Account Options

  1. Sign in
The old Google Groups will be going away soon, but your browser is incompatible with the new version.
Google Groups Home
« Groups Home
golang-nuts
Home
+ new post
About this group
Join this group
Message from discussion Function accepting a slice of interface types.
The group you are posting to is a Usenet group. Messages posted to this group will make your email address visible to anyone on the Internet.
Your reply message has not been sent.
Your post was successful
 
From:
To:
Cc:
Followup To:
Add Cc | Add Followup-to | Edit Subject
Subject:
Validation:
For verification purposes please type the characters you see in the picture below or the numbers you hear by clicking the accessibility icon. Listen and type the numbers you hear
 
Scott Pakin  
View profile  
 More options Nov 9 2010, 8:33 pm
From: Scott Pakin <scott+...@pakin.org>
Date: Tue, 9 Nov 2010 17:33:12 -0800 (PST)
Local: Tues, Nov 9 2010 8:33 pm
Subject: Re: Function accepting a slice of interface types.
Print | View thread | Show original | Report this message | Find messages by this author
On Nov 9, 4:13 pm, SnakE <snake.sc...@gmail.com> wrote:

> When you pass a string to a function expecting `interface{}` the runtime
> constructs that two-field structure and passes it instead.  Asymptotic cost
> of this operation is amortized O(1).

> An array of strings is internally a C array of pointers.  An array of
> `interface{}` internally is a C array of structs of two pointers each.  To
> convert `[]string` into `[]interface{}` the compiler would have to allocate
> another array, then convert each string individually.  The cost is suddenly
> O(n) + cost of an allocation which can be major in many different ways.

But why can't Go simply box the entire array as a whole (at a cost of
O(1))?  Per-access costs would be comparable to those incurred by
accessing a string passed to a function expecting an interface{}.
right?

I like the idea of being able to pass a []string (or whatever) to an
[]interface{} and don't see why this feature is inherently costly.


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Create a group - Google Groups - Google Home - Terms of Service - Privacy Policy
©2013 Google