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[Bug 20505] New: merge getInput, getOutput -> getPort() or getPortById()

From: <bugzilla@jessica.w3.org>
Date: Mon, 24 Dec 2012 08:15:56 +0000
To: public-audio@w3.org
Message-ID: <bug-20505-5429@http.www.w3.org/Bugs/Public/>

            Bug ID: 20505
           Summary: merge getInput, getOutput -> getPort() or
    Classification: Unclassified
           Product: AudioWG
           Version: unspecified
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: MIDI API
          Assignee: dave.null@w3.org
          Reporter: w3c@marcosc.com
        QA Contact: public-audio@w3.org

The methods getInput() and getOutput() effectively do the same thing (evident
also by the amount of duplicate text in the spec); as such, they should be
merged. Furthermore, it's not clear (in the spec) as why there are 3 different
ways to get a MIDIPort. I would like to suggest that these two methods be
merged into a single method and the way to be one way to get a MIDIPort: by its
ID… hence getPort(id) or getPortById(id);


1. getInput/Output(MIDIPort)… doesn't make much sense, as why is a developer
requesting a MIDIPort with a MIDIPort they already have? I'm sure there is
something I'm missing here.

2. getInput/Output(short): first, short here doesn't make much sense, given
that a WebIDL short is defined as:
"The short type is a signed integer type that has values in the range [−32768,
32767]". So requesting negative indexes don't make any sense here. In addition,
this is basically the same as doing:

var port = midiAccess.getInputs()[x];

Additionally, the ordering of the ports may or may not be consistent after each
session, so saying getInput(number) is inherently unreliable. Also, it's kinda
unhelpful is you want to, for instance, get the last available port. This is
because midiAccess has no length property. The only way to get the length is to
first call getInputs(), and get the length from there… but then you already
have the list of inputs, in so you don't then need to call getInput( number ),
because it's already the same as inputs[number].

3. getInput/Output( id ): this is probably the only one that makes sense. It's
a cheap way of checking if a previously used exists:

var favInstrument = midiAccess.getInput(localStorage.fav)
if(favInstrument){ … }
Also, if target is is not found, just return null. Please don't throw an
exception. Throwing exceptions should be done in "exceptional" circumstances,
not on simple lookups.

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Received on Monday, 24 December 2012 08:15:57 UTC

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