Passing multiple args to a tcl proc in one variable

[Wesley Combs]

I have a tcl proc that accepts multiple arguments like so

proc ECP_Send_Email {recipient email_server subject body} {

   #Do work here.

}

I want to call that proc sending it the arguments.

Well I want to pass all the arguments in one variable though, like so:

set strArgs {test@test.com myserver test test}

ECP_Send_Email $strArgs

is there a way to do this? Maybe a breakout command that will break out each of the items into a variable and pass it to the proc?

Thanks

Topic

[Charlie Bursell]

Sure.

Change the proc to:

proc procname {args} {

args will be a list of arguments passed.  You can pass as many as you like

[Tom Henderson]

Something like that.  First, put your arguments into a list variable, then use the eval command to call your proc with that list.  The eval command “flattens” your list so they look like individual variables.

Something like:

set listArgs

eval ECP_Send_Email $listArgs

The eval command will let you construct just about any command dynamically, then call it.  It works with lists, though, not strings.  Create the command as a list, then use eval.

But if you’re doing a proc call, you want to be sure that the list you’re passing to the proc has the same number of arguments as the proc is expecting, or you will get a run-time error.

[Troy Morton]

I personally prefer keyed lists.  This allows you to add or remove arguments to the proc without affecting the fucntionality or compatibility if the proc is being used in multiple places .. like so ..

Code:

         #
         # Populate the arguments to send to the proc SendEmailMessage
         # and call the proc.
         #
         keylset mailargs MH         $mh
         keylset mailargs TOFILE     $blnTrcWrite
         keylset mailargs HOSP       $msghosp
         keylset mailargs MAILTO     $mailto
         keylset mailargs MAILFROM   $mailfrom
         keylset mailargs MAILSUBJ   $mailsubj
         keylset mailargs MAILMSG    $mailmsg
         keylset mailargs MAILSERVER $mailserver
         keylset mailargs MAILDOMAIN $maildomain
         keylset mailargs MAILSTART  $mailstart
         keylset mailargs MAILSTOP   $mailstop

         SendEmailMessage $mailargs

… and in the called proc get the data out of the argument keyed list …

Code:

proc SendEmailMessage { mailargs } {

   keylget mailargs         MH mh
   keylget mailargs     TOFILE blnTrcWrite
   keylget mailargs       HOSP hosp
   keylget mailargs     MAILTO mailto
   keylget mailargs   MAILFROM mailfrom
   keylget mailargs   MAILSUBJ mailsubj
   keylget mailargs    MAILMSG mailmsg
   keylget mailargs MAILSERVER mailserver
   keylget mailargs MAILDOMAIN maildomain
   keylget mailargs  MAILSTART mailstart
   keylget mailargs   MAILSTOP mailstop

As I mentioned this gives you alot of flexibility to add or remove arguments and functionality to a proc while keeping it backwards compatible with other places its being used.

Also, it doesn’t matter what order you supply the arguments because the list is keyed.  So, you don’t have to remember that the first argument is X and the second is Y the third is Z and take a chance of putting them in the wrong order when calling the proc.

Hope this helps

[Scott Folley]

Yeah Troy, that is my favorite as well.  It is also nice to keep in mind that you can use optional arguments to a TCL proc like this:

proc SendEmailMessage { mailargs {debug “0”} } {

    if {$debug} {

           echo “I am in debug mode”

}

That way you can send all of your information in via the keyed list variable and add an additional variable to indicate whether you are in debug mode..

Just my $.02

[Author]

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