do node consistency

[krux02]

do nodes are now consistently lambda expressions no matter if they have arguments or not. stmtLists are no longer lifted implicitly to lambda expressions

Summary

• do nodes without arguments are not implicitly converted to bare stmtList anymore.
• bare stmtList is not lifted to a lambda expression anymore.
• The behavior that got removed was a hack that cause more problems than it solved.

Details

It caused problems in my macro library, especially the implicit lifting of stmtList to a λ expression is a liability that is really hard to work around. It is not a feature to be proud upon. It is a breaking change, especially cases when do blocks need to be treated as bare stmtList and not λ expressions.

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This is a change I've made a long time ago on my own fork of Nim.

[krux02]

@haxscramper the code I broke is mostly code you wrote, so I would really like to hear your opinion about it.

[alaviss]

Can you provide an example for the behavior change?

[saem]

This video from racket conf offers a better solution for alternatives and handling multiple groups to be associated with a previous line: https://youtu.be/UUWYTW3Xck8

Preview:

foo(stuff):
  | One statement
    Still part of one statement
  | Second statement, both one and two are arguments to foo

Without something as the above we can't move forward with this do change.

[saem]

This has gone stale and the multiple statements via pipes is required first. It can be resurrected if and when needed.