Support multi-statement prompts in PDB REPL #159887

Feature or enhancement

Current vs expected:

 (Pdb) class A:
 ...       pass
 ...
 ...   class B(A):
 ...       pass
 ...
 ...   B()
 ...
-*** SyntaxError: invalid syntax
+<__main__.B object at 0x107affce0>

(Whereas the main interactive REPL supports multi-class one-turn prompts from the user).

Found during stress-testing #157612 and discussed with @gaogaotiantian.

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-159887: Support multiple statements in pdb prompts #160039