Intern string representation of operators and some other symbolic literals

Feature or enhancement

Proposal:

Python currently interns certain strings, such as keywords and some ASCII/Unicode characters, as well as module-specific strings. I propose extending this interning mechanism to the string representations of operators (e.g., "+=", "==", "|=").

Rationale:
Interning these strings could improve performance, particularly in code parsing workflows, by:

• Reducing memory overhead for repeated operator strings.
• Accelerating string comparisons (e.g., during AST construction or bytecode generation).

Target Symbols:
The following multi-character syntactic literals (with len() > 1) are candidates for interning:

# Syntax literals  
'...', '->' 

# Operators  
'**', '//', '==', '!=', '>=', '<=', ':=',  
'+=', '-=', '*=', '/=', '//=', '%=', '**=',  
'<<', '>>', '<<=', '>>=', '&=', '|=', '^='  

# And maybe character sequence that used in REPL?
'>>>'

Considerations:

• The change would be low-risk, as it targets immutable, statically known strings.
• The impact on startup time and memory usage should be negligible, given the small set of operators.

Would this be a worthwhile optimization for CPython? I’d appreciate feedback on the idea and the PoC.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-140235
• gh-151838

先审阅该提案以及链接的 PR gh-140235 和 gh-151838，重点关注其中提到的 parser、AST 构建、bytecode 生成和 REPL 用例。该 issue 没有定义已确定的实现方案或验收标准；在认为工作完成之前，请根据这些讨论确认预期的范围和结果。