instaparse 2016-07-07

@seylerius not sure what exactly you're confused about, but here are some examples: imagine you're parsing the following input:

aaaa
bbb
cccccc
the grammar could look like
S = A '\n' B '\n' C
A = 'a'+
B = 'b'+
C = 'c'+

or

S = #'a+\n' #'b+\n' #'c+'

either \n or \\n would work if you are inside a Clojure string.

S = A ows B ows C
A = 'a'+
B = 'b'+
C = 'c'+
(* optional whitespace *)
<ows> = <#'\s*'>

For that example, inside a Clojure string you would need to change \s to \\s.

@aengelberg: Also, how would you modify what would normally be a .* to not eat an optional :[a-zA-Z0-9_@]+:([a-zA-Z0-9_@]+:)* that follows it? Or would you just post-process that out after?

so you're trying to parse #"shown-part hidden-part" but only return "shown-part" in the parse result?

you could use the regex lookahead to omit it from the result, but then actually parse it (with instaparse's <> hiding feature) in order to properly advance the parser.

S = #'shown-part(?=hidden-part)' <#'hidden-part'>

or unhide the second #'hidden-part' if you actually do want it in the parse tree, but separate from #'shown-part'.

@aengelberg: More like org-mode headlines allow tags at the end in that style. Not hidden so much as separate.

@aengelberg: Any particular instaparse way to go multi-line, or just specify it in the regexps?