clojure.contrib.repl-ln available

[Stephen C. Gilardi]

I was just about to do that, Randall. :-)

clojure.contrib.repl-ln is a repl that supports lines and line
numbers. Here's a session that demonstrates it.

--Steve

% java -cp clojure.jar:clojure-contrib.jar clojure.main -e "(use
'clojure.contrib.repl-ln)" -e "(repl)"
1:1 user=> ; clojure.contrib.repl-ln provides a repl that supports
lines and line numbers in the input stream
1:2 user=> ; every input line is counted. Every input line that's not
within a clojure object generates a prompt
1:3 user=>
1:4 user=>
1:5 user=> ; even blank lines
1:6 user=> 1 2 3 ; multiple objects on one line are all printed, but
only produce one prompt
1
2
3
1:7 user=> jkl ; exceptions show the repl name and line number where
they happened
java.lang.Exception: Unable to resolve symbol: jkl in this context
(repl-1:7)
1:8 user=> (/ 1 0)
java.lang.ArithmeticException: Divide by zero (repl-1:8)
1:9 user=> (defn greet [] "
hello"
)
#'user/greet
1:12 user=> (meta (var greet)) ; metadata for definitions include repl
name and line number
{:file "repl-1", :line 9, :ns #<Namespace user>, :name
greet, :arglists ([])}
1:13 user=> ; the repl name is configurable. It defaults to: "repl-%S"
where %S is the repl serial number
1:14 user=> (repl) ; creating a new repl produces a nested repl with a
new serial number
2:1 user=> ; and a fresh set of line numbers
2:2 user=> ; the default prompt is "%S:%L %N=> ", serial number, line
number, and namespace name
2:3 user=> (in-ns 'cool)
#<Namespace cool>
2:4 cool=> ; quitting a repl pops namespace as well
2:5 cool=> ^D
nil
1:15 user=> (repl) ; creating a new repl produces a nested repl with a
new serial number
3:1 user=> ; if the prompt is too busy for your taste, you can set it
to something more familar:
3:2 user=> (set-repl-prompt "%N=> ")
nil
user=> (repl) ; nested repls inherit their name format and prompt
format from their parent
user=> ; this one is serial number 4, but if it's not in the prompt,
how can we know?
user=> (repl-info) ; repls have properties accessible this way
{:name "repl-4", :started #<Date Wed Dec 03 09:02:59 EST 2008>, :name-
fmt "repl-%S", :prompt-fmt "%N=> ", :serial 4, :thread 1, :depth
3, :line 2}
user=> (print-repl-info) ; or this way
Name: repl-4
Started: Wed Dec 03 09:02:59 EST 2008
Name-fmt: "repl-%S"
Prompt-fmt: "%N=> "
Serial: 4
Thread: 1
Depth: 3
Line: 3
nil
user=> ; thread id and nesting level are also available for use in the
prompt and repl name.
user=> ; a long running clojure could create many of them, say, over
sockets.
user=> (set-repl-prompt "%S:%T:%D:%L %N=> ") ; a big ol' prompt
nil
4:1:3:7 user=>
4:1:3:8 user=>
4:1:3:9 user=>
4:1:3:10 user=> (set-repl-name "clojure-%S:%T:%D")
nil
4:1:3:11 user=> kjd
java.lang.Exception: Unable to resolve symbol: kjd in this context
(clojure-4:1:3:11)
4:1:3:12 user=> ; end-of-stream (^D at the beginning of the line on
Unix/Mac OS X) quits the repl
4:1:3:13 user=> ^D
nil
user=> ^D
nil
1:16 user=> ^D
%

[J. McConnell]

This looks awesome, great work Stephen!

[Randall R Schulz]

On Wednesday 03 December 2008 06:27, Stephen C. Gilardi wrote:
> I was just about to do that, Randall. :-)

Yeah, I'm both nosey and impatient...

> clojure.contrib.repl-ln is a repl that supports lines and line
> numbers. Here's a session that demonstrates it.

Thanks. That looks pretty cool. Do I understand from your example that
if I just hit return I get another prompt? I've been meaning to ask for
that.

I'm curious how it interacts with rlwrap in general?

Also, does anybody know how gain any degree or kind of control over
signal handling in Java? Preferably pure Java, but since everything I do
is on Linux, a native-code solution for that platform would be
acceptable.

Rlwrap is quite nice, but aside from handling, say SIGINT (CTRL-C) for
its own purposes, it then passes that on to the wrapped program, and
that ends up just killing the JVM.

Anyway, this happened:

user=> (use 'clojure.contrib.repl-ln)
java.lang.IllegalArgumentException: No matching method: repl (repl_ln.clj:213)

The Clojure invocation I used was:

% java -cp /repo/JT/clojure-svn/clojure/clojure.jar:/repo/JT/clojure-svn/clojure-contrib/trunk/src:... \
clojure.lang.Repl

I'm running Clojure SVN 1141 on java version "1.6.0_10-rc2".

> --Steve

Randall Schulz

[Stephen C. Gilardi]

On Dec 3, 2008, at 10:06 AM, Randall R Schulz wrote:

Thanks. That looks pretty cool. Do I understand from your example that
if I just hit return I get another prompt? I've been meaning to ask for
that.

Thanks and yes, that's right.

I'm curious how it interacts with rlwrap in general?

I haven't tried it.

Anyway, this happened:

user=> (use 'clojure.contrib.repl-ln)
java.lang.IllegalArgumentException: No matching method: repl (repl_ln.clj:213)


The Clojure invocation I used was:

% java -cp /repo/JT/clojure-svn/clojure/clojure.jar:/repo/JT/clojure-svn/clojure-contrib/trunk/src:... \
   clojure.lang.Repl

clojure.contrib.repl-ln was missing a ":require" of clojure.main. It never showed up for me because I always launch with that as the main class these days.

Fixed. Thanks for the detailed report!

--Steve

[Drew Olson]

Would it make sense to add a :gen-class declaration and have the -main function automatically call the repl function? This would make launching the repl less painful for new-comers.

- Drew

On Wed, Dec 3, 2008 at 9:27 AM, Stephen C. Gilardi <sque...@mac.com> wrote:

[Randall R Schulz]

On Wednesday 03 December 2008 07:37, Stephen C. Gilardi wrote:
> ...

>
> Fixed. Thanks for the detailed report!

Detailed, eh?

Anyway, that did it and I gotta' say, very cool. And so far it seems
there's no adverse interaction with rlwrap. I've modified my Clojure
launcher script to have an option for easy launching with this REPL.

Thanks again.

> --Steve

Randall Schulz

[Dudley Flanders]

On Dec 3, 2008, at 9:06 AM, Randall R Schulz wrote:
>
> Also, does anybody know how gain any degree or kind of control over
> signal handling in Java? Preferably pure Java, but since everything
> I do
> is on Linux, a native-code solution for that platform would be
> acceptable.

Not in a portable way, but if you're running a Sun JDK, there's
sun.misc.Signal and sun.misc.SignalHandler.

:dudley

[Randall R Schulz]

Good information. Thanks.

Perhaps Steve would consider applying them to making his fancy REPL more
robust for terminal users?

> :dudley

Randall Schulz

[Dakshinamurthy Karra]

I am using jline with contrib.repl and it is working pretty well. I
use this command:

java -classpath
.:./jline-0.9.93.jar:classes:clojure/clojure.jar:clojure-contrib/clojure-contrib.jar
jline.ConsoleRunner clojure.main -e "(use 'clojure.contrib.repl-ln)"
-e "(repl)"

-- KD

Dakshinamurthy Karra
(blog: http://blog.marathontesting.com)
(daily dose: http://twitter.com/marathontesting)

[Stephen C. Gilardi]

On Dec 3, 2008, at 9:32 AM, Drew Olson wrote:

Would it make sense to add a :gen-class declaration and have the -main function automatically call the repl function? This would make launching the repl less painful for new-comers.

- Drew

It is a good idea and I'll work on it. What I do at the moment is have a small script that does what the "-e" commands do in my post. I give the path to that script as an argument to clojure.main.

--Steve

[Randall R Schulz]

On Wednesday 03 December 2008 09:10, Dakshinamurthy Karra wrote:
> I am using jline with contrib.repl and it is working pretty well. I
> use this command:

I recently switched from JLine to rlwrap. I think the latter is
preferable, but I'm sure there are matters of taste involved.

> ...
>
> -- KD

Randall Schulz

[Meikel Brandmeyer]

Hi,

Am 03.12.2008 um 18:24 schrieb Stephen C. Gilardi:
>> Would it make sense to add a :gen-class declaration and have the
>> -main function automatically call the repl function? This would make
>> launching the repl less painful for new-comers.

> It is a good idea and I'll work on it. What I do at the moment is have
> a small script that does what the "-e" commands do in my post. I give
> the path to that script as an argument to clojure.main.

I tried to trace down, what happens before we enter the Repl.
The only points I noticed were setting the namespace to user
and setting the command-line-args. I wrote a simple main to
do this. Patch attached. To be started with clojure.contrib.repl_ln.
Note: _ instead of -.

Sincerely
Meikel

[Mark Volkmann]

I made the same switch. The big sell for me is support for vi
keystrokes in the REPL. I feel much more productive with rlwrap than
JLine.

--
R. Mark Volkmann
Object Computing, Inc.

[Stephen C. Gilardi]

On Dec 3, 2008, at 1:12 PM, Meikel Brandmeyer wrote:

I tried to trace down, what happens before we enter the Repl.
The only points I noticed were setting the namespace to user
and setting the command-line-args. I wrote a simple main to
do this. Patch attached. To be started with clojure.contrib.repl_ln.
Note: _ instead of -.

Patch applied. Thanks very much, Meikel!

--Steve

[Randall R Schulz]

There are other things. E.g., JLine gets confused after suspending the
REPL (using SIGTSTP / CTRL-Z) and it does not support completion or (a
personal favorite) CTRL+LEFT-ARROW and +RIGHT-ARROW. Rlwrap also has
incremental search (CTRL-R and SHIFT+CTRL-R).

The only real down-side of CTRL+ARROW is that I get in the habit of
using them (previously only in BASH) and then out of habit I type them
in Vim, which causes bad things to happen...

Randall Schulz

[Stephen C. Gilardi]

On Dec 3, 2008, at 11:39 AM, Randall R Schulz wrote:

Perhaps Steve would consider applying them to making his fancy REPL more 
robust for terminal users?

I like the idea. If someone would like to work out the basics and post some example code, I'll be happy to try to get it running in repl-ln.

--Steve

[Randall R Schulz]

Steve,

I'm not acquainted with this, since Dudley's reply was the first I'd
heard of sun.misc.Signal et. al.

However, with that in hand I found what looks like a pretty good
tutorial / how-to article:

- Google: Ringlord "POSIX Signal Handling in Java"
"POSIX Signal Handling in Java"
<http://ringlord.com/publications/jsignals-howto/jsignals.pdf>

> --Steve

Randall Schulz

[Randall R Schulz]

On Friday 05 December 2008 14:57, Randall R Schulz wrote:
> Steve,
>
> On Friday 05 December 2008 14:45, Stephen C. Gilardi wrote:
> > On Dec 3, 2008, at 11:39 AM, Randall R Schulz wrote:
> > > Perhaps Steve would consider applying them to making his fancy
> > > REPL more
> > > robust for terminal users?
> >
> > I like the idea. If someone would like to work out the basics and
> > post some example code, I'll be happy to try to get it running in
> > repl-ln.
>
> I'm not acquainted with this, since Dudley's reply was the first I'd
> heard of sun.misc.Signal et. al.

By the way, Sun excludes the sun.* packages from the JavaDoc HTML they
publish, so you'll have to generate it yourself or avail yourself of
whatever local tool / IDE / ingenuity you have to see the documentation
and / or source for these classes.

> However, with that in hand I found what looks like a pretty good
> tutorial / how-to article:
>
> - Google: Ringlord "POSIX Signal Handling in Java"
> "POSIX Signal Handling in Java"
> <http://ringlord.com/publications/jsignals-howto/jsignals.pdf>

RRS