Shell script with single choice options - bash

Question

I'm wondering, if it is possible to write a shell script with options using getopt or getopts that won't allow to combine multiple options?
E.g., my script could be ran in two possible modes - long or short and with alpha or beta options, that's why I would like to use ./script.sh -l -a , ./script.sh -l -b or ./script.sh -s -a , ./script.sh -s -b, but it shouldn't be possible to run both options -l and -s or -a and -b at the same time.
I know it can be made a lot easier, because I can make option -a which will run long version alpha, option -b which will run long version beta, option -c which will run short version alpha, and option -d which will run short version beta, but I want to use two options, just understand if such way is possible.
Please find below code with "options" to choose using simple read, what I want to convert into getopt(s)
#!/bin/bash
echo "Please insert the text:"
read text
echo
echo "You entered $text"
echo "Choose version:
1) Long
2) Short
3) Quit
-> "
read option
# OPTION 1
if [ "$option" == "1" ]; then
echo "Choose method:
1) alpha
2) beta"
read method
# METHOD 1
if [ "$method" == "1" ]; then
longalpha
fi
# METHOD 2
if [ "$method" == "2" ]; then
longbeta
fi
fi
#OPTION 2
if [ "$option" == "2" ]; then
echo "Choose method:
1) alpha
2) beta"
read method2
# METHOD 1
if [ "$method2" == "1" ]; then
shortalpha
fi
# METHOD 2
if [ "$method2" == "2" ]; then
shortbeta
fi
fi
if [ "$option" == "3" ]; then
echo "Good Bye!"
fi

Answer 1

You should parse all the options first, and set variables indicating which have been passed and which have not.
Then, before actually executing anything, test if -l and -s are both present or both missing, and if so exit with the appropriate error message.
You can perform a similar check with -a and -b
Once you know you have everything that is needed, but nothing more, then you can have your script perform the appropriate operation.

Answer 2

When running getopts you can check if an exclusive flag has already been set by having unset variables representing that flag.
Let's say you have two variables that will determine what you want to do, and they start unset:
unset vers meth
And you also have a lookup table for flags to actions, like:
declare -A flags=([l]=long [s]=short [a]=alpha [b]=beta)
Then you can run getopts like:
while getopts "lsab" opt; do
case $opt in
(l|s) [[ $vers ]] && fail # we already set $vers
vers=${flags[$opt]} ;;
(a|b) [[ $meth ]] && fail # we already set $meth
meth=${flags[$opt]} ;;
('?') fail ;; # we got some unknown option
esac
done
The only thing that remains is to check that we did get something for $vers and $meth:
[[ $vers && meth ]] || fail
And then execute your task:
$vers$method
The way you handle this last part depends on the specifics of your code, but since you are calling shortalpha, etc., this way fits well. If you are instead calling some external code, this might be like prog --$vers --$meth, etc.