feat: observer pattern for statistics

internal/executer/executer.go

@@ -3,47 +3,37 @@ package executer
 import (
 	"fmt"
 	"log/slog"
-	"time"
 
 	"git.maximhutz.com/max/lambda/internal/config"
+	"git.maximhutz.com/max/lambda/pkg/emitter"
 	"git.maximhutz.com/max/lambda/pkg/lambda"
 )
 
 type Executor struct {
 	Config *config.Config
+	emitter.Emitter[*lambda.Expression]
 }
 
 func New(config *config.Config) *Executor {
 	return &Executor{Config: config}
 }
 
-func (e Executor) Run(expr *lambda.Expression) (*Results, error) {
-	results := &Results{}
-
-	if e.Config.Profile != "" {
-		profiler := Profiler{File: e.Config.Profile}
-		if err := profiler.Start(); err != nil {
-			return nil, err
-		}
-		defer profiler.End()
-	}
-
-	start := time.Now()
+func (e Executor) Run(expr *lambda.Expression) {
+	e.Emit("start", expr)
 
 	if e.Config.Explanation {
 		fmt.Println(lambda.Stringify(*expr))
 	}
 
 	for lambda.ReduceOnce(expr) {
+		e.Emit("step", expr)
 		if e.Config.Verbose {
 			slog.Info("reduction", "tree", lambda.Stringify(*expr))
 		}
 		if e.Config.Explanation {
 			fmt.Println("    =", lambda.Stringify(*expr))
 		}
-		results.StepsTaken++
 	}
 
-	results.TimeElapsed = uint64(time.Since(start).Milliseconds())
-	return results, nil
+	e.Emit("end", expr)
 }

internal/executer/profiler.go

@@ -1,40 +0,0 @@
-package executer
-
-import (
-	"os"
-	"path/filepath"
-	"runtime/pprof"
-)
-
-type Profiler struct {
-	File        string
-	filePointer *os.File
-}
-
-func (p *Profiler) Start() error {
-	absPath, err := filepath.Abs(p.File)
-	if err != nil {
-		return err
-	}
-
-	err = os.MkdirAll(filepath.Dir(absPath), 0777)
-	if err != nil {
-		return err
-	}
-
-	p.filePointer, err = os.Create(absPath)
-	if err != nil {
-		return err
-	}
-
-	if err = pprof.StartCPUProfile(p.filePointer); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (p *Profiler) End() {
-	pprof.StopCPUProfile()
-	p.filePointer.Close()
-}

internal/profiler/profiler.go

@@ -0,0 +1,48 @@
+package profiler
+
+import (
+	"os"
+	"path/filepath"
+	"runtime/pprof"
+
+	"git.maximhutz.com/max/lambda/pkg/lambda"
+)
+
+type Profiler struct {
+	File        string
+	filePointer *os.File
+	Error       error
+}
+
+func New(file string) *Profiler {
+	return &Profiler{File: file}
+}
+
+func (p *Profiler) Start(*lambda.Expression) {
+	var absPath string
+
+	absPath, p.Error = filepath.Abs(p.File)
+	if p.Error != nil {
+		return
+	}
+
+	p.Error = os.MkdirAll(filepath.Dir(absPath), 0777)
+	if p.Error != nil {
+		return
+	}
+
+	p.filePointer, p.Error = os.Create(absPath)
+	if p.Error != nil {
+		return
+	}
+
+	p.Error = pprof.StartCPUProfile(p.filePointer)
+	if p.Error != nil {
+		return
+	}
+}
+
+func (p *Profiler) End(*lambda.Expression) {
+	pprof.StopCPUProfile()
+	p.filePointer.Close()
+}

internal/statistics/results.go

@@ -1,4 +1,4 @@
-package executer
+package statistics
 
 import (
 	"fmt"

internal/statistics/statistics.go

@@ -0,0 +1,30 @@
+package statistics
+
+import (
+	"time"
+
+	"git.maximhutz.com/max/lambda/pkg/lambda"
+)
+
+type Profiler struct {
+	start   time.Time
+	steps   uint64
+	Results *Results
+}
+
+func (p *Profiler) Start(*lambda.Expression) {
+	p.start = time.Now()
+	p.steps = 0
+	p.Results = nil
+}
+
+func (p *Profiler) Step(*lambda.Expression) {
+	p.steps++
+}
+
+func (p *Profiler) End(*lambda.Expression) {
+	p.Results = &Results{
+		StepsTaken:  p.steps,
+		TimeElapsed: uint64(time.Since(p.start).Milliseconds()),
+	}
+}