spacing before list continuations

[Jacob Rus]

John MacFarlane wrote:

> Is this a bug, or should the documentated syntax be revised?  This more

> relaxed behavior is nice in some cases, but it seems to cause problems

> in others.  For example, this ought to be a nested list followed by a

> horizontal rule:


I say it's a bug, because it leads to problems like the weird lists when 
you do:

   1. blah
   9. blah blah
  10. blah blah blah

This stuff should be consistent, and any paragraph with <4 spaces of 
indentation should be considered to exit any block elements, while any 
between 4 and 7 spaces should be considered to continue the block.  When 
it comes to numbered/unnumbered lists, any number from 1-3 spaces should 
be ignored, whereas 4-7 spaces should indicate one nested level, etc. etc.

These should be consistent between block quotes, numbered and unnumbered 
lists, and any other present or future block elements.

And this stuff should be much more clearly explained in the syntax 
definition on daringfireball.net, along with how implementations should 
work on the edge cases.

Things like this are where having a true grammar really shows its 
benefits, as the grammar clarifies both for humans and computers exactly 
how the parsing should proceed.  As is, it's hard to tell without 
actually running some text through markdown.pl what is going to happen 
with edge cases.

-Jacob