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Improve repr() of AST nodes #116022
Description
Feature or enhancement
Proposal:
I often use ast.parse in the terminal to explore what the AST looks like:
>>> ast.parse("x = 3")
<ast.Module object at 0x105450b50>
But I have to remember to use ast.dump() to get useful output:
>>> ast.dump(ast.parse("x = 3"))
"Module(body=[Assign(targets=[Name(id='x', ctx=Store())], value=Constant(value=3))], type_ignores=[])"
It would be nice if the default repr() of AST nodes was more like the output of ast.dump(), so it's easier to see at a glance how it works.
One concern would be around the size of the output:
>>> from pathlib import Path
>>> import typing
>>> typing_py = Path(typing.__file__).read_text()
>>> len(ast.dump(ast.parse(typing_py)))
304244
As a middle ground, we could limit the depth of the AST provided in the repr(), e.g. to 2 levels, and also the number of list elements provided.
The repr() of a module's AST might then look something like:
Module(body=[Expr(value=Constant(...)), ..., Assign(targets=[Name(...)], value=Constant(...))], type_ignores=[])
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
Activity
tomasr8 commentedon Mar 10, 2024
This is something that would be useful for me as well since I also sometimes poke around the AST 😄
Were you planning to implement this yourself or do you think I could give it a try? Looking at the code, it'll probably have to be implemented in C since that's where the base AST type is defined.
JelleZijlstra commentedon Mar 10, 2024
I will do it eventually if no one else gets to it but haven't started yet. You're welcome to start working on it! This might need changes to
asdl_c.pywhich is the Python code that generates the C code for the AST.gh-116022: Improve `repr()` of AST nodes (#117046)
pythongh-116022: Improve `repr()` of AST nodes (python#117046)