On 05/29/13 09:51, Larry Evans wrote:
On 05/29/13 07:59, salvatore dario minonne wrote:
ATLR is LL as well More specifically, ANTLR is LL(k) for some k>0:
http://en.wikipedia.org/wiki/LL_parser
Spirit is a PEG:
http://www.boost.org/doc/libs/1_43_0/libs/spirit/doc/html/spirit/abstracts/p...
Both PEG and LL)k) are recursive descent; however, LL(k) means the parser can lookahead K tokens to decide which alternative to parse. I think spirit's expect operator means it can lookahead 1 token. Also, spirit will try alternatives in order until it finds a match; The parsing_expression_grammar.html contain a link to:
http://pdos.csail.mit.edu/~baford/packrat/popl04/ which contains a link to a .pdf and ps.gz file. My Adobe reader could not read the.pdf file; however, my gv could read the unzipped ps.gz file, whose page 1 supported the description given above for how spirit handles the alternative operator, '|', which, on page 1 of the ps file is called the "prioritized choice operator, '/'". [snip] HTH. -Larry