15 May
2008
15 May
'08
1:52 p.m.
2008/5/15 Yitzchak Gale
So I think the best and simplest idea is to make the letter lambda a keyword. True, you need a space after it then. You already need spaces between the variables after the lambda, so anyway you might say that would be more consistent.
You could use a zero width space (U+200B) to preserve the appearance of mathematical notation. I don't know if this is already treated as whitespace but it probably should be. There are also several thin space characters (U+2008 punctuation space, U+2009 thin space, U+200A hair space) that might be better, particularly between variables in a multi-parameter lambda. Andy