#!/usr/bin/env sh
# YES_ZSH
# YES_BASH
# YES_DASH
# YES_ASH

has() ( ### @- print the result of `which` if the program is found, else simply return 1.
    ### ```
    ### export SOLVER="$(has kissat || has picosat || has cadical || has minisat)"
    ### ```
    if [ "${1:--}" = "${1#*[!A-Za-z_]}" ]; then # valid alias name?
        # forcefully unalias it (regardless of if it even was an alias)
        alias "$1"=
        unalias "$1"
        # forcefully unset it (regardless of if it even was a function)
        eval "$1() (:)"
        unset -f "$1"
    fi
    which -- "$1" >/dev/null 2>&1 && which -- "$1"
) # this uses parentheses instead of braces so that the function is always run
#   in a subshell. otherwise, the user's aliases and functions may be overwritten.

[ -n "${preload+-}" ] || has "$@"