brain: add method for new thinking approach

For #94.

Author: zephyrtronium

brain/brain.go

@@ -2,6 +2,7 @@ package brain
 
 import (
 	"context"
+	"iter"
 
 	"github.com/zephyrtronium/robot/message"
 	"github.com/zephyrtronium/robot/userhash"
@@ -17,11 +18,15 @@ type Interface interface {
 	// a different tuple has the empty string as its suffix to denote the end
 	// of the message. The positions of each in the argument are not guaranteed.
 	//
-	// Each tuple's prefix has entropy reduction transformations applied.
-	//
 	// Tuples in the argument may share storage for prefixes.
 	Learn(ctx context.Context, tag string, msg *Message, tuples []Tuple) error
 
+	// Think iterates all suffixes matching a prefix.
+	//
+	// Yielded closures replace id and suffix with successive messages' contents.
+	// The iterating loop may not call the yielded closure on every iteration.
+	Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id, suf *[]byte) error]
+
 	// Speak generates a full message and appends it to w.
 	//
 	// The prompt is in reverse order and has entropy reduction applied.

brain/braintest/braintest_test.go

@@ -2,6 +2,7 @@ package braintest_test
 
 import (
 	"context"
+	"iter"
 	"math/rand/v2"
 	"slices"
 	"strings"
@@ -76,6 +77,11 @@ func (m *membrain) Recall(ctx context.Context, tag string, page string, out []br
 	panic("unimplemented")
 }
 
+// Think implements brain.Interface.
+func (m *membrain) Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id *[]byte, suf *[]byte) error] {
+	panic("unimplemented")
+}
+
 func (m *membrain) Speak(ctx context.Context, tag string, prompt []string, w *brain.Builder) error {
 	m.mu.Lock()
 	defer m.mu.Unlock()

brain/kvbrain/speak.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"iter"
 	"math/rand/v2"
 
 	"github.com/dgraph-io/badger/v4"
@@ -15,6 +16,10 @@ import (
 
 var prependerPool tpool.Pool[deque.Deque[string]]
 
+func (m *Brain) Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id *[]byte, suf *[]byte) error] {
+	panic("unimplemented")
+}
+
 // Speak generates a full message and appends it to w.
 // The prompt is in reverse order and has entropy reduction applied.
 func (br *Brain) Speak(ctx context.Context, tag string, prompt []string, w *brain.Builder) error {

brain/learn_test.go

@@ -2,6 +2,7 @@ package brain_test
 
 import (
 	"context"
+	"iter"
 	"slices"
 	"strconv"
 	"testing"
@@ -32,6 +33,11 @@ func (t *testLearner) Speak(ctx context.Context, tag string, prompt []string, w
 	panic("unimplemented")
 }
 
+// Think implements brain.Interface.
+func (t *testLearner) Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id *[]byte, suf *[]byte) error] {
+	panic("unimplemented")
+}
+
 func (t *testLearner) Recall(ctx context.Context, tag string, page string, out []brain.Message) (n int, next string, err error) {
 	var k int
 	if page != "" {

brain/speak_test.go

@@ -2,6 +2,7 @@ package brain_test
 
 import (
 	"context"
+	"iter"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -18,6 +19,10 @@ type testSpeaker struct {
 	append []byte
 }
 
+func (t *testSpeaker) Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id *[]byte, suf *[]byte) error] {
+	panic("unimplemented")
+}
+
 func (t *testSpeaker) Speak(ctx context.Context, tag string, prompt []string, w *brain.Builder) error {
 	t.prompt = prompt
 	w.Append(t.id, t.append)

brain/sqlbrain/speak.go

@@ -3,6 +3,7 @@ package sqlbrain
 import (
 	"context"
 	"fmt"
+	"iter"
 	"math/rand/v2"
 
 	"zombiezen.com/go/sqlite"
@@ -14,6 +15,10 @@ import (
 
 var prependerPool tpool.Pool[deque.Deque[string]]
 
+func (br *Brain) Think(ctx context.Context, tag string, prefix []string) iter.Seq[func(id *[]byte, suf *[]byte) error] {
+	panic("unimplemented")
+}
+
 // Speak generates a full message and appends it to w.
 // The prompt is in reverse order and has entropy reduction applied.
 func (br *Brain) Speak(ctx context.Context, tag string, prompt []string, w *brain.Builder) error {