tableize

#!/usr/bin/env dash

# TODO: keep track of which scripts require GNU versions of utilities,
#       as opposed of plain ol' busybox. test all the awk scripts, etc.

tableize() {
    local name="$1"
    local rc="$2"
    [ -n "$rc" ] || rc="$(readlink -f "$(dirname "$name")" )"
    [ -d "$rc" ] || { printf '%s: %s\n' "$0" 'failed to determine rc directory' >&2; }
    cd "$rc" || { printf '%s: %s\n' "$0" 'failed to change directory' >&2; }

    # the script column has to be stupid wide because names are repeated twice for anchors.
    # column lengths: 45, 10, 4, 4, 4, 4
    printf '%s\n' '| script                                        | preference | ash | bash | dash | ksh | mksh | oksh | osh | posh | yash | zsh |'
    printf '%s\n' '| --------------------------------------------- | ---------- | --- | ---- | ---- | --- | ---- | ---- | --- | ---- | ---- | --- |'

    local x_ash=0 x_bash=0 x_dash=0 x_ksh=0 x_mksh=0 x_oksh=0 x_osh=0 x_posh=0 x_yash=0 x_zsh=0

    local f=
    for f in sh/*; do
        [ ! -d "$f" ] || continue # do not recurse or anything
        [ -f "$f" ] || continue # probably failed to glob

        local fn="${f##*/}"
        # ignore some stuff:
        [ "$fn" = "${fn#_}" ] || continue # completion files
        [ "$fn" = "${fn%.bak}" ] || continue # backup files

        local i=0 ash= bash= dash= ksh= mksh= oksh= osh= posh= yash= zsh= pref=
        while IFS= read -r line; do
            : $((i+=1))
            [ $i -le 10 ] || break # act like head -n10

            #printf '%s\n' "$i: $line"
            local code="$line"
            code="${code#${code%%[! ]*}}" # ltrim
            local decom="$code"
            #decom="${decom#${decom%%[!#]*}}" # ltrim #s
            decom="${decom#\#}"
            [ "$code" != "$decom" ] || continue # only care about comments
            decom="${decom#${decom%%[! ]*}}" # ltrim
            decom="${decom%${decom##*[! ]}}" # rtrim

            _pref=
            case "$decom" in
                ('!/bin/sh') _pref=sh;;
                ('!/usr/bin/env ash') _pref=ash;;
                ('!/usr/bin/env bash') _pref=bash;;
                ('!/usr/bin/env dash') _pref=dash;;
                ('!/usr/bin/env false') _pref=false;;
                ('!/usr/bin/env perl') _pref=perl;;
                ('!/usr/bin/env sh') _pref=sh;;
                ('!/usr/bin/env zsh') _pref=zsh;;
                ('!/usr/bin/sh') _pref=sh;;
                #*) printf '\033[1mno match:\033[0m [%s]\n' "$decom";;
            esac

            if [ -n "$_pref" ]; then
                pref="$_pref"
                continue
            fi

            compat() { # be careful, we don't validate arguments
                [ "${1#+}" != "$1" ] && eval "${1#+}"=yes || eval "${1#-}"=no
            }

            check=0
            set -f
            IFS=' '
            for flag in $decom; do case "$flag" in
                (YES_ZSH) zsh=yes;;
                (YES_BASH) bash=yes;;
                (YES_DASH) dash=yes;;
                (YES_ASH) ash=yes;;
                (FAKE_COMPAT)
                    ash=yes bash=yes dash=yes
                    ksh=yes mksh=yes oksh=yes
                    osh=yes posh=yes yash=yes
                    zsh=yes;;
                (NO_ZSH) zsh=no;;
                (NO_BASH) bash=no;;
                (NO_DASH) dash=no;;
                (NO_ASH) ash=no;;
                (compat:) check=1;;
                ([+-][a-z]sh) [ "$check" = 0 ] || compat "$flag";;
                ([+-][a-z][a-z]sh) [ "$check" = 0 ] || compat "$flag";;
                ('#'*) break;;
            esac done
        done < "$f"

        #printf '%s' "script $fn has a preference for $pref and support for" >&2
        #[ "$zsh" != yes ] || printf ' %s' zsh >&2
        #[ "$bash" != yes ] || printf ' %s' bash >&2
        #[ "$dash" != yes ] || printf ' %s' dash >&2
        #[ "$ash" != yes ] || printf ' %s' ash >&2
        #printf '\n' >&2

        local yay='✔️'  # yay='y'
        local nay='⭕' # nay='✖️'  # nay='n'
        local huh='❔' # huh='?'
        local etc='*n/a*'

        # TODO: escape underscores in filenames.
        printf '| [%s](#%s) ' "$fn" "$fn"
        printf "%$(( 40 - 2 * ${#fn} ))s" '' # funky way to pad the rest of the column

        local p="$pref"
        [ "$pref" != false ] || p='**false**'
        [ "$pref" != perl ] || p='**perl**'
        [ "$pref" != sh ] || p='*sh*'
        [ -n "$p" ] && printf '| %10s ' "$p" || printf '| %9s%s ' '' "$huh"

        local n=
        for n in ash bash dash ksh mksh oksh osh posh yash zsh; do
            eval "local t=\$$n"
            [ "$t" != no ] || eval ": \$((x_$n+=1))"
            local w="$huh"
            [ "$pref" != perl ] || w="$etc"
            [ "$t" != yes ] || w="$yay"
            [ "$t" != no ] || w="$nay"
            # can't use '%4s' here because printf gets confused by UTF-8.
            printf '| %s    ' "$w"
        done
        printf '|\n'
    done

    local n=
    for n in ash bash dash ksh mksh oksh osh posh yash zsh; do
        eval "local x=\$x_$n"
        printf >&2 'incompatibilities for %4s: %2s\n' "$n" "$x"
    done
}

tableize "$0" "$@"