gno.land/r/moul/x/daily/multisetdemo/v0⧉

1// Package multisetdemo is a small gnoweb demo of the bag / frequency counter2// provided by the [p/moul/x/daily/multiset](/p/moul/x/daily/multiset/v0)3// library: word frequencies, ranking, and multiset algebra.4//5// It contains no counting logic of its own. Stateless, so Render is6// deterministic — which is precisely what the library is for.7package multisetdemo89import (10	"strconv"11	"strings"1213	"gno.land/p/moul/x/daily/multiset/v0"14)1516const sample = "the quick brown fox jumps over the lazy dog the fox barks and the dog barks"1718// Render renders the demo for gnoweb.19func Render(path string) string {20	var b strings.Builder21	b.WriteString("# Multiset\n\n")22	b.WriteString("A bag that counts duplicates, demoing the ")23	b.WriteString("[`p/moul/x/daily/multiset`](/p/moul/x/daily/multiset/v0) library.\n\n")2425	m := multiset.FromSlice(strings.Split(sample, " "))2627	b.WriteString("## Word frequencies\n\n")28	b.WriteString("> " + sample + "\n\n")29	b.WriteString("`" + strconv.Itoa(m.Total()) + "` words, `")30	b.WriteString(strconv.Itoa(m.Distinct()) + "` distinct.\n\n")3132	b.WriteString("## `MostCommon(5)`\n\n")33	b.WriteString("| rank | word | count |\n|---|---|---|\n")34	for i, e := range m.MostCommon(5) {35		b.WriteString("| " + strconv.Itoa(i+1) + " | `" + e.Elem + "` | " +36			strconv.Itoa(e.Count) + " |\n")37	}38	b.WriteString("\nNote the ties. `barks`, `dog` and `fox` all occur twice and are ")39	b.WriteString("ranked **alphabetically** — the order is count descending, then ")40	b.WriteString("element ascending. That second key is not decoration: without it the ")41	b.WriteString("ranking would fall back on map iteration order, which gno leaves ")42	b.WriteString("unspecified, and two nodes could render different tables.\n\n")4344	b.WriteString("## Algebra\n\n")45	a := multiset.FromSlice([]string{"x", "x", "x", "y"})46	c := multiset.FromSlice([]string{"x", "x", "z"})47	b.WriteString("With `A = {x:3, y:1}` and `B = {x:2, z:1}`:\n\n")48	b.WriteString("| op | meaning | result |\n|---|---|---|\n")49	b.WriteString("| `Union` | max of each count | " + brief(a.Union(c)) + " |\n")50	b.WriteString("| `Intersect` | min, common only | " + brief(a.Intersect(c)) + " |\n")51	b.WriteString("| `Sum` | counts added | " + brief(a.Sum(c)) + " |\n")5253	b.WriteString("\n## Removal\n\n")54	d := multiset.FromSlice([]string{"a", "a", "a"})55	b.WriteString("Starting from " + brief(d) + ":\n\n")56	d.Remove("a")57	b.WriteString("- after `Remove(\"a\")` → " + brief(d) + "\n")58	d.RemoveN("a", 100)59	b.WriteString("- after `RemoveN(\"a\", 100)` → " + brief(d) +60		" — over-removing clears the element instead of going negative\n")61	return b.String()62}6364func brief(m *multiset.MultiSet) string {65	if m.IsEmpty() {66		return "`{}`"67	}68	parts := []string{}69	for _, e := range m.Elements() {70		parts = append(parts, e+":"+strconv.Itoa(m.Count(e)))71	}72	return "`{" + strings.Join(parts, ", ") + "}`"73}74