| RE: passing string parameter [message #7207] |
Sun, 20 October 1996 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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George McCabe <george@replica.gsfc.nasa.gov> writes:
> I want to write a small help procedure to display brief summaries
> of home made commands.
> IDL> helpme, command_name_string
> Is there a way to pass command_name_string to the procedure helpme
> without quotes?
If I understand this question correctly, I think you want to be able
to say:
HELPME, myCommand
And have your HELPME procedure interrpret "myCommand" as a string.
I can't think of any way to do this.
But I am sensitive to the problem. Let me suggest an alternative
approach. I define a HELP keyword for all my programs, so that
if I can't remember how to use them, I call them with the HELP
keyword set. If the HELP keyword is set, they print out a short
helpful message about how to use the program and return. Here
is an example of a little program named DOIT:
PRO DOIT, data, HELP=help
IF KEYWORD_SET(help) THEN BEGIN
PRINT, 'DOIT, data'
RETURN
ENDIF
PLOT, data
END
I picked up this little trick from Ray Sterner at Johns Hopkins
Applied Physics Lab, an excellent IDL programmer who always
writes programs that are *fully* documented.
Yours,
David
--
David Fanning, Ph.D.
Phone: 970-221-0438
Fax: 970-221-4728
E-Mail: davidf@fortnet.org
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| Re: passing string parameter [message #7211 is a reply to message #7207] |
Fri, 18 October 1996 00:00  |
Peter Mason
Messages: 145
Registered: June 1996
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Senior Member |
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On Wed, 16 Oct 1996, daytime visitor ssg login wrote:
> Hello, I want to write a small help procedure to display breif summaries
> of home made commands.
>
> IDL> helpme, command_name_string
>
> Is there a way to pass command_name_string to the procedure helpme
> without quotes?
If the people using your programs only use IDL to run applications - i.e.,
don't use IDL's command-line functionality, then you might consider
running a little "shell" program to catch certain errors.
I've included an example "shell" program at the end of this posting. It
reads a string from the console, calls EXECUTE() to execute it, and traps
& fixes "undefined variable" errors by turning "variables" into string
constants.
Because it uses EXECUTE(), it doesn't have all of the functionality of the
(proper) IDL command line. e.g., You can't run executive commands
(like ".run") or bring up online help from it. You're also not supposed
to be able to define new variables ( e.g., a=100 ) in it, but this seems
to work (at least, with full IDL on DEC OSF).
I'm sure that any IDL command-line jockey will consider it to be a truly
disgusting hack, but here it is anyway.
Peter Mason
pro shell
; This will stop execute() reporting errors, and will
; also catch ^D etc
catch,e &if (e ne 0) then goto,here
go=1 &s=''
while(go) do begin
here:
try=0
read,s,prom='IDL 2> '
t=strupcase(strtrim(s,2))
if (t eq 'EXIT') or (t eq 'QUIT') then go=0 $
else if (t eq '?') then begin
print,'Sorry, you can''t activate online help from here' &goto,here
endif else begin
there:
if (execute(s) ne 1) then begin ;some error in execute()
if (!error eq -128) then begin ;undefined var - handle it!
try=try+1 &if (try gt 0) then goto,here ;only try to fix once
j=rstrpos(s,',') ;just before problem varname in user's command
if (j le 0) then goto,here ;? - just back to prompt
t=strmid(s,j+1,strlen(s)-j-1) ;the problem varname
s=strmid(s,0,j+1)+"'"+strtrim(t,2)+"'" ;stringify the "varname"
goto,there ;NOW try the execute
endif else begin ;some other error - just report & back to prompt
print,!err_string &print,!syserr_string &goto,here
endelse
endif
endelse
endwhile
return ;you might want EXIT here instead
end
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| Re: passing string parameter [message #7216 is a reply to message #7211] |
Thu, 17 October 1996 00:00 |
Tim Patterson
Messages: 65
Registered: October 1995
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Member |
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daytime visitor ssg login wrote:
>
> Hello, I want to write a small help procedure to display breif summaries
> of home made commands.
>
> IDL> helpme, command_name_string
>
> Is there a way to pass command_name_string to the procedure helpme
> without quotes?
>
> George McCabe, george@replica.gsfc.nasa.gov
if the command is for example, sortnames, I don't think
it's possible to pass it into a procedure as
IDL> helpme, sortnames
(as you'vbe obviously discovered! :)
You have to use
IDL> helpme, 'sortnames'
Or do it in two stages
IDL> sortnames='sortnames'
IDL> helpme, sortnames
You could use this second method by having a file that
initialises the helpme tool. This file could define
string variables containing the command names e.g.
;; list of commands
sortnames = 'sortnames'
printnames = 'printnames'
anothercommand = 'anothercommand'
and so on
Then when you start IDL, the user enters
IDL > @helpme_init
to define all the variables and thereafter he
can just use the helpme system as
IDL> helpme, printnames
and so on. Not elegant, but it should work ok.
Maybe somebody will come up with a better idea! Be interesting
to see
Tim
--
http://condor.lpl.arizona.edu/~tim/
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