I think you're underselling (1), which provides the compiler with exactly the kind of information it needs to generate extremely efficient code while also providing names.
-- John On Oct 6, 2014, at 8:44 AM, Tamas Papp <[email protected]> wrote: > Hi, > > AFAIK tuples are the recommended way to return multiple values from a > function, but this requires that the programmer remembers the order of > values. I am wondering what the correct idiom is for returning key/value > pairs, similarly to alist/plist in Common Lisp. I have considered the > following alternatives: > > 1. defining a composite type. > > advantages: well-defined constructor and extractor methods. > > disavantages: overkill for most situations, especially if used in 1-2 > places. redefinition cumbersome. > > 2. using hash tables (Dict), especially with their literal [ key1 => > value1 ] syntax. > > advantages: lightweight, can use symbols as keys. well-defined error > when key not found. > > disadvantages: did not benchmark it, but not sure they are > lightweight, for 2-5 values; hash tables usually aren't. > > 3. tuples of tuples. This is apparently what keywords arguments use: > > http://julia.readthedocs.org/en/latest/manual/functions/#keyword-arguments > > "Inside f, args will be a collection of (key,value) tuples, where each > key is a symbol. Such collections can be passed as keyword arguments > using a semicolon in a call, e.g. f(x, z=1; args...). Dictionaries can > be used for this purpose." > > advantages: seems to be the internal mechanism. > > disadvantages: could not (yet) find the julia equivalent of cl:assoc > etc. > > Please advise me, I would like to use the proper style. > > Best, > > Tamas
