satyr/coco — pull request #182 by qqueue (2012-10-18 00:50:11+00:00)
Title: Pipe no longer clobbers `_`, fixes #181

...Is the end goal here, but I have questions on the approach, if you're willing to help.

The relevant code appears to be:

grammar.co:
```coco
o 'Expression |> Expression' -> Block $1 .pipe $3
```

ast.co:
```coco
pipe: -> @lines.push Assign(Var \_; @lines.pop!), it; this
```

I also found `scope#temporary` for getting a new name, but I'm unsure how to change the `_` variable within the right-hand side of the pipe to the temporary binding. Is the implementation of pipe as just the `Node#pipe` method sufficient to do this, or would it be better to make `Pipe extends Node` to hold the logic for this?