Just for fun: Can it be done shorter than this?

[Stephan Kuhagen]

Hello again to some fun comparison of other languages to my favourite one...

In comp.programming someone posted a nice one-liner in Perl to print only
the first appearance of any input line while preserving the order (most
times this is done by sorting and then using uniq-command, but that
destroys the original order). The line is:

perl -ne 'print $_ unless $seen{$_}++'

Nice one. - Someone else then replied with awk:

awk '!o[$0]++'

WOW! - But using the existence of an array variable and simultanously
setting it, reminded me of Tcls arrays, so I tried my best, to make it as
short as possible (and as nasty and unreadable as possible...):

while {0>[gets stdin l]?[exit]:1&[append o($l) 1]==1?"[puts $l]1":1} {}

Doesn't even look like Tcl, does it? But I can't get it shorter. Anyone out
there, who beats this? Just for fun...

Regards
Stephan

[suchenwi]

On 27 Feb., 12:58, Stephan Kuhagen <nos...@domain.tld> wrote:>
> while {0>[gets stdin l]?[exit]:1&[append o($l) 1]==1?"[puts $l]1":1} {}
>
> Doesn't even look like Tcl, does it? But I can't get it shorter. Anyone out
> there, who beats this? Just for fun...

I replaced [exit] with 0, and removed the redundant 1& :

while {0>[gets stdin l]?0:[append o($l) 1]==1?"[puts $l]1":1} {}

[suchenwi]

Another byte saved, by using the "anonymous array", and more
mysterious:

while {0>[gets stdin l]?0:[append ($l) 1]==1?"[puts $l]1":1} {}

[Stephan Kuhagen]

suchenwi wrote:

Damn... The exit was a relict of a previous try, 0 is of course much better.
But the anonymous array is really cool... ;-)

btw, two more bytes saved:

while {0>[gets stdin l]?0:[append ($l) 1]==1?"[puts $l]1":1} {}

Stephan

[Stephan Kuhagen]

Stephan Kuhagen wrote:

> while {0>[gets stdin l]?0:[append ($l) 1]==1?"[puts $l]1":1} {}

Of course, that's what you already posted. I think, I should read before
replying... ;-)

<mumble>must find shorter...</mumble>

Stephan

[Ronnie Brunner]

I know, totally unsexy, because readable, but still 3 bytes shorter:

while {[gets stdin l]>=0} {if {[append $l 1]==1} {puts $l}}

And if incr would actually auto-initialize a variable as proposed a
while ago here on c.l.t you could save another 4 bytes ;-)

while {[gets stdin l]>=0} {if {[incr $l]==1} {puts $l}}

Ronnie

[Stephan Kuhagen]

Ronnie Brunner wrote:

> suchenwi wrote:
>> Another byte saved, by using the "anonymous array", and more
>> mysterious:
>>
>> while {0>[gets stdin l]?0:[append ($l) 1]==1?"[puts $l]1":1} {}
>>

One byte shorter than this (this time really...):

while {0>[gets stdin l]?0:[append ($l) 1]<2?"[puts $l]1":1} {}

> I know, totally unsexy,

Not at all. The only "drawback" is, that it somehow feels longer because of
using both the condition and the command part of while.

> because readable, but still 3 bytes shorter:
>
> while {[gets stdin l]>=0} {if {[append $l 1]==1} {puts $l}}

And much more obvious!

> And if incr would actually auto-initialize a variable as proposed a
> while ago here on c.l.t you could save another 4 bytes ;-)
>
> while {[gets stdin l]>=0} {if {[incr $l]==1} {puts $l}}

Yes, I thought of this, too. Isn't auto-initialize for incr a TIP?

Stephan

[Stephan Kuhagen]

Ronnie Brunner wrote:

> I know, totally unsexy, because readable, but still 3 bytes shorter:
>
> while {[gets stdin l]>=0} {if {[append $l 1]==1} {puts $l}}

I just see, that you only can save one byte, because you have to use an
array variable. Otherwise a line containing e.g. tcl_platform would kill
the script.

Stephan

[Stephan Kuhagen]

Ronnie Brunner wrote:

> I know, totally unsexy, because readable, but still 3 bytes shorter:
>
> while {[gets stdin l]>=0} {if {[append $l 1]==1} {puts $l}}

Sorry... Saving one more byte from yours:

while {[gets stdin l]+1} {if {[append $(l) 1]==1} {puts $l}}

Stephan

[Georgios Petasis]

O/H Stephan Kuhagen έγραψε:

And if we put unknown into play, we can abbreviate commands :-)

wh {[ge stdin l]+1} {if {[ap $l 1]==1} {pu $l}}

George

[Glenn Jackman]

At 2007-02-27 08:52AM, "Ronnie Brunner" wrote:
> suchenwi wrote:
> > Another byte saved, by using the "anonymous array", and more
> > mysterious:
> >
> > while {0>[gets stdin l]?0:[append ($l) 1]==1?"[puts $l]1":1} {}
> >
>
> I know, totally unsexy, because readable, but still 3 bytes shorter:
>
> while {[gets stdin l]>=0} {if {[append $l 1]==1} {puts $l}}

we can drop the braces in the if condition here:

while {[gets stdin l]>=0} {if [append ($l) 1]==1 {puts $l}}

You need the parentheses around "$l" in the append command -- otherwise
it breaks if you have a line with a single "l"

Or, using http://wiki.tcl.tk/17599
tcl.tcl -n -e 'if [append ($l) 1]==1 {puts $l}'

Compared to the original example:

perl -ne 'print $_ unless $seen{$_}++'

--
Glenn Jackman
"You can only be young once. But you can always be immature." -- Dave Barry

[Uwe Klein]

package require 1liners
42

uwe

[suchenwi]

On 27 Feb., 16:06, Glenn Jackman <gle...@ncf.ca> wrote:
> You need the parentheses around "$l" in the append command -- otherwise
> it breaks if you have a line with a single "l"

The parentheses are there to make sure the lines are dumped into the
"anonymous array" as keys, where the values are a string of 1s, one
for each occurrence.

[Donal K. Fellows]

Georgios Petasis wrote:
> And if we put unknown into play, we can abbreviate commands :-)
>
> wh {[ge stdin l]+1} {if {[ap $l 1]==1} {pu $l}}

Let's avoid such things for now, since adding code to make the minimal
code work as a script takes the overall length up. My shortest so far
is this:
while {[gets stdin l]+1} {if [incr ($l)]==1 {puts $l}}
It does require 8.5 for auto-increment; without that, you have to use
[append] and that makes the code several characters longer.

The startling thing is how close to good style the shortest version
seems to be. :-)

Donal.

[Stephan Kuhagen]

Uwe Klein wrote:

> package require 1liners

Excellent! Will this be already in 8.5 or do we have to wait for 9.0?

Thanks people, you've made my day...
Stephan

[Stephan Kuhagen]

Donal K. Fellows wrote:

> The startling thing is how close to good style the shortest version
> seems to be. :-)

Yes, this is the only thing, which totally disappoints me here. It is short
as it can get, AND its readable (even if you don't know Tcl very well). The
Perl-Guys will never respect Tcl'ers... ;-)

Stephan

[Stephan Kuhagen]

Glenn Jackman wrote:

> Or, using http://wiki.tcl.tk/17599
> tcl.tcl -n -e 'if [append ($l) 1]==1 {puts $l}'

Yes, but where do you get the lines from stdin from...?

Nevertheless, I like the idea of having a "-e"-switch to tclsh, as many
other shells, not only Perl, have. Myself and many other Tcl'ers seem to
have written a wrapper script for that purpose, to be able to write
something like:

tcl 'puts "hello world"'

Would be nice, if tclsh had such an option.

Stephan

[Ronnie Brunner]

I don't think you need an array. Omitting the ( ) just creates scalar
variables, which isn't all that bad (unless you plan to use the
interpreter for other stuff too ;-). However the single 'l' line would
break the script as Glen correctly points out.

A compromise would be to use (on Donal's unabbreviated short version)

while {[gets stdin l]+1} {if [incr f$l]==1 {puts $l}}

This save one byte of the parenthesis, but prefixes all used variables
with an 'f' (could be any other character, but the 'l' which then would
clash with the l variable used for the line in the case of an empty line.

However, not as beautiful as with (), because an arbitrary character is
introduced and it's less readable.

Ronnie

[Stephan Kuhagen]

Ronnie Brunner wrote:

> I don't think you need an array.

You do. Try your version (

while {[gets stdin l]+1} {if [append $l 1]==1 {puts $l}}

) with an input like this

one
one
two
tcl_platform
three
three

The line containing tcl_platform kills the script, because tcl_platform is a
pre-defined array variable, where you cannot append to.

> A compromise would be to use (on Donal's unabbreviated short version)
>
> while {[gets stdin l]+1} {if [incr f$l]==1 {puts $l}}
>
> This save one byte of the parenthesis, but prefixes all used variables
> with an 'f' (could be any other character, but the 'l' which then would
> clash with the l variable used for the line in the case of an empty line.
>
> However, not as beautiful as with (), because an arbitrary character is
> introduced and it's less readable.

Yes, it works, but will fail when used in conjunction with other code which
contains an array variable starting with f and the contents of one input
line. Okay, that's very unlikely and if one uses obscure oneliners in
combination with clean code in a script somehow did not understand
the "spirit" of oneliners...

Stephan

[Andreas Leitgeb]

Donal K. Fellows <donal.k...@man.ac.uk> wrote:
> My shortest so far is this:
> while {[gets stdin l]+1} {if [incr ($l)]==1 {puts $l}}

while {[gets stdin l]+1} {if [incr ($l)]<2 {puts $l}}

And again one char saved.

> It does require 8.5 for auto-increment; without that, you have to use
> [append] and that makes the code several characters longer.

I want to make it absolutely clear, that this was
not my motivation for the auto-init-incr TIP. :-)

[Stephan Kuhagen]

Andreas Leitgeb wrote:

> while {[gets stdin l]+1} {if [incr ($l)]<2 {puts $l}}
>
> And again one char saved.

while {~[gets stdin l]} {if [incr ($l)]<2 {puts $l}}

And another one... ;-)

I wonder, if this oneliner will disappear at last and do its job by quantum
mind reading only...

Stephan

[Bruce Hartweg]

if your going to add a character - you should pick
an ugly one like @ or % or ^ or & or * or ! or ~
that way you can confuse people into thinking tcl has magic
behavior and they'll wonder what @$l means ;)

while {[gets stdin l]+1} {if [incr %$l]<2 {puts $l}}

Bruce

[Stephan Kuhagen]

> if your going to add a character - you should pick
> an ugly one like @ or % or ^ or & or * or ! or ~
> that way you can confuse people into thinking tcl has magic
> behavior and they'll wonder what @$l means ;)
>
>
> while {[gets stdin l]+1} {if [incr %$l]<2 {puts $l}}

Good idea, get some respect from Perl-People... I replaced l with _:

while {~[gets stdin _]} {if [incr ($_)]<2 {puts $_}}

Stephan

[Andreas Leitgeb]

Bruce Hartweg <doNO...@nowhere.com> wrote:
> while {[gets stdin l]+1} {if [incr %$l]<2 {puts $l}}

This prefix version isn't good. try with this input:

hello
hello(foo)

gotta stick to parens.

Apropos sticking to parens:
just a single open paren as a prefix might actually work!

while {~[gets stdin _]} {if [incr ($_]<2 puts\ \$_}

(replacing the braces for the "then" block with backslashing
space and dollar doesn't reduce size, but readability :-)

[Donal K. Fellows]

Stephan Kuhagen wrote:
> I wonder, if this oneliner will disappear at last and do its job by quantum
> mind reading only...

Oh, you mean like this:
rmmadwim -nocomplain

Donal.

[Stephan Kuhagen]

Donal K. Fellows wrote:

Isn't "-nocomplain" the option for glob not to say anything, if nothing is
found, i.e. no mind...? Hey! ;-)

Stephan

[Donal K. Fellows]

Andreas Leitgeb wrote:
> Apropos sticking to parens:
> just a single open paren as a prefix might actually work!

No, it won't. Consider the input:
hello
hello)
You cannot construct a scalar variable whose name contains an open
paren and ends with a close paren. You can also get into trouble
with :: in the string, such as:
not_a_namespace::fubar

Donal.

[Donal K. Fellows]

Stephan Kuhagen wrote:
> Isn't "-nocomplain" the option for glob not to say anything, if nothing is
> found, i.e. no mind...? Hey! ;-)

I actually think of it meaning not to complain at what it finds in the
mind, but if the cap fits... :-)

Donal.

[Andreas Leitgeb]

Donal K. Fellows <donal.k...@man.ac.uk> wrote:

> Andreas Leitgeb wrote:
>> Apropos sticking to parens:
>> just a single open paren as a prefix might actually work!
> No, it won't. Consider the input:
> hello
> hello)

Actually, it looks just like this is no problem:
set (abc 42; set (abc ;# -> 42
set (abc) 43; set (abc) ;# -> 43

So, some of the stuff created will be local variables, the rest
will be keys for the empty-named array, but all is distinguishable.

> You can also get into trouble with :: in the string, such as:
> not_a_namespace::fubar

This is unfortunately correct.
set (a::b 42 ;# -> can't set "(a::b": parent namespace doesn't exist

damn. :-/
shan't we autocreate namespaces... (NOT!)

[Matthias Kraft]

Stephan Kuhagen wrote:
> tcl 'puts "hello world"'
>
> Would be nice, if tclsh had such an option.

Well, do it the other way around:

echo 'puts "hello world"' | tclsh

kind regards
--
Matthias Kraft
Software AG, Germany

(They that can give up essential liberty to obtain a little temporary)
(safety deserve neither liberty nor safety. -- Benjamin Franklin)

[Andreas Leitgeb]

Matthias Kraft <Matthia...@nospam.softwareag.com> wrote:
> Stephan Kuhagen wrote:
>> tcl 'puts "hello world"'
>> Would be nice, if tclsh had such an option.
> Well, do it the other way around:
> echo 'puts "hello world"' | tclsh
> kind regards

This works just as long as the script is not meant to read data from
stdin itself.