shellfu-bash-saturnin/src/libexec/saturnin-ln

#!/bin/bash

. $(ffoom path)

ffoo import pretty

DEFAULT_TARGET=$HOME
TRY_RELPATH=true

PY_SCRIPT="
import os.path
import sys
src, dst = sys.argv[1:]
r = os.path.relpath(src, dst)
a = os.path.abspath(src)
if len(a) < len (r):
    print a
else:
    print r
"

usage() {
    usage_is "[-t|--target TARGET] [SOURCE] [NAME]"
}

expand_tilde() {
    #
    # Exchange "~" for home
    #
    perl -pe "s|^[[:space:]]*~|$HOME|"
}

maybe_relpath() {
    local src="$1"
    local dst="$2"
    $TRY_RELPATH || { echo "$src"; return 0; }
    {
        echo 'import os.path'
        echo 'import sys'
        echo 'src, dst = sys.argv[1:]'
        echo 'r = os.path.relpath(src, dst)'
        echo 'a = os.path.abspath(src)'
        echo 'if len(a) < len (r):'
        echo '    print a'
        echo 'else:'
        echo '    print r'
    } | python "$src" "$dst"
}

link() {
    local src=$1
    local dst=$2
    debug -v src dst
    if $TRY_RELPATH;
    then
        src=$(python <(echo "$PY_SCRIPT") "$src" "$(dirname $dst)")
    fi
    think "linking $src to $dst"
    rm -f $dst
    ln -s $src $dst
}

load() {
    saturnin conf -p ln.dir.$1 | expand_tilde
}

while true; do case $1 in
    -t|--target)        target=$2           shift 2 ;;
    --help)             usage                       ;;
    -*)                 usage                       ;;
    *)                  src=$1; name=$2;    break   ;;
esac done

test -z "$target"               && target=$(load target)
test -z "$target"               && target=$DEFAULT_TARGET
test -z "$name"                 && name="$(basename "$PWD")"
test -z "$src"                  && src="."

debug -v name target

mkdir -p $target
link $src $target/$name