smartcontract: modernize Builder example

And make it a bit more useful.

pkg/smartcontract/doc_test.go

@@ -4,9 +4,10 @@ import (
 	"context"
 	"encoding/hex"
 
-	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/actor"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/gas"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/neo"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/wallet"
@@ -14,37 +15,48 @@ import (
 
 func ExampleBuilder() {
 	// No error checking done at all, intentionally.
+	w, _ := wallet.NewWalletFromFile("somewhere")
+	defer w.Close()
+
 	c, _ := rpcclient.New(context.Background(), "url", rpcclient.Options{})
-	neoHash, _ := c.GetNativeContractHash("NeoToken")
+
+	// Assuming there is one Account inside.
+	a, _ := actor.NewSimple(c, w.Accounts[0])
 
 	pKey, _ := hex.DecodeString("03d9e8b16bd9b22d3345d6d4cde31be1c3e1d161532e3d0ccecb95ece2eb58336e") // Public key.
 
 	b := smartcontract.NewBuilder()
-	// Single NEO "vote" call with a check
+	// Transfer + vote in a single script with each action leaving return value on the stack.
-	b.InvokeWithAssert(neoHash, "vote", pKey)
+	b.InvokeMethod(neo.Hash, "transfer", a.Sender(), util.Uint160{0xff}, 1, nil)
+	b.InvokeMethod(neo.Hash, "vote", pKey)
 	script, _ := b.Script()
 
-	// The script can then be used to create transaction or to invoke via RPC.
+	// Actor has an Invoker inside, so we can perform test invocation using the script.
-	res, _ := c.InvokeScript(script, []transaction.Signer{{Account: util.Uint160{0x01, 0x02, 0x03}, Scopes: transaction.CalledByEntry}})
+	res, _ := a.Run(script)
-	if res.State != "HALT" {
+	if res.State != "HALT" || len(res.Stack) != 2 {
-		// The script failed
+		// The script failed completely or didn't return proper number of return values.
+	}
+
+	transferResult, _ := res.Stack[0].TryBool()
+	voteResult, _ := res.Stack[1].TryBool()
+
+	if !transferResult {
+		// Transfer failed.
+	}
+	if !voteResult {
+		// Vote failed.
 	}
 
 	b.Reset() // Copy the old script above if you need it!
 
-	w, _ := wallet.NewWalletFromFile("somewhere")
+	// Multiple transfers of different tokens in a single script. If any of
-	defer w.Close()
+	// them fails whole script fails.
-	// Assuming there is one Account inside
+	b.InvokeWithAssert(neo.Hash, "transfer", a.Sender(), util.Uint160{0x70}, 1, nil)
-	a, _ := actor.NewSimple(c, w.Accounts[0])
+	b.InvokeWithAssert(gas.Hash, "transfer", a.Sender(), util.Uint160{0x71}, 100000, []byte("data"))
-	from := w.Accounts[0].Contract.ScriptHash() // Assuming Contract is present.
+	b.InvokeWithAssert(neo.Hash, "transfer", a.Sender(), util.Uint160{0x72}, 1, nil)
-
-	// Multiple transfers in a single script. If any of them fail whole script fails.
-	b.InvokeWithAssert(neoHash, "transfer", from, util.Uint160{0x70}, 1, nil)
-	b.InvokeWithAssert(neoHash, "transfer", from, util.Uint160{0x71}, 10, []byte("data"))
-	b.InvokeWithAssert(neoHash, "transfer", from, util.Uint160{0x72}, 1, nil)
 	script, _ = b.Script()
 
-	// The script can then be used to create transaction or to invoke via RPC.
+	// Now send a transaction with this script via an RPC node.
 	txid, vub, _ := a.SendRun(script)
 	_ = txid
 	_ = vub