Scanning a line for a pattern ( cat ${0} | while read line )

Question

I am busy to create a dynamicaly menu from items inside the script itself.
I will create some self reading/scanning code what builds the menu.
When script get executed, it will look for itself on disk put it in a catalog and scan every line with an 'if' 'elfi' for '[ $choice -eq X ]; then'.
Then next non empty line for '# title - description of code' part behind that if or elfi line, put that and the choice no. in $menuItemN var what is used to print the menu.
with
# start self scanning code
cat ${0} | while read line
# end self scanning code
# create menu
# the the chosen code between if's
if [ $choice -eq 1 ] ; then
# title - Drink coffee
elfi [ $choice -eq 2 ] ; then
# title - Eat pizza
This line of code
if [[ "$line" = ?(el)if*([[:space:]])*$choice*([[:space:]])-eq* ]] ; then
reads the if's and elfi's fine, but also f.e the line itself.
So I want to narrow down things, but I cant figure out how to use [ in a pattern.
What do I have to put at the XXXXX
if [[ "$line" = ?(el)if*([[:space:]])XXXX*$choice*([[:space:]])-eq* ]] ; then
so that that line is only accepting ( one left square bracket and different number of spaces )
if [ $choice -eq 1 ] ; then
or
elif [ $choice -eq 4 ] ; then
Basically how do I use the left and right bracket in a pattern?

Answer 1

After a good diner, but not helping with the dishes , this is for now my final.
I did create it in a way that I only need to add code in the runLoop function. I don't need to alter var's, code or any thing else outside the runLoop. And it works fine.
#!/bin/sh
shopt -s extglob ## enable extended globs +(...), *(...), etc...
declare -a menuArray
handle_menu()
## print menu
printf "_____________________________________________________________
for index in {0..99}
do
if [[ -n "${menuArray[$index]}" ]]; then
if [[ "$index" == "$exitChoice" ]]; then
printf "
fi
printf " %3s. %s
" "$index" "${menuArray[$index]}"
fi
done
printf "_____________________________________________________________
## read user input
read -p " Please choose an option :" choice
## user want to quit?
if [[ $choice -eq $exitChoice ]] ; then
printf " Bye bye!
exit 0
fi
## user did choose a wrong number?
if [[ ! -n "${menuArray[$choice]}" ]]; then
printf "
## ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
printf " # # # %s is Not an existing option!
" "$choice"
printf " # #
printf " # # Try again ( %s for exit )
" "${exitChoice}"
printf " #
printf " # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
fi
build_menu()
## Build a menu by reading this script
exitChoice=99 ## exit option number
exitStr="Exit" ## exit menu text
loopChoice=999 ## keeps the runloop rolling
lineno=0
while read line
do
((lineno++))
#echo - $line
if [[ $line = ?(el)if+([[:space:]])[[+([[:space:]])$choice+([[:space:]])-eq+([[:space:]])?([1-9][0-9 ])*([[:space:]])]]+([[:space:]]);+([[:space:]])then* ]] ; then
## line should look like 'if [[ $choice -eq 1 ]] ; then' or 'elif [[ $choice -eq 2 ]] ; then # help'
## Between the different elements there has to be 1 or more spaces
## There could be a comment behind the statement
#echo -
#echo - "before :${line}--"
line="${line%*([[:space:]])#*}" ## remove comments
line="${line%%+([[:space:]])}" ## remove trailing spaces
read title_line
((lineno++))
#echo - "before N:${nline}--"
title_line="${title_line%%+([[:space:]])}" ## remove trailing spaces
if [[ "$title_line" = #*([[:space:]])[Tt]itle*([[:space:]])-*([[:space:]])+([[:alnum:]])* ]]; then
## line should look like '# Tilte - Description'
## Between the different element there has to be 1 or more spaces
## The 'T' of 'Title' text must be an upper or lowercase letter
## get choice number from line
line="${line#?(el)if+([[:space:]])[[+([[:space:]])$choice+([[:space:]])-eq+([[:space:]])}"
#echo - "Tear off beginning:${line}--"
choiceNo="${line%%+([[:space:]])*}"
#echo - "Tear off end :${choiceNo}--"
## compare if choice number already exists and if exists: Bail out wit error notification
if [[ "${menuArray[$choiceNo]}" == "" ]]; then
## get title
title_line="${title_line##*([[:space:]])[Tt]itle*([[:space:]])-+([[:space:]])}"
#echo - "Tear off beginning:${title_line}--"
title_line="${title_line%%+([[:space:]])}"
#echo - "Tear off end :${title_line}--"
## add to menu
menuArray[$choiceNo]="${title_line}"
else
errLine=$((lineno-1))
printf "
## ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
printf " ## # Choice number already exists under name%s
" "${menuArray[choiceNo]} "
printf " ## #
printf " ## # Correct your code ( choice number? ) at line %s
" "${errLine}"
printf " # Wil bail out!
printf " ## ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
exit 1
fi
else ## no title in line
errLine=$lineno
printf "
## ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
printf " ## # Line after 'if' or 'elif' statement has no Title line
printf " ## #
printf " ## # Correct your code af line %s
" "${errLine}"
printf " # Wil bail out!
printf " ## ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
exit 1
fi ## if Title is there
fi
done <${0}
## add the exit code and title at the end of the menu array
menuArray[$exitChoice]=${exitStr}
start()
build_menu
choice=$loopChoice
# Loop while the variable choice is equal 999 ( defaultChoice )
while [ $choice -eq ${loopChoice} ]; do
# print menu + read user input
handle_menu
runLoop
choice=$loopChoice # only bail out on exit code ( at least default value 90 )
done
runLoop()
## this function should contain the choices with their code.
## the choice if statement should look like the following way
## 'if [[ $choice -eq 1 ]] ; then'
## or/and
## 'elif [[ $choice -eq 2 ]] ; then # help'
## YES, it should use $choice as a variable!!
## With in the next line the title, supplied in the following pattern
## '# title - Eat pizza'
## No need to put extra code in your code to have this running
## -------- insert your code here --------------------------------------------
if [[ $choice -eq 1 ]] ; then
# title - Drink coffee
echo Drink beer
elif [[ $choice -eq 2 ]] ; then # help
# title - Eat pizza
echo Eat pizza
elif [[ $choice -eq 4 ]] ; then
# title - Go Home
echo "Go Home!"
elif [[ $choice -eq 9 ]] ; then
# title - Get out
echo "Get out!"
elif [[ $choice -eq 44 ]] ; then # ln;ln lknbl bs
# title - Go to bed
echo "44 Go sleep!"
## -------- insert your code in front of this line ----------------------------
fi ## keep this as last
# Start point
start
exit 0
Still one question.
Is there a kind of way to walk through an array and get directly the existing variables with a index number?
Now I use
for index in {0..99}
do
if [[ -n "${menuArray[$index]}" ]]; then
if [[ "$index" == "$exitChoice" ]]; then
printf "
fi
printf " %3s. %s
" "$index" "${menuArray[$index]}"
fi
done
I don't want a loop ( {0..99} ) and a known last index number ( 99 )
Is there a way to find out the width om the current shell window?
Also other hints, remarks are welcome.
P.s if someone want to see the 'debug echo output', find&replace '#echo -' with 'echo -' and the other way arround