# -*- mode: sh -*-

# Remove all occurrences of $1 from the path on stdin, and add
# it to the front.
move_to_front () {
    # First, give each element its own leading and trailing colon:
    # foo:bar -> :foo::bar:.  Then remove all instances of $1, add one
    # to the front, and put back in normal path form.
    sed \
        -e "s|:|::|g" \
        -e "s|..*|:&:|" \
        -e "s|:$1:||g" \
        -e "s|^|:$1:|" \
        -e "s|^:||" \
        -e "s|:$||" \
        -e "s|::*|:|g"
}

# Remove all occurrences of $1 from the path on stdin, and add
# it to the end.
move_to_back () {
    sed \
        -e "s|:|::|g" \
        -e "s|..*|:&:|" \
        -e "s|:$1:||g" \
        -e "s|\$|:$1:|" \
        -e "s|^:||" \
        -e "s|:$||" \
        -e "s|::*|:|g"
}

prepend () {
    eval "export $1=\"\$(echo \"\$$1\" | move_to_front '$2')\""
}

postpend () {
  eval "export $1=\"\$(echo \"\$$1\" | move_to_back '$2')\""
}

prepend_if_dir () {
  if [ -d "$2" ]; then
    prepend $1 "$2"
  fi
}

postpend_if_dir () {
  if [ -d "$2" ]; then
    postpend $1 "$2"
  fi
}

add_path () {
  prepend_if_dir PATH "$1"
}

add_path_after () {
  postpend_if_dir PATH "$1"
}

add_bin_man () {
    prepend_if_dir PATH $1/bin
    prepend_if_dir INFOPATH $1/info

    # You might think we should set MANPATH here too, but Linux man
    # automatically checks for a 'man' subdirectory associated with
    # each directory in PATH, so we don't need to do the equivalent
    # here.  And setting MANPATH at all overrides that automatically
    # generated search list; since MANPATH is initially unset, but
    # PATH isn't, setting MANPATH can actually *reduce* the set of
    # directories man will search.
}

add_bin_man_after () {
    postpend_if_dir PATH "$1/bin"
    postpend_if_dir INFOPATH "$1/info"
}  

add_library_path () {
    prepend_if_dir LD_LIBRARY_PATH "$1"
}