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Go-style built-ins (retired)

Early G# 0.4 packages shipped the Go-style built-in functions len, cap, append, and delete behind a per-file import Gsharp.Extensions.Go. Later releases retired them, together with the import gate and the Gsharp.Extensions.Go namespace itself: every receiver already carries the member, so a free function that adds no syntax of its own only competed with it. A call to a retired name reports GS0566, whose message names the replacement for that exact site (xs.Length, m.Count, m.Remove(k), …). The names are free for your own functions: a user-defined func len(...) is an ordinary call.

Replacements​

Retired Receiver Write instead 
len(xs) array [N]T, slice []T, string, rectangular array xs.Length (rectangular arrays also have .Rank and .GetLength(d)) 
len(m) map[K, V] m.Count 
len(ch) a channel you constructed (Chan[T]) ch.Length() 
cap(xs) slice removed — a slice is a fixed CLR array whose capacity is its length, xs.Length 
cap(ch) a channel you constructed ch.Capacity 
append(xs, v) slice keep a growable List[T] and call .Add(v); a slice is a fixed CLR array 
delete(m, k) map[K, V] m.Remove(k) 
close(ch) channel ch.Close() 
make(chan T[, n]) — chan[T]() (rendezvous), chan[T](n), Chan.Unbounded[T]() 
import System
import System.Collections.Generic

var nums = []int32{10, 20, 30}
Console.WriteLine(nums.Length)        // 3

var grown = List[int32]()
grown.Add(40)
Console.WriteLine(grown.Count)        // 1

var counts = map[string,int32]{"a": 1, "b": 2}
counts.Remove("a")
Console.WriteLine(counts.Count)       // 1

Console.WriteLine("hello".Length)     // 5

Because []T is T[] and map[K, V] is Dictionary[K, V] (the same type), no new API ships with this change; the members were always there.

See also​