Hi Ivo You're more than welcome to contribute to the documentation yourself <https://github.com/JuliaLang/julia/blob/master/CONTRIBUTING.md#improving-documentation> to help clarify anything you found confusing.
Regarding your second point, open() does not return a named type it returns a tuple containing some kind of stream and some kind of process, Pipe is some kind of stream and Process is some kind of process. Hopefully the following code snippet will help clear things up. julia> x = open(`less`) (Pipe(closed, 0 bytes waiting),Process(`less`, ProcessExited(0))) julia> y = typeof(x) (Pipe,Process) julia> typeof(y) (DataType,DataType) help?> issubtype INFO: Loading help data... Base.issubtype(type1, type2) True if and only if all values of "type1" are also of "type2". Can also be written using the "<:" infix operator as "type1 <: type2". julia> issubtype((Base.Pipe, Base.Process), (Base.AsyncStream, Base.Process)) true help?> super Base.super(T::DataType) Return the supertype of DataType T julia> super(Base.Pipe) AsyncStream julia> super(Base.Process) Any So what we can see is that open() does return a (stream, process) tuple but stream should actually be called AsyncStream and process should actually be called Process. Hope this helps Sean On Monday, 5 January 2015 06:59:31 UTC, ivo welch wrote: > > > I am reading again about the type system, esp in > http://julia.readthedocs.org/en/latest/manual/types/ . I am a good > guinea pig for a manual, because I don't know too much. > > a tuple is like function arguments without the functions. so, > > mytuple=(1,"ab",(3,4),"5") > > is a tuple. good. > > what can I do with a typle? the manual tells me right upfront that I can > do a typeof(mytuple) function call to see its types. good. > > alas, then it goes into intricacies of how types "sort-of" inherit. I > need a few more basics first. > > I would suggest adding to the docs right after the typeof function that, > e.g., mytuple[2] shows the contents of the second parameter. the julia cli > prints the contents. the examples would be a little clearer, perhaps, if > one used a nested tuple, like (1,2,("foo",3),"bar"). > > before getting into type relations, I would also add how one creates a > named tuple. since open() does exactly this. well, maybe I am wrong. > the docs say it returns a (stream,process), but typeof( open(`gzcat > d.csv.gz`) tells me I have a (Pipe,Process). > > I know how to extract the n-th component of the open() returned tuple > (with the [] index operator), but I don't know how to get its name. x.Pipe > does not work for open(). > > well, my point is that it would be useful to add a few more examples and > explanations here. > > regards, > > /iaw > >
