[Swift-devel] Join function?

[Michael Wilde]

for an array created like this:

string a[] = ["a","b","c"];

@length(a) returned 3 when called from open code, but when applied to the argument s[] inside a function, to which a was passed, returned 0 inside that function.

In trying to replicate this without divulging the source code to recursive strjoin() ;) which I was leaving as an exercise to the (email) reader, I see that there is further weirdness, likely due to confusion/race between @length() and array closing semantics.

For example:

com$ cat length.swift
string a[] = ["a","b","c"];

string b[];
b[0] = "a";
b[1] = "b";
b[2] = "c";

(string o) strjoin(string s[], string sep)
{
 #  o = strjoinf(s, sep, @length(s));  # length returns 0 here!
 trace("len inside", at length(s));

}

trace("len a outside", @length(a));
trace("len b outside", @length(b));

string js = strjoin(a,"---");

####

Gives this non-determinsitic output:

com$ swift length.swift

no sites file specified, setting to default: /home/wilde/swift/rev/trunk/etc/sites.xml
Swift trunk swift-r5739 cog-r3368 (cog modified locally)

RunID: 20120403-1559-ulurhdrf
Progress:  time: Tue, 03 Apr 2012 15:59:31 -0500
SwiftScript trace: len b outside, 2
SwiftScript trace: len inside, 3
SwiftScript trace: len a outside, 3
Final status: Tue, 03 Apr 2012 15:59:31 -0500

com$ swift length.swift

no sites file specified, setting to default: /home/wilde/swift/rev/trunk/etc/sites.xml
Swift trunk swift-r5739 cog-r3368 (cog modified locally)

RunID: 20120403-1559-x3ovo0i6
Progress:  time: Tue, 03 Apr 2012 15:59:39 -0500
SwiftScript trace: len b outside, 2
SwiftScript trace: len a outside, 0
SwiftScript trace: len inside, 0
Final status: Tue, 03 Apr 2012 15:59:39 -0500

com$ swift length.swift

no sites file specified, setting to default: /home/wilde/swift/rev/trunk/etc/sites.xml
Swift trunk swift-r5739 cog-r3368 (cog modified locally)

RunID: 20120403-1559-zkglev13
Progress:  time: Tue, 03 Apr 2012 15:59:42 -0500
SwiftScript trace: len b outside, 3
SwiftScript trace: len a outside, 0
SwiftScript trace: len inside, 0
Final status: Tue, 03 Apr 2012 15:59:42 -0500

com$ swift length.swift

no sites file specified, setting to default: /home/wilde/swift/rev/trunk/etc/sites.xml
Swift trunk swift-r5739 cog-r3368 (cog modified locally)

RunID: 20120403-1559-5ttgglqc
Progress:  time: Tue, 03 Apr 2012 15:59:48 -0500
SwiftScript trace: len a outside, 0
SwiftScript trace: len b outside, 3
SwiftScript trace: len inside, 3
Final status: Tue, 03 Apr 2012 15:59:48 -0500
com$ 


----- Original Message -----
> From: "Jonathan Monette" <jonmon at mcs.anl.gov>
> To: "Mihael Hategan" <hategan at mcs.anl.gov>
> Cc: "Glen Hocky" <glen842 at uchicago.edu>, "swift-devel at ci.uchicago.edu Devel" <swift-devel at ci.uchicago.edu>
> Sent: Tuesday, April 3, 2012 3:47:18 PM
> Subject: Re: [Swift-devel] Join function?
> I do not know what Mike was experiencing. I was going to investigate
> myself and ask what his example was. Perhaps he can elaborate more on
> what he was witnessing.
> 
> On Apr 3, 2012, at 3:46 PM, Mihael Hategan wrote:
> 
> > On Tue, 2012-04-03 at 15:43 -0500, Jonathan Monette wrote:
> >> So Swift does have an @length built-in function that returns the
> >> length of an array. Mike said he also tried coming up with a Swift
> >> function to this same think and said that @length does not always
> >> behave as he thought it should. I am going to look into fixing
> >> @length so we do have a way finding the length of an array.
> >
> > Can you be more specific as to what's wrong with @length?
> >
> 
> _______________________________________________
> Swift-devel mailing list
> Swift-devel at ci.uchicago.edu
> https://lists.ci.uchicago.edu/cgi-bin/mailman/listinfo/swift-devel

-- 
Michael Wilde
Computation Institute, University of Chicago
Mathematics and Computer Science Division
Argonne National Laboratory