Re: Floating point print Incompatibility SWI 5.10.2 versus 6.6.2

On 21/03/2014, at 11:56 PM, Jan Wielemaker wrote:
> All debugging is traditionally printed using print/1, which traditionally uses unquoted write + portray.

I believe I've seen a Prolog system that had
printq/1, which was the obvious hybrid between
print/1 and writeq/1.

SWI Prolog already has the write_term/2 option
portray_goal, something other Prologs would do
well to pick up.

>  I've proposed
> a while ago to change this to be quoted write + portray.

Why does print/1 exist?

Because Chris Mellish was trying to debug a program
computing semantics for English where each goal filled
more than one screen if written in full.

print/1 was introduced so that you could *abbreviate*
the debugging output of your program heavily.  This
idea of diligently protecting every little detail with
quotation marks while simultaneously hiding >90% of
everything didn't really make much sense.  The output
was never intended to be valid Prolog syntax.

Most of the time when you are debugging, you'd like
floating point numbers to be abbreviated heavily, to
just a couple of digits.  Anything more would be
clutter, getting in the way of seeing what you need to
see.  But sometimes it is floating point code that you
are debugging, and you need to see all the digits.

It might be interesting to find out what people are
using print/1 for.  There might be conflicting use
cases that would be better served by more/different
options.