1) I don't know what "XP-style" means.  It needs a reference.

2) For "machine-readable output" read "output readable by `read`.

3) By convention, angle brackets are used around macro arguments, not
procedure arguments, in synopses.

4) I am inclined to think that there should be no level that doesn't
provide guarantees for shared and circular references.  One problem is
that this sacrifices re-readability on Schemes that don't have #n= and
#n# lexical syntax.  This would also mean that higher levels of
support wouldn't work on systems (especially R6RS ones) without such
syntax. This question is orthogonal to support levels

5) You should mention the ability to request hex floats on systems
that support them.

6) The reason for the "#" stubs is that no reasonable Lisp supports
"#)" as lexical syntax.  This is not true of "...", although more than
one dot is an invalid identifier in CL (see 2.3.3 at
https://www.lispworks.com/documentation/HyperSpec/Body/02_cc.htm).  If
you are going to suggest something, "###" would be safer.

7) I think the advanced, fancy, and colorize libraries should be
postponed to a future SRFI.  Having them here rather undermines the
rationale for something much simpler than CL.

8) The measure library should IMO be defined with reference to UAX #11
East Asian Width at https://www.unicode.org/reports/tr11. This is much
better defined than wcwidth, which is entirely
implementation-dependent.  The data file for this spec is at
https://www.unicode.org/Public/UCD/latest/ucd/EastAsianWidth.txt.

On Thu, May 14, 2026 at 12:08 AM Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:
>
> Scheme Request for Implementation 272,
> "Pretty Printing",
> by Sergei Egorov,
> is now available for discussion.
>
> Its draft and an archive of the ongoing discussion are available at https://srfi.schemers.org/srfi-272/.
>
> You can join the discussion of the draft by filling out the subscription form on that page.
>
> You can contribute a message to the discussion by sending it to xxxxxx@srfi.schemers.org.
>
> Here's the abstract:
>
> This SRFI follows the traditional Scheme model of pretty printing, which treats it as a process distinct from general controlled formatting. While general-purpose formatters often prioritize specialized presentation at the expense of machine-readability, Scheme’s pretty-printers (such as those of SLIB and MIT Scheme) have traditionally treated pretty printing as a variant of write, differing primarily in the insertion of whitespace to make the presentation more palatable to humans. Common Lisp’s pretty-printer, by contrast, fills two roles simultaneously by integrating pretty printing with both its format facility and its generalized write procedures. This unified approach offers great power, but at the cost of complexity that can make it difficult to use effectively. We propose a specialized, layered approach, specifying five libraries of increasing functionality, where all but the first are optional. The libraries are downward-compatible: more powerful libraries satisfy all requirements of the simpler ones while adding new features. Implementors may choose to support a maximum level of functionality appropriate for their systems. Integration with monadic and string-based formatting libraries is supported.
>
> Regards,
>
> SRFI Editor