Often when people want to type some pinyin, they put tone marks as numbers:
ni3 chi1le ma?
But it's much easier to read with tone marks as accents:
wǒ chīguòle
I wrote a pinyin formatter (available at shinyandnew.ca) which allows for easy formatting of pinyin based on numeric tone entry (type v for ü). Maybe this, or something like it, could be integrated here?