Subject: bug#17657: pretty-print #:width values above 49 don't work?

From: Mark H Weaver <[email-masked]>
Date: Sun, 01 Jun 2014 14:40:56 -0400

Mark Polesky <[email-masked]> writes:
> Neither example below should be line-wrapped, but the second one 
> is.

Our pretty printer, inherited from SLIB and originally written by Marc
Feeley, uses a great many heuristics to make formatting decisions.
These heuristics are undocumented and subject to change.

One of its heuristics is that individual expressions shall not be more
than 49 columns wide.  Notice that pretty-print.scm includes the
following internal definition:

  (define max-expr-width 50)

(although in fact the maximum width ends up being 49)

> Is there a workaround?

A couple of years ago I added an undocumented #:max-expr-width keyword
argument to pretty-print, in order to improve the formatting of
psyntax-pp.scm.  You could use that.

It would be good to redesign and rewrite our pretty-printer from scratch
at some point.

> $ guile --version
> Guile 1.8.8

We no longer support Guile 1.8.x.  You should transition to 2.0.

     Thanks,
       Mark