On Oct 2, 2007, at 9:52 , Alex Queiroz wrote:
(parseDottedList ls) <|> (parseProperList ls)
I've factored out the common left sub-expression in
parseLeftList. The problem is that "..." is a valid identifier so when
inside the left of the list the parser sees a single dot, it tries to
match it with "...", which fails. Can anybody give advice on how to
rewrite these list parsing functions?
try (parseDottedList ls) <|> parseProperList ls
Overuse of try is a bad idea because it's slow, but sometimes it's
the only way to go; it insures backtracking in cases like this.
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED]
system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon university KF8NH
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