Two similar shell functions that run different programs

Question

I have a script that contains two shell functions:

runhaskells() {
 local DIR=$PWD
 local TARGET="cabal.sandbox.config"
 while [[ ! -e $DIR/$TARGET -a $DIR != "/" ]]; do
 DIR=$(dirname $DIR)
 done
 if [[ $DIR != "/" ]]; then
 local DB=$(sed -ne '/^package-db: */{s///p;q;}' "$DIR/$TARGET")
 runhaskell -no-user-package-db -package-db="$DB" "$@"
 else
 runhaskell "$@"
 fi
} 
ghcs() {
 local DIR=$PWD
 local TARGET="cabal.sandbox.config"
 while [[ ! -e $DIR/$TARGET -a $DIR != "/" ]]; do
 DIR=$(dirname $DIR)
 done
 if [[ $DIR != "/" ]]; then
 local DB=$(sed -ne '/^package-db: */{s///p;q;}' "$DIR/$TARGET")
 ghc -no-user-package-db -package-db="$DB" "$@"
 else
 ghc "$@"
 fi
} 

which obviously is a repeat of each other except for the fact that it calls a different program in each function. The first function calls the runhaskell program while the second function calls the ghc program.

How can I DRY this script (either zsh or bash syntax is fine for me) with the end goal that I should be able to call either function at the command line?

Answer 1

Two simple bash solutions I can think of are:

1. Use a shell script and 0ドル/$BASH_SOURCE to determine the calling name and a symlink from one name to the other.

2. Two small wrapper functions.

   h() {
    local DIR=$PWD
    local TARGET="cabal.sandbox.config"
    while [[ ! -e $DIR/$TARGET -a $DIR != "/" ]]; do
    DIR=$(dirname $DIR)
    done
    if [[ $DIR != "/" ]]; then
    local DB=$(sed -ne '/^package-db: */{s///p;q;}' "$DIR/$TARGET")
    set -- "${@:1:1}" -no-user-package-db -package-db="$DB" "${@:2}"
    # or this is the order of original arguments and added arguments don't matter
    set -- "$@" -no-user-package-db -package-db="$DB"
    fi
    "$@"
   }
   runhaskells() {
    h runhaskell "$@"
   }
   ghcs() {
    h ghc "$@"
   }
   

Slightly DRYier version of the above which uses bash's FUNCNAME array.

 h() {
 local DIR=$PWD
 local TARGET="cabal.sandbox.config"
 while [[ ! -e $DIR/$TARGET -a $DIR != "/" ]]; do
 DIR=$(dirname $DIR)
 done
 if [[ $DIR != "/" ]]; then
 local DB=$(sed -ne '/^package-db: */{s///p;q;}' "$DIR/$TARGET")
 set -- "${@:1:1}" -no-user-package-db -package-db="$DB" "${@:2}"
 # or this is the order of original arguments and added arguments don't matter
 set -- "$@" -no-user-package-db -package-db="$DB"
 fi
 "${FUNCNAME[1]%s}" "$@"
 }
 runhaskells() {
 h "$@"
 }
 ghcs() {
 h "$@"
 }