,scan= construct is a bit clumsy. How about a
"next" parameter that gets the next scan in an input file?

(2) Similarly, instead of having to use the
"get,scan=#" construct to get a scan, how about a
"getscan,#" procedure?

(3) Also similarly, could procedures like getfs be
included in the features requested in (1) and (2) above?

[Tom Bania]

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Jeff M. has basically asked for the CLASS getfirst and
getnext constructions.
this would normally be used on processed data which was
calibrated, written
out to a file and then reattached via a filein command.

this request would be trivial to service were you to define
a !g.lastrec
system variable:

proc gv ; get first record in the attached file
;
on_error,2
;
!g.lastrec=0
;
getrec,!g.lastrec
;
return
end

proc gn ; get next record in the attached file
;
on_error,2
;
!g.lastrec=!g.lastrec+1
;
getrec,!g.lastrec
;
return
end

[Tom Bania]

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should have been: " proc gf "

jeff

you could also define your own globals via a procedure invoked
in a .gbtidl startup script (needs to be a .pro if you want
to get
returned back to the script)

e.g.

!class.lastrec

so, jeff, you could start writing procedures that make GBTIDL
look and act exactly like the good things in CLASS...

[Jeff Mangum]

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Thanks Tom and Bob. That should do the trick. -- Jeff

[Jeff Mangum]

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Bob: Can you tell me how to define a global variable?
Didn't see how to do this in the documentation. Thanks.

-- Jeff