Use aprint when displaying value

Question

Problem: when trace-ns is used, very long displays in the output stream is very hard to read when the fn calls are important and with voluminous data structure
Solution: Use (link: https://github.com/razum2um/aprint text: Aprint library) when printing value in the output string, now get syntax hightlighting and better layout of data structure
Tradeoffs: add a new dependency to tools.trace
Tests: yes, modify the cleanup fn to also clean the color information added by aprint, so 100% tests passed

Answer 1

Comment made by: jafingerhut

Jeremie, I am not certain, but I believe it is a policy of Clojure contrib libraries not to depend on libraries other than those in Clojure or Clojure contrib.

Perhaps if new arities were added to some existing tools.trace functions or macros, sprint or any other developer-desired function could be provided as arguments to control how printing occurs?

Answer 2

Comment made by: jgrodziski

Hi Andy,

Thanks for your comment, yes I thought about that and known it would be the greatest concern...
I'll have a look at 2 possibilities:
- the fastest: add new arg to tools.trace fns and macros for providing a filter that can add the colors and layout
- the better: see if inlining the aprint code is worth considering, or better add the syntax hightlighting feature in clojure.pprint even though pprint is not used in tools.trace (and along with some neat library like (link: https://github.com/AvisoNovate/pretty text: Pretty) that could be added to clojure.repl)

In the end, adding aprint (both for color and layout) made a HUGE difference for me in usability...

Answer 3

Comment made by: alexmiller

Andy, that is not a policy afaik, merely a preference to minimize them as much as possible. There are other contribs that have external dependencies. It's up to Luc as the contrib lead whether he thinks this is ok here.

Answer 4

Comment made by: lprefontaine

I've looked into this. 'Inlining aprint' in tools.trace would be my first choice.
However we need to get Vlad Bokov to fill a CA (I do not see him in the list of contributors)
and to grant us the rights to include part of is source code in tools.trace.

Being a regular user of this tool, I find the arity avenue painful. It happens that we use this in
integrated test mode to nail issues. Then the output goes to a file were tty ansi commands
are not welcomed.

I think we need a mode state to enable/disable this feature. In the repl you would need a single
statement to get the colored output whatever trace fns you are calling. That can be part of your
user profile.

Eventually this could migrate to core.pprint but that will require some time before it ends up in a clojure release.

Meanwhile we can keep this isolated in tools.trace so it can be moved later elsewhere.

Comments ?

Answer 5

Comment made by: lprefontaine

I sent an email to Vlad and the url to this ticket.
Will have a discussion off line first and then move along with the plan if we can.

Answer 6

_Comment made by: razum2um_

Hi Jérémie, Alex and Luc,

I'm the author of aprint and really happy about you like my lib :)
Here are my thoughts about it:

1) I really like the idea to push it into tools.trace
2) Currently all the clojure contrib-libs have same patch acceptance policy as the lang, which I already wondered about https://github.com/clojure/clojure/pull/17#issuecomment-53628365 Try to understand, if a lib depends on another, the last one must share the same policy as the original, which is not the case, as I hardly stop accepting pull requests.
3) If you couldn't change this policy, I see "inlining" as best choice.

Now some points about the question "what will get inlined?"

4) I'm a bit surprised, that people don't share my intent to integrate it with repl like this https://github.com/greglook/whidbey, don't like colors, they simply like the layout. So coloring could be thrown away and we eliminate dependance on clansi. Or I could inline clansi (has MIT license), document a :^dynamic to turn on colors (which will get off by default)
5) Code for compact layout depends on jline and it's definitely won't get inside :) As such this will remain pprint/*print-right-margin* default value, which is 72 by default and isn't best choice in my opinion, but let it be. (or do you still run clojure on very old terminals?)
6) I don't see sense in introducing a new one :^dynamic for it, I suggest to rely on pprint/*print-pretty* and if it's true - use compact layout instead of pprint's default one

As such:
- i could fill and sign a CA
- prepare a dependent free patch for you, which includes only compact layout (and colors if you like) controlled by pprint/*print-pretty* and pprint/*print-right-margin*

Answer 7

Comment made by: lprefontaine

Hi Vlad,

any change on this one ?

I am about to issue 0.7.9. Dunno if you had some time to do the above steps.

Luc P.

Answer 8

Comment made by: lprefontaine

BTWY,

I still punch Clojure code on Hollerith cards so I am in unfamiliar territory when a line
exceeds 80 characters and the last 8 columns are not usable anyway :)

Answer 9

Reference: https://clojure.atlassian.net/browse/TTRACE-9 (reported by alex+import)