ringbufferdemo.gno

 1// Package ringbufferdemo is a small gnoweb demo of the fixed-capacity FIFO
 2// provided by the [p/moul/x/daily/ringbuffer](/p/moul/x/daily/ringbuffer/v0)
 3// library: it pushes more entries than the buffer can hold and shows what
 4// survives, plus what each overflowing push evicted.
 5//
 6// It contains no buffer logic of its own. Stateless, so Render is deterministic.
 7package ringbufferdemo
 8
 9import (
10	"strconv"
11	"strings"
12
13	"gno.land/p/moul/x/daily/ringbuffer/v0"
14)
15
16const capacity = 4
17
18var feed = []string{"alpha", "bravo", "charlie", "delta", "echo", "foxtrot"}
19
20// Render renders the demo for gnoweb.
21func Render(path string) string {
22	var b strings.Builder
23	b.WriteString("# Ring Buffer\n\n")
24	b.WriteString("A fixed-capacity FIFO that overwrites its oldest entry, demoing the ")
25	b.WriteString("[`p/moul/x/daily/ringbuffer`](/p/moul/x/daily/ringbuffer/v0) library.\n\n")
26	b.WriteString("Capacity **")
27	b.WriteString(strconv.Itoa(capacity))
28	b.WriteString("**, pushing ")
29	b.WriteString(strconv.Itoa(len(feed)))
30	b.WriteString(" entries:\n\n")
31	b.WriteString("| push | evicted | contents (oldest → newest) |\n|---|---|---|\n")
32
33	r := ringbuffer.New(capacity)
34	for _, v := range feed {
35		ev, dropped := r.Push(v)
36		b.WriteString("| `")
37		b.WriteString(v)
38		b.WriteString("` | ")
39		if dropped {
40			b.WriteString("`" + ev + "`")
41		} else {
42			b.WriteString("—")
43		}
44		b.WriteString(" | `")
45		b.WriteString(strings.Join(r.Slice(), " "))
46		b.WriteString("` |\n")
47	}
48
49	b.WriteString("\n> The buffer never grows: once full, each push costs the oldest entry. ")
50	b.WriteString("On chain that bound is the point — an unbounded queue is an unbounded storage bill.\n")
51	return b.String()
52}