PEP 812: Imaginary type and IEC 60559-compatible complex arithmetic

[skirpichev]

Basic requirements (all PEP Types)

• Read and followed PEP 1 & PEP 12
• File created from the latest PEP template
• PEP has next available number, & set in filename (pep-NNNN.rst), PR title (PEP 123: <Title of PEP>) and PEP header
• Title clearly, accurately and concisely describes the content in 79 characters or less
• Core dev/PEP editor listed as Author or Sponsor, and formally confirmed their approval
• Author, Status (Draft), Type and Created headers filled out correctly
• PEP-Delegate, Topic, Requires and Replaces headers completed if appropriate
• Required sections included
  • Abstract (first section)
  • Copyright (last section; exact wording from template required)
• Code is well-formatted (PEP 7/PEP 8) and is in code blocks, with the right lexer names if non-Python
• PEP builds with no warnings, pre-commit checks pass and content displays as intended in the rendered HTML
• Authors/sponsor added to .github/CODEOWNERS for the PEP

Standards Track requirements

• PEP topic discussed in a suitable venue with general agreement that a PEP is appropriate
• Suggested sections included (unless not applicable)
  • Motivation
  • Rationale
  • Specification
  • Backwards Compatibility
  • Security Implications
  • How to Teach This
  • Reference Implementation
  • Rejected Ideas
  • Open Issues
• Python-Version set to valid (pre-beta) future Python version, if relevant
• Any project stated in the PEP as supporting/endorsing/benefiting from the PEP formally confirmed such
• Right before or after initial merging, PEP discussion thread created and linked to in Discussions-To and Post-History

---

📚 Documentation preview 📚: https://pep-previews--4681.org.readthedocs.build/

https://pep-previews--4681.org.readthedocs.build/pep-0812/

[skirpichev]

Based on feedback from the latest discussion thread, I hope @serhiy-storchaka might sponsor this.

CC @serhiy-storchaka
CC @mdickinson

(Alternative formatting with mathjax)

N.B. I did local builds with the default sphinx config and it seems, that "math" directives are rendered odd with the "maths_to_html". In particular, equation numbering is lost (though, references to equations are kept). Any way to fixing this without replacing "math" with something else? CC @AA-Turner
Locally I've something like this:

[hugovk]

Please review PEP 1.

The general order of things:

1. Open a discussion to see if there is consensus for this idea. This is also to save you time in case the idea is rejected.
2. During the discussion, find a sponsor.
3. Work with your sponsor, and when they think the PEP is ready for submission, then open the PR.
4. A PEP number is assigned by a PEP editor after the sponsor has confirmed their sponsorship.

Therefore please don't write and submit a PEP with just a hope someone will sponsor. This should be arranged beforehand.

[hugovk]

@hugovk, may I reserve some number and set CODEOWNERS?

Yes, you may use 812. Thanks!

[hugovk]

Mostly grammar nits.

[skirpichev]

@serhiy-storchaka, I hope now this ready for your review.

Perhaps, the major remaining question is: should we try to introduce the imaginary builtin from beginning? Current version don't do so (it's in Open Issues), but maybe this should be reverted? If we introduce a new builtin - this PEP can discuss parsing of strings, which it will accept.

[skirpichev]

@serhiy-storchaka, have you changed your mind on support of this PEP?

If not, what's left here to do?