book: Change 'unified function call syntax' to 'associated item loookup syntax'

[nham]

see rust-lang/rfcs#1140

One issue is that this still doesn't have any examples of lookup of items that aren't associated with traits.

[rust-highfive]

r? @alexcrichton

(rust_highfive has picked a reviewer for you, use r? to override)

[nham]

r? @steveklabnik

[steveklabnik]

UFCS, while not a perfect name, is generally the name for this kind of thing. Creating a brand new term with an awkward name is 👎, as far as I'm concerned.

That doesn't mean that I'm totally opposed, but I think that we need a good reason to deviate here.

[nham]

I'm not completely sold on "Associated Item Lookup Syntax", but the name is not really the major point here. The main thing I'm interested in pointing out in the docs is that "UFCS" syntax is not limited to function calls, but also works for associated types and constants. However, adding such a note to the UFCS chapter without changing the name seems to not work: if it's not limited to function calls, why introduce the 'UFCS' terminology?

Could the chapter title be "Lookup Disambiguation Syntax" instead? Perhaps the chapter could still mention that in the case of function calls, the syntax is sometimes called UFCS.

[bluss]

Core team discussed naming things: (notes)

[steveklabnik]

Yes, I think that we are not going to be pursuing this particular approach forward, though I do think that it should be changed. I would prefer to see the UFCS chapter just disappear, and have this syntax be explained along with other function stuff, as the last part of that note mentions.