Chris Pearce, that is correct. They acknowledge that the parser section is useful but not required.
Kyle Barnhart On 2013-02-04 8:04 PM, "Chris Pearce" <[email protected]> wrote: > It's not clear to me what the issue is. > > Are you saying: > > 1. The WebVTT spec specifies the parser algorithm, and > 2. the WebVTT spec specifies a grammar for valid WebVTT cues/files, and > 3. some people don't want to implement the specified parser algorithm? > > Is that the correct? If not can you summarise succinctly what the issue is > please? > > > Chris Pearce. > > > > On 5/02/2013 12:38 p.m., Kyle Barnhart wrote: > >> This post stems from a discussion on the Seneca IRC channel and then on >> the >> webvtt-dev mailing list. David Humphrey has asked for us to move the >> technical discussion to be this mailing list. >> >> The issue concerns which sections of the WebVTT specification our parser >> library must be compliant with. Everyone agrees we want to make a WebVTT >> implementation that conforms to the specification, so I will only copy a >> few quotes on the subject at the root our disagreement. >> >> This issue is very important because solving is soon will make it clear >> how >> the work needs to be done, thus reducing work to change it later (if >> required) or the effort involved in perusing two lines of work. Second, it >> determines the behavior of WebVTT when it is implemented. >> >> ------------------ >> >> Kyle Barnhart: >> "These [parser rules] are the only rules a parser/interpreter needs to >> comply with, this was the deliberate intention of having a parser section. >> It is important to note that the interpreter can be written in away way so >> long as it arrives to the same results as in the parsing specifications. >> There should be test to ensure compliance." >> >> Caitlin Potter: >> "... the parser is modeled after the syntax, because the parser's job is >> to >> process input according to that syntax or grammar." >> >> Kyle Barnhart: [By validator I mean it only ensures compliance with the >> syntax rules] >> "If the parser is actually only a validator, when are we writing an >> interpreter? We cannot send anything to a browser to process without one." >> >> Caitlin Potter: >> "The rules of a parser come from the syntax or grammar. The parser spec >> isn't actually required for interpreting data in the files, because that >> all comes from the grammar, and additional information about the markup >> elements." >> >> ----------------- >> >> To summarize, some maintain that our parser library needs to be compliant >> with the sytnax rules of the specification and so the parser library tests >> should ensure that. The parser section is not required but useful. I >> maintain that the parser library must conform the parser rules in the >> specification, and that checking syntax rules is not required but useful. >> We both maintain that the test for the parser library should reflect the >> part of the specification that is required. >> >> I have the following quotes from people I have talked with and research >> into the issue I have done. >> >> "When writing something that reads WebVTT files, be very sure to parse it >> as specified by the parser--*not* by reading the syntax and coming up with >> your own parsing algorithm." >> - Glenn Maynard >> >> "[Syntax rules] are requirements for writing, not for parsing. >> Requirements >> in that section don't apply to you." >> - Simon Pieters >> >> "'It's a bit unusual for a standard to specify the parsing algorithm, but >> I >> can understand why.' >> It's not unusual for modern specs. It's a much more dependable way of >> getting to consistent behavior than only specifying a format." >> - Glenn Maynard >> >> Also... >> >> "It should follow what implementations do as well. So if there's something >> strange there it might be a bug in the spec." >> - Velmont >> >> "yeah, what Velmont said. If there's a reason to implement something other >> than the spec, we should change the spec." >> - Ian Hickson >> >> "If the code is to end up in Gecko, it had better follow the specification >> to the letter" >> - Ms2ger >> >> Please help us to determine which is the correct approach. >> >> Thank You, >> >> Kyle Barnhart >> > > _______________________________________________ dev-media mailing list [email protected] https://lists.mozilla.org/listinfo/dev-media
