Set vars (by reference) in function

UNIX for Advanced & Expert Users
1

Hello everyone,
I am curious to find a possible way of doing something like this in ksh:
call a function and have that function set the value of the variable that the function knows by the name of $1....
example:

#! /bin/ksh
set_var(){
case $1 in
var1) this is where I would like to set var1 to a particular value;;
var2) this is where I would like to set var2 to a particular value;;
var3) this is where I would like to set var3 to a particular value;;
esac
}

set_var "var1"
set_var "var2"
set_var "var3"
# Now I would like to see what these values where set
echo $var1
echo $var2
echo $var3

Is this possible?
Hope you can help give me ideas.
Thanks.

2 
#!/bin/ksh
set_var()
{
case "$1" in
      "var1") var1="houston";;
      "var2") var2="boston";;
      "var3") var3="new york";;
esac
}

set_var "var1"
set_var "var2"
set_var "var3"
# Now I would like to see what these values where set
echo "${var1}"
echo "${var2}"
echo "${var3}"
3

Well, what I would like to achieve inside the function is a statement somewhat like:

$1="houston"

inside my case statement, see, I do not want to have to explicitly key the var name since it has been passed to the function and it knows its name .....

4

Is this what you're looking for?

[rick@kangaroo ~]$ cat kshtest.ksh 
#!/bin/ksh

export $1=$2

eval echo $1 = $(echo \$$1)
[rick@kangaroo ~]$ ./kshtest.ksh var1 houston
var1 = houston
[rick@kangaroo ~]$ ./kshtest.ksh var2 dallas
var2 = dallas
[rick@kangaroo ~]$

-----Post Update-----

After reading this again, I'm confused. . .

Will var1, var2, etc. always be set to Houston? If so, then

export $1="Houston"

will work. If not, then the name of the variable must be in the case statement. Otherwise, how will the function know which value to assign? The explicit names of the variables will have to be typed as part of the case statement.

5 
#! /bin/ksh93

set_var()
{
   case $1 in
      var1)  eval $1=1 ;;
      var2)  eval $2=2 ;;
      var3)  eval $3=3 ;;
   esac
}

set_var "var1"
set_var "var2"
set_var "var3"

# Now I would like to see what these values where set
echo $var1
echo $var2
echo $var3

gives

1
2
3
6

Is this only good for ksh93 or was it already ok for ksh88 ?
Thanks!

7

Yes, will work with ksh88 also.

8

Thanks, I changed to :
case $1 in
var1) eval $1=1 ;;
var2) eval $1=2 ;;
var3) eval $1=3 ;;
esac
............Thanks a lot! It works great