Implement PEP 786: Precision and modulo-precision flag format specifiers for integer fields

[jb2170]

Feature or enhancement

Proposal:

Issue for PR to implement PEP 786 so I can link to this issue in blurb in the PR.

Has this already been discussed elsewhere?

Forum discussions:

• Pre-PEP discussion: https://discuss.python.org/t/implement-precision-format-spec-for-int-type-data/80760
• PEP discussion: https://discuss.python.org/t/pep-786-precision-and-modulo-precision-flag-format-specifiers-for-integer-fields/106907

Implementation discussions:

• Old implementation discussion, discarded. gh-74756: support precision field for integer formatting types #131926
• Some talk of modulo-precision: Add integer formatting code for fixed-width signed arithmetic (2's complement) #74756

Actual implementation:

• Reference implementation Issue: Implement PEP 786: Precision and modulo-precision flag format specifiers for integer fields #146436
• Reference implementation PR: gh-146436: Implementation of PEP 786 #146437

PEPs repo:

• Merged PR: PEP 786: Precision and Modulo-Precision Flag format specifiers for integer fields peps#4416
• Old PR with wrong branch name / PEP number, closed in favor of merged one: [Old] PEP 786: Precision and Modulo-Precision Flag format specifiers for integer fields peps#4365

Linked PRs

• gh-146436: Implementation of PEP 786 #146437

[jb2170]

Addressed by https://github.com/jb2170/cpython/tree/pep-786

I'll rebase soon.

[picnixz]

As I mentioned on the PR:

Can we avoid creating reference implementations on the main repo please? use a fork please. In addition, issues should be created once it's been discussed and accepted, not before.

[skirpichev]

I think, that pr might be kept, as a draft. It's already opened.

But lets close this issue. The PEP wasn't even discussed. We can reopen, if it will be accepted.

[gvanrossum]

@jb2170 A link to the Discourse thread would be appreciated.

[jb2170]

@jb2170 A link to the Discourse thread would be appreciated.

I've updated the OP to include the discussion thread 😄

Edit 2026/04/09: Added the new PEP discussion thread too