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* Something for the FAQ ?
@ 1993-09-14  9:56 gjv%atlas%cesar
  0 siblings, 0 replies; only message in thread
From: gjv%atlas%cesar @ 1993-09-14  9:56 UTC (permalink / raw)
  To: rc%hawkwind.utcs.toronto.edu%m_internet%m_mailnow%hermes.DECnet

Hello all,

I was just wondering, is there a collection of useful functions somewhere?
I found some in the FAQ and in the mail list archive of course, but I
assume that there are a lot more useful things out there, which could
be made more accessible when added to the FAQ for example. What made me
think of this is the following:

I'm using the prompt function for the initialisation of interactive
subshells, but this makes $status unusable if you aren't careful.
I came up with the following, which seems to work nicely. (init
is a function to initialise the subshell).

fn prompt  {
    s=$status {
        if ( ! ~ $ipid $pid ) {

            # one time call to init_shell(), initialises interactive subshell
        return $s

You can't simply save&restore $status, since the assignment to $status
itself would change the status.

I also wrote the next functions in order to be able
to clean up my $path (removing duplicates), or to remove an entry.

# remove(varname, elt) removes elt from $varname
fn remove {
    vn=$1 e=$2  o=() *=$$vn{
        while( ! ~ $#* 0)
           ~ $*(1) $e || o=($o $*(1) )

# clean(varname) removes all double entries from $varname, keeping the first
fn clean {
    vn=$1 o=() *=$$vn{
        while( ! ~ $#* 0)
            ~ $o $*(1) || o=($o $*(1) )

# example
clean path
remove path /usr/bin

The only thing to add is the support for ':' separated lists,
list-equivalent like PATH/path.

Thought it might be useful to have this kind of stuff in a place where
it can easily be found, like the FAQ for example.


J.G. Vons   E-Mail: vons@cesar.crbca1.sinet.slb.com

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