support unparse for Suite ast

[thautwarm]

BPO	35632
Nosy	@pablogsal, @thautwarm, @isidentical

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2020-03-04.18:25:34.150>
created_at = <Date 2019-01-01.18:02:50.361>
labels = ['invalid', 'type-feature', 'library', '3.9']
title = 'support unparse for Suite ast'
updated_at = <Date 2020-03-04.18:25:34.149>
user = 'https://github.com/thautwarm'

bugs.python.org fields:

activity = <Date 2020-03-04.18:25:34.149>
actor = 'BTaskaya'
assignee = 'none'
closed = True
closed_date = <Date 2020-03-04.18:25:34.150>
closer = 'BTaskaya'
components = ['Library (Lib)']
creation = <Date 2019-01-01.18:02:50.361>
creator = 'thautwarm'
dependencies = []
files = []
hgrepos = []
issue_num = 35632
keywords = []
message_count = 3.0
messages = ['332845', '357684', '363372']
nosy_count = 3.0
nosy_names = ['pablogsal', 'thautwarm', 'BTaskaya']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue35632'
versions = ['Python 3.9']

[thautwarm]

Although Suite is not an actual AST used in CPython, it's quite useful when performing some code analysis.

Suite is a sequence of statements which could be used to represent a block whose context inherits from outside block's.

Also, the document said it's useful in Jython.

I wonder if we could support unparse for Suite through making a tiny modification to

https://github.com/python/cpython/blob/master/Tools/parser/unparse.py

def _Suite(self, tree):
      for stmt in tree.body:
         self.dispatch(stmt)

[isidentical]

Tools/parser/unparse.py has been moved under ast module and exposed via ast.unparse() interface. If you want to support custom AST statements, the current version is incapable of doing such changes because of the real unparser class is private. As a workaround you can import it and subclass it /assign a method and then use ast.unparse() but that is a hacky way and there is no one who can guarantee if that unparser class will change its API or not. Currently it uses NodeVisitor API. Also you can use Berker's astor project to do this job, which gives you ability of changing source generator class.

[isidentical]

I just removed Suite node in #62713, so I guess this can be closed.