Your quoting of the ANSI standard, plus the defacto historical 
background of every dialect for #respondsTo:, is what has swayed me that 
what my understanding of the responsibility of #respondsTo: is, and what 
the *actual* responsibility is, are two different things.

Learn something every day.

Nevin


Richard A. O'Keefe wrote:

<...snip...>

>Well, *this* is what *I* call unfortunate.
>It's the implementation of #resondsTo: in GNU Smalltalk.
>
>respondsTo: aSymbol
>    "Returns true if the receiver understands the given selector"
>    ^self class canUnderstand: aSymbol
>
>You'll notice that it's the same *implementation* as the traditional
>one, but the comment now describes what you seem to say is the actual
>responsibility.  The two disagree.  Someone wanting to know whether
>they can use #respondsTo: will stop reading here, having been assured
>that yes, they can.  But they can't.  To find out that they can't,
>they'd have to go on and read #canUnderstand:.
>
>What *is* "the actual responsibility of the method"?
>The only reasonably authoritative source available to me is the
>ANSI Smalltalk standard.
>
>    5.3.1.15
>	A message to perform a selector, <code>selector</code>',
>        for a given receiver will result in a "message not understood"
>        condition if and only if the value of
>	    <code>receiver respondsTo: selector</code>
>        is <i>false</i>.
>
>    5.3.1.19 Message: respondsTo: selector
>	Definition: <Object>
>	    Return <i>true</i> if the receiver has a method in its
>	    behavior that has the message selector <code>selector</code>
>	    Otherwise return <i>false</i>.
>
>That is, according to the ANSI Smalltalk standard,
>"the actual responsibility of the method" is EXACTLY WHAT THE COMMENT
>IN SQUEAK SAYS IT IS.
>
>  
>
<...snip...>