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--- TODO
+++ TODO
+ - fix the object stream parser to split input at logical boundaries, as
+ provided by the object index ("N pairs of integers") at the beginning of the
+ stream data.
+
+ this follows discussion with peter wyatt where he initially said that the
+ objects should be delimited by normal PDF token rules, but PDFA then came
+ to the conclusion that, in fact, this was a mistake and the logical
+ begin/end info should delimit things. i.e. if your index says that an object
+ begins at offset 0 and ends at offset 3, followed by one that ends at 6, and
+ the input is "123456", this parses as two numbers, 123 and 456.
+
+ currently the code follows the incorrect former approach, (re-) using the
+ "elemr" parser that is otherwise used with arrays. the above example would
+ parse as one element, the number 123456, in contradiction to the index
+ (which we parse but ignore).
+
+ we have to explicitly walk the index, run our "obj" parser on each
+ respective snippet of input, and wrap the results up in a parse result. we
+ should also validate conditions on the index beforehand. these are
+ thankfully sane (monotonic offsets etc.) and mentioned in the spec.
+
- move main routine(s) and filter implementation(s) into separate source
files. e.g.:
- main.c: main function and helpers; starting from its include block
a validation (h_attr_bool) should let the parse fail if applicable (severity
vs. strictness). non-fatal violations should be extracted and printed to
stderr after the parse.
+ - somehow rid VIOL() of the internal parser for getting at the severity
+ parameter. this is, i guess, an artefact of h_action() taking a single void
+ pointer of context, so it was not trivial to pass two arguments (message and
+ severity) to the action.
- (maybe?) change stream parsing to just stop at "endstream endobj" when
/Length is indirect and the filter or postordinate parser doesn't delimit
one pure island.
- parse and print content streams.
+ - parse/validate additional stream types/filters (images...).
+ - consider reviving the effort to get "obj" to parse with LALR. the messy
+ grammar for arrays with "elemd", "elemr", etc. still stems from project, as
+ does the explicit handling of whitespace -- note that TOK() is only used in
+ KW() and that no instances of KW() remain under "obj".
+
+ alternatively, consider fully reverting the grammar to its clearer PEG form.
+ i would probably keep the explicit whitespace, though.
+
+ what stopped me before was the difficulty to resolve some things without
+ precedence rules; specifically line endings in string literals.
+ is <CR><LF> a "crlf" or a "cr" followed by an "lf"? LALR cannot decide
+ unless you encode that anything following a "cr" doesn't start with <LF>.
+ string literals are currently defined differently. the best way to do it,
+ AFAICS, would be to match (in string literals) all subsequent line endings
+ in one nonterminal and to encode there that a plain "cr" is never followed
+ by "lf".
+
+ FWIW, the motivation for LALR parsing of "obj" was the prospect of parsing
+ an object stream incrementally, as chunks come in from the decompressor
+ (or an arbitrary filter chain).
+
+ NB: the reason why we must distinguish "crlf" from "cr" "lf" at all is of
+ course that in a string literal, the former means "\n" and the latter means
+ "\n\n".
+
- implement random-access ("island") parser (walking objects from /Root).
i'm not sure how much we need to know about the "DOM" for this. maybe
nothing? since everything is built out of basic objects and we can just
