...

Defining a Subroutine

subroutine name
[script line 1]
...
[script line n]
endsub

Invoking a Subroutine

callsub name

Sequence of Defining / Invoking a Subroutine

...

For example, the following subroutine will function correctly:

subroutine test
   echo "This is subroutine test"
   echo "$(_halton)"
endsub

echo "This is main()"
callsub test

However, this subroutine will fail:

echo "This is main()"
callsub test

subroutine test
   echo "This is subroutine test"
   echo "$(_halton)"
endsub

Nesting / Recursion of Subroutines

...

For example, the following illustrates subroutine nesting:

subroutine a
    echo "Beginning subroutine A"
    callsub b
    echo "Ending subroutine A"
endsub

subroutine b
    echo "Beginning subroutine B"
    echo "Ending subroutine B"
endsub

callsub a

Example

subroutine loop_increment
        echo "inside loop_increment: $(LOOP)"
        set LOOP=<$(LOOP) + 1>
endsub

echo "Starting Loop:"
set LOOP=0
if <$(LOOP) LT 1>
        callsub loop_increment
end
if <$(LOOP) LT 2>
        callsub loop_increment
end
if <$(LOOP) EQ 2>
        callsub loop_increment
end
echo "Final Value of LOOP: $(LOOP)"

Output

Starting Loop:
inside loop_increment: 0
inside loop_increment: 1
inside loop_increment: 2
Final Value of LOOP: 3