Newbie Question about procedures

[sbix]

Hi experts,
in shell scripts funcion must be defined before the main code invokes them.
i.e. like the following:
#!/bin/sh
sub1 (){
blah blah
}

#
# MAIN
#
sub 1
exit

Is it the same also for TCL ?

 

[feherke]

Hi

Yes. Given that procedures can be redefined anytime, that is the only way it can work.

[b]proc[/b] foo {} { [b]puts[/b] one }

foo

[b]proc[/b] foo {} { [b]puts[/b] two }

foo

[b]proc[/b] foo {} { [b]puts[/b] three }

foo

[blue]master #[/blue] tclsh proc-sample.tcl]
one
two
three

Feherke.
feherke.github.io

 

[Bong]

There is sort of an exception when dealing with Tk GUI's. If you invoke a procedure from, say, a button, that procedure doesn't have to be defined in preceding lines. Obviously it must be defined by the time the user pushes the button.

_________________
Bob Rashkin

 

[feherke]

Hi

Correct.

As the question was "Is it the same also for TCL ?", the answer is the same yes. Just as in Tcl, in shell scripts the functions definition has to occur before the call in time, not in space.

Maybe this is a better example :

[b]select[/b] action [b]in[/b] [green][i]'Load function'[/i][/green] [green][i]'Call function'[/i][/green]; [b]do[/b]
  [b]case[/b] [green][i]"$action"[/i][/green] [b]in[/b]
    [green][i]'Load function'[/i][/green]) . [green][i]'function-definition.sh'[/i][/green] ;;
    [green][i]'Call function'[/i][/green]) go_function_go ;;
    *) [b]break[/b] ;;
  [b]esac[/b]
[b]done[/b]

go_function_go()
{
  [b]echo[/b] [green][i]'Hello World !'[/i][/green]
}

[blue]master #[/blue] bash function-sample.sh
1) Load function
2) Call function
[blue]#?[/blue] 2
function-sample.sh: line 5: go_function_go: command not found
[blue]#?[/blue] 1
[blue]#?[/blue] 2
Hello World !

Feherke.
feherke.github.io