Peter Norvig wrote
That may be a good analogy, and as I said, I'm willing to try. But I still think one character is easier to ignore than four, and that there is no compelling argument for 'self' over '_', while there is a positive reason for parens (ease of automated parsing tools).
The primary arguments against '_' are that it already has meaning. I can think of three, off the top of my head. Interactive mode uses this as "result of last expression". The i18n code uses it as a function _('translate me'). Zope uses it in DTML (python) expressions as the default namespace.
I'd also add the subjective argument that it's ugly, and looks far too magical and perl-like. I don't _want_ it to disappear into the background, as it's going to cause me pain if I miss it.