Bug in tuple and list unpacking

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#784 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
38/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
javascript, python
Domain
compilers

Research direction

Start by reproducing the issue with the main.py examples and the reported Transcrypt command. Compare the generated JavaScript for tuple/list unpacking with the expected (3, 7) result, then trace the relevant compiler handling and add coverage showing that the unpacked list is expanded rather than retained as a nested value.

Written by the indexing model from the issue text.

Description

IS: bug? 
# main.py
a = [3]
print((*a, 7))

transcrypt -m main.py

//  [...]
export var a=[3];
print(tuple([a, 7]))

which thus produces ([3], 7) and not (3, 7)!

On the other hand

# main.py
a = [3]
print(tuple(*a, 7))

produces the correct transcryption print(tuple(...a, 7)).

Transcrypt version: 3.9.0

Dominant language
Python
Stars
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Forks
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No merged PRs in 30d

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  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.

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