feat: refactor govdao structure and examples (gnolang#2379)

- remove `gov/integration/`
- remove `gov/proposals/`
- move the integration test in `gov/dao/*test.gno`
- add `r/sys/validators.Render()`

Signed-off-by: moul <[email protected]>

examples/gno.land/r/gov/dao/prop1_filetest.gno

@@ -0,0 +1,85 @@
+// Please note that this package is intended for demonstration purposes only.
+// You could execute this code (the init part) by running a `maketx run` command
+// or by uploading a similar package to a personal namespace.
+//
+// For the specific case of validators, a `r/gnoland/valopers` will be used to
+// organize the lifecycle of validators (register, etc), and this more complex
+// contract will be responsible to generate proposals.
+package main
+
+import (
+	"std"
+
+	govdao "gno.land/r/gov/dao"
+	"gno.land/r/sys/validators"
+)
+
+func init() {
+	// Create the validators change proposal.
+	changesFn := func() []validators.Change {
+		return []validators.Change{
+			// add a new validator.
+			{Address: std.Address("g12345678"), Power: 1},
+			// remove an existing validator.
+			{Address: std.Address("g000000000"), Power: 0},
+		}
+	}
+
+	// Wraps changesFn to emit a certified event only if executed from a
+	// complete governance proposal process.
+	executor := validators.NewPropExecutor(changesFn)
+
+	// Create a proposal.
+	// XXX: payment
+	comment := "manual valset changes proposal example"
+	govdao.Propose(comment, executor)
+}
+
+func main() {
+	println("--")
+	println(govdao.Render(""))
+	println("--")
+	println(govdao.Render("1"))
+	println("--")
+	govdao.VoteOnProposal(1, "YES")
+	println("--")
+	println(govdao.Render("1"))
+	println("--")
+	println(validators.Render(""))
+	println("--")
+	govdao.ExecuteProposal(1)
+	println("--")
+	println(govdao.Render("1"))
+	println("--")
+	println(validators.Render(""))
+}
+
+// Output:
+// --
+// - [/r/gov/dao:0](0) - manual valset changes proposal example (by g1wymu47drhr0kuq2098m792lytgtj2nyx77yrsm)
+// --
+// # Prop#0
+//
+// manual valset changes proposal example
+// Status: active
+// Author: g1wymu47drhr0kuq2098m792lytgtj2nyx77yrsm
+// --
+// --
+// # Prop#0
+//
+// manual valset changes proposal example
+// Status: accepted
+// Author: g1wymu47drhr0kuq2098m792lytgtj2nyx77yrsm
+// --
+// No valset changes to apply.
+// --
+// --
+// # Prop#0
+//
+// manual valset changes proposal example
+// Status: success
+// Author: g1wymu47drhr0kuq2098m792lytgtj2nyx77yrsm
+// --
+// Valset changes to apply:
+// - g12345678 (1)
+// - g000000000 (0)

examples/gno.land/r/sys/validators/validators.gno

@@ -3,6 +3,7 @@ package validators
 
 import (
 	"std"
+	"strconv"
 
 	"gno.land/p/gov/proposal"
 )
@@ -45,3 +46,15 @@ func getAndResetChanges() []Change {
 	unappliedChanges = []Change{}
 	return cpy
 }
+
+func Render(_ string) string {
+	if len(unappliedChanges) == 0 {
+		return "No valset changes to apply."
+	}
+
+	output := "Valset changes to apply:\n"
+	for _, change := range unappliedChanges {
+		output += "- " + string(change.Address) + " (" + strconv.Itoa(change.Power) + ")\n"
+	}
+	return output
+}