Macaulay2 / Macaulay2/M2

Dispatching of lift and promote

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Core
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Macaulay2
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Merged PRs (30d)
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Description

`lift` and `promote` are defined here:
https://github.com/Macaulay2/M2/blob/65332ed07101a51255182fb5a16e4e6e20809292/M2/Macaulay2/m2/rings.m2#L74-L76
Later on, we have such a method installed:
https://github.com/Macaulay2/M2/blob/65332ed07101a51255182fb5a16e4e6e20809292/M2/Macaulay2/m2/modules.m2#L158-L163
Why is this defined this way, and not just `lift(Module, Ring)`? In particular, `Ring` is not in the ancestors of `RingElement`, so how does the dispatching work in this case? The [documentation](http://www2.macaulay2.com/Macaulay2/doc/Macaulay2-1.16/share/doc/Macaulay2/Macaulay2Doc/html/_method.html) is rather thin in this area.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with M2/Macaulay2/m2/rings.m2 at lines 74-76 and M2/Macaulay2/m2/modules.m2 at lines 158-163, then read the method-dispatch documentation linked in the issue. Trace how the installed lift method is selected for the relevant argument types. Done means explaining this dispatch behavior and identifying the documentation clarification needed.

Written by the indexing model from the issue text.

Assessment

Domain
documentation
Issue type
Documentation
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
45/100

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