Re: Expanding slices as arguments

[Aiden]

Found https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/d_jPf74RMCo, is using reflection still the
recommended approach?

On Tuesday, 18 December 2012 14:23:38 UTC, Aiden wrote:

Hi all,

Tried Googling, but can't find much ...

With

func Command(name string, arg ...string) *Cmd

Is there a way to pass a slice as the second parameter? I have an set of arguments for a command.

Cheers!

[Peter]

http://golang.org/ref/spec#Passing_arguments_to_..._parameters

[Igor Cananea]

This works: http://play.golang.org/p/zWODNmZjvH

    Igor Chaves Cananéa

"Designing grand concepts is fun; finding nitty little bugs is work." (Frederick P. Brooks Jr - The Mythical Man-Month)
Visitem meus blogs! http://igorbh.blogspot.com e http://nerdpensando.blogspot.com/

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[Aiden]

Thanks Peter, looks like what im after :D

[Aiden]

Nice example, Thanks :)
Didn't think I came across this reading effective ... might be worth popping in there?

[minux]

On Tue, Dec 18, 2012 at 10:41 PM, Aiden <aide...@gmail.com> wrote:

Nice example, Thanks :)
Didn't think I came across this reading effective ... might be worth popping in there?

the introduction section of effective Go says:

http://golang.org/doc/effective_go.html#introduction

> This document gives tips for writing clear, idiomatic Go code. It augments the language specification, 

> the Tour of Go, and How to Write Go Code, all of which you should read first.

which means that, you really should read the language specification before effective Go.

[Peter]

Well perhaps that needs looking at. Go's spec, whilst far simpler than many other languages', is still quite a long document. Effective Go is certainly not a subset, but it does cover much of the same material - someone who has read the spec does not need to be told "The control structures of Go are related to those of C but differ in important ways".

It's great that the definitive spec is so accessible, but I don't see that it should be read before "Effective Go".

[Patrick Mylund Nielsen]

Agreed. Effective is read after the introduction, whether or not it was supposed to be.

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[minux]

On Tue, Dec 18, 2012 at 10:54 PM, Peter <peter.a...@gmail.com> wrote:

Well perhaps that needs looking at. Go's spec, whilst far simpler than many other languages', is still quite a long document. Effective Go is certainly not a subset, but it does cover much of the same material - someone who has read the spec does not need to be told "The control structures of Go are related to those of C but differ in important ways".

It's great that the definitive spec is so accessible, but I don't see that it should be read before "Effective Go".

I just skimmed through effective Go document, and i think using ... to pass a slice to

...interface{} parameter is documented and explained.

Within the function Printf, v acts like a variable of type []interface{} but if it is passed to another variadic function, it acts like a regular list of arguments. Here is the implementation of the function log.Println we used above. It passes its arguments directly to fmt.Sprintln for the actual formatting.

// Println prints to the standard logger in the manner of fmt.Println.
func Println(v ...interface{}) {
    std.Output(2, fmt.Sprintln(v...))  // Output takes parameters (int, string)
}

We write ... after v in the nested call to Sprintln to tell the compiler to treat v as a list of arguments; otherwise it would just pass v as a single slice argument.