Function called only once in a "for" statement

[bousmart]

Hello,

I'm making a script (ksh) where I'm trying to call a function that I defined in the same script several times. I order to do that, I tried to put it inside a "for" cycle as follows:

for (cnt=0; cnt<10; cnt=cnt+1)
do
...some code...
MyFunction
...
done

---------

The intention is to call the function "MyFunction" repetitively.

I noticed that MyFunction got called the first time (it entered the for cycle), but for some reason, once the function exits, the cycle is broken, and the script continues with the code after the "done" statement.

In the example above, I would expect the script to call MyFunction 10 times, not only 1.

Does anyone know if this is valid? If so, am I doing anything wrong?

Thanks!

[wje_lf]

Hmmm. That's strange. When I tried this script:

#!/bin/ksh

for (cnt=0; cnt<10; cnt=cnt+1)
do
  echo hi
done

all I got was this:

wally:~/friday$ h.sh
./h.sh: syntax error at line 3: `(' unexpected
wally:~/friday$

How could you have possibly gotten further?

There's a piece of the puzzle that's missing here. Could you post a small script that demonstrates this for loop calling MyFunction once and only once?

[sixstringartist]

Your syntax is incorrect.

#!/bin/ksh

for (( cnt=0; cnt<10; cnt=cnt+1 ))
do
  echo hi
done

exit 0

The above is a working script.

I havent tested it, but I assume the missing parentheses are the cause of the OP's issues as well.

[bousmart]

Well yes, I just wanted you show more less what I was trying to do. Actually, its something like this:

mylist=(a b c d e)

for (( cnt=0; cnt<${#mylist[@]}; cnt++ )); do

currentitem=${mylist[$((cnt))]}
myFunction

done

-------------

In here, "MyFunction" does something different, depending on the value of "currentitem".

Any help is appreciated!

[jozyba]

The intention is to call the function "MyFunction" repetitively.

I noticed that MyFunction got called the first time (it entered the for cycle), but for some reason, once the function exits, the cycle is broken, and the script continues with the code after the "done" statement.

Maybe there's something wrong with 'myFunction' ?

This seems to work okay:

#! /usr/bin/ksh

myFunction() {
  case $currentitem in
    a)  echo "myFunction called" $((cnt+1)) "time   :  $currentitem"  ;;
    b)  echo "myFunction called" $((cnt+1)) "times  :  $currentitem"  ;;
    c)  echo "myFunction called" $((cnt+1)) "times  :  $currentitem"  ;;
    d)  echo "myFunction called" $((cnt+1)) "times  :  $currentitem"  ;;
    e)  echo "myFunction called" $((cnt+1)) "times  :  $currentitem"  ;;
  esac
}

mylist=(a b c d e)

for (( cnt=0; cnt<${#mylist[@]}; cnt++ )); do
    currentitem=${mylist[${cnt}]}
    myFunction
done

Edit....I've altered '${mylist[$((cnt))]}' to '${mylist[${cnt}]}' as sixstringartist suggests in the next message.

[sixstringartist]

Yes, my post was referring to the post above mine in which he used incorrect syntax.

Your for loop seems fine so perhaps you should post your function.

Also, Im a bit confused by this syntax:

currentitem=${mylist[$((cnt))]}

It works, but Ive never seen a variable referenced as $((var)). Why do you use that instead of ${mylist[${cnt}]}?

[Franklin52]

I should use a function with a parameter and a "for in" loop to loop through the items like this:

#!/bin/sh

myFunction()
{
  echo Item = $1
}

list="a b c d"

for i in $list
do
  myFunction $i
done

Regards

[bousmart]

Thanks a lot for your posts!!!

There is no specific reason for the $((var)) convention. I saw it that way somewhere else and it worked for me. Changing it to what you suggested returns the same result. Something that is interesting to note here is that my script contains a bunch of "for/done" loops and they all work fine, except for the one that calls another function.

I didn't want to go into many details because I thought my problem was more straightforward, but seeing that it's not here goes the rest of the story:

"MyFunction" is actually a helper function that builds a directory list, based on the content of "currentitem". It is basically a set of "if/fi" pairs, as depicted below:

if [[ $currentitem = "a" ]]; then
directorylist=(
/dir1/dir2
/dir1/dir3
/dir1/dir3/dir4
)

if [[ $currentitem = "b" ]]; then
.....

--------------

However, inside every if/fi pair, I call another function that processes those directories. In short, the whole thing looks like this (please note that this will not compile, it has been shortened for easy reading):

main()
{
for (...)

...do something...
MyFunction

done
}
##########

MyFunction()
{
if [ currentitem = a ]; then
directorylist= (...)
Another_function()
fi

if [ currentitem = b ]; then
directorylist= (...)
Another_function()
fi

if [ currentitem = c ]; then
directorylist= (...)
Another_function()
fi

...
}

##########

Another function()
for (( cnt=0; cnt<${#directorylist[@]}; cnt++ )); do
...do something with the files in those directories...
done
}

main $*
# END OF SCRIPT

--------------------------

In the script above, in the main() function, if I comment "MyFunction", the loop is made withouth problems.

When I uncomment it, the loop is executed once (only for the first "currentitem") and then it exits and continues with the rest of the script. This means that there were no errors (I set -e since the beginning of the script) and there were not "exit"/"return" calls either.

[Franklin52]

Try to run the script in debug mode with the -x option.

Regards