Missing de facto standard format/2-3 predicates

Would be possible to add the de facto standard format/2-3 predicates? Any (relatively) easy way for lifting the required functionality from an existing JS library?

For sample calls and tests, please see: https://github.com/LogtalkDotOrg/logtalk3/blob/master/tests/prolog/predicates/format_2/tests.lgt https://github.com/LogtalkDotOrg/logtalk3/blob/master/tests/prolog/predicates/format_3/tests.lgt

[jariazavalverde]

The default value for double_quotes in Tau Prolog is codes. The ISO/IEC 13211-1 leaves the default value to the implementation, so I relied on the default value of SWI (that now is string) and GNU Prolog. But the decision was totally arbitrary, I would have no problem changing it.

[triska]

Thank you very much for your interest! format.pl is available from:

https://github.com/mthom/scryer-prolog/blob/master/src/lib/format.pl

It would be awesome if you could integrate it in Tau Prolog too, this is a great opportunity for collaboration between two Prolog systems that are very conforming to the ISO standard and hence allow easy porting of applications and libraries. It is especially fortunate that both systems have taken the bold step to set double_quotes to chars by default, a setting which I strongly encourage and which format.pl also assumes.

If possible, please make the non-terminal format_//2 from this library also available in Tau Prolog: I have found format_//2 to be a really useful building block to format lists of characters, and to declaratively describe output so that it can actually be reasoned about in test cases instead of appearing only on the screen.

The library also provides listing/1 and portray_clause/1, which I hope you also find useful for Tau Prolog. I often use portray_clause/1 when emitting solutions to generate output that can later be read with read/1 for convenient testing and reasoning.

Please let me know if you need anything specific to use the library: Ideally, porting it should amount to maybe changing a few directives, and changing the two occurrences of “Scryer” to “Tau”.