Demo changes

Makefile

@@ -1,93 +1,33 @@
-.PHONY: dev build cli server install image release profile compare bench test clean
+.PHONY: dev build install image profile bench test clean
 
 CGO_ENABLED=0
+COMMIT=$(shell git rev-parse --short HEAD)
 
-VERSION ?= $(shell git describe 2>/dev/null || echo "")
+all: dev
 
-DESTDIR ?= $(GOBIN)
+dev: build
+	@./monkey-lang -d
 
-ifeq ($(LOCAL), 1)
-IMAGE := r.mills.io/prologic/monkey
-TAG := dev
-else
-ifeq ($(BRANCH), master)
-IMAGE := prologic/monkey
-TAG := latest
-else
-IMAGE := prologic/monkey
-TAG := dev
-endif
-endif
-
-all: help
-
-help: ## Show this help message
-	@echo "monkey - Monkey Lang"
-	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m\033[0m\n"} /^[$$()% a-zA-Z_-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
-
-dev: cli ## Build monkey and run the REPL
-	@./monkey
-
-build: clean cli server  ## Build monkey
-
-cli: ## Build monkey CLI
+build: clean
 	@go build \
 		-tags "netgo static_build" -installsuffix netgo \
-		-ldflags "-w -X go.mills.io/monkey/v2.MonkeyVersion=$(VERSION)" \
-		./cmd/monkey/...
+		-ldflags "-w -X $(shell go list)/version/.GitCommit=$(COMMIT)" \
+		.
 
-server: ## Build Monkey server
-	@go build \
-		-tags "netgo static_build" -installsuffix netgo \
-		-ldflags "-w -X go.mills.io/monkey/v2.MonkeyVersion=$(VERSION)" \
-		./cmd/monkey-server/...
+install: build
+	@go install
 
-install: cli server ## Install monkey to $DESTDIR
-	@install -D -m 755 monkey $(DESTDIR)/monkey
-	@install -D -m 755 monkey-server $(DESTDIR)monkey-server
+image:
+	@docker build -t prologic/monkey-lang .
 
-ifeq ($(PUBLISH), 1)
-image: ## Build and Publish the Docker image
-	@docker buildx build \
-		--build-arg VERSION="$(VERSION)" \
-		--build-arg COMMIT="$(COMMIT)" \
-		--build-arg BUILD="$(BUILD)" \
-		--platform linux/amd64,linux/arm64 --push -t $(IMAGE):$(TAG) .
-else
-image: ## Build the Docker image
-	@docker build  \
-		--build-arg VERSION="$(VERSION)" -t $(IMAGE):$(TAG) .
-endif
-
-release: ## Release monkey
-	@./tools/release.sh
-
-profile: ## Run tests with profiling enabled
+profile:
 	@go test -cpuprofile cpu.prof -memprofile mem.prof -v -bench ./...
 
-compare: ## Run benchmarks comparing Monkey with other languages
-	@hyperfine -w 5 -p 'make build; gcc -o examples/fib examples/fib.c' \
-		-n c -n go -n tengo -n python -n tauc -n taugo -n monkey \
-		--sort mean-time --export-markdown Benchmark.md \
-		'./examples/fib' \
-		'go run examples/fib.go' \
-		'tengo examples/fib.tengo' \
-		'python3 examples/fib.py' \
-		'tauc examples/fib.tau' \
-		'taugo examples/fib.tau' \
-		'./monkey examples/fib.m'
-
-bench: # Run test benchmarks
+bench:
 	@go test -v -benchmem -bench=. ./...
 
-test: ## Run unit tests
-	@go test -v \
-		-cover \
-		-coverprofile coverage.out \
-		-covermode atomic \
-		-coverpkg ./... \
-		-race \
-		./...
+test:
+	@go test -v -cover -coverprofile=coverage.txt -covermode=atomic -coverpkg=./... -race ./...
 
-clean: ## Cleanup untrakced files
-	@git clean -f -d -X 2> /dev/null || true
+clean:
+	@git clean -f -d -X

code/code.go

@@ -10,6 +10,14 @@ type Instructions []byte
 
 type Opcode byte
 
+func (o Opcode) String() string {
+	def, err := Lookup(byte(o))
+	if err != nil {
+		return ""
+	}
+	return def.Name
+}
+
 const (
 	OpConstant Opcode = iota
 	OpAdd

examples/demo.monkey

@@ -40,4 +40,4 @@ let map = fn(arr, f) {
 };
 
 let numbers = [1, 1 + 1, 4 - 1, 2 * 2, 2 + 3, 12 / 2];
-map(numbers, fibonacci);
+//map(numbers, fibonacci);

examples/fact.monkey

@@ -0,0 +1,8 @@
+let fact = fn(n) {
+  if (n == 0) {
+    return 1
+  }
+  return n * fact(n - 1)
+}
+
+print(fact(5)

examples/factt.monkey

@@ -0,0 +1,8 @@
+	let fact = fn(n, a) {
+  if (n == 0) {
+    return a
+  }
+  return fact(n - 1, a * n)
+}
+
+print(fact(5, 1))

examples/hello.monkey

@@ -0,0 +1 @@
+print("Hello World!")

testdata/popbug1.monkey

@@ -0,0 +1 @@
+let n = 2; let x = 0; while (n > 0) { if (n > 1) { x = x + 1 }; n = n - 1; }; x;

testdata/popbug2.monkey

@@ -0,0 +1 @@
+let n = 2; let x = 0; while (n > 0) { if (n > 1) { x = x + 1 }; let n = n - 1; }; x;

testdata/popbug3.monkey

@@ -0,0 +1 @@
+let x = 1; if (x == 1) { let x = 2 }

vm/frame.go

@@ -21,3 +21,7 @@ func NewFrame(cl *object.Closure, basePointer int) *Frame {
 func (f *Frame) Instructions() code.Instructions {
 	return f.cl.Fn.Instructions
 }
+
+func (f *Frame) NextOp() code.Opcode {
+	return code.Opcode(f.Instructions()[f.ip+1])
+}

vm/vm.go

@@ -119,7 +119,11 @@ func (vm *VM) Run() error {
 			}
 
 		case code.OpPop:
+			// This makes things like this work:
+			// >> let x = 1; if (x == 1) { x = 2 }
+			if vm.sp > 0 {
 				vm.pop()
+			}
 
 		case code.OpTrue:
 			err := vm.push(True)
@@ -563,6 +567,19 @@ func (vm *VM) callClosure(cl *object.Closure, numArgs int) error {
 		return fmt.Errorf("wrong number of arguments: want=%d, got=%d", cl.Fn.NumParameters, numArgs)
 	}
 
+	// Optimize tail calls and avoid a new frame
+	if cl.Fn == vm.currentFrame().cl.Fn {
+		nextOP := vm.currentFrame().NextOp()
+		if nextOP == code.OpReturn {
+			for p := 0; p < numArgs; p++ {
+				vm.stack[vm.currentFrame().basePointer+p] = vm.stack[vm.sp-numArgs+p]
+			}
+			vm.sp -= numArgs + 1
+			vm.currentFrame().ip = -1 // reset IP to the beginning of the frame
+			return nil
+		}
+	}
+
 	frame := NewFrame(cl, vm.sp-numArgs)
 	vm.pushFrame(frame)
 	vm.sp = frame.basePointer + cl.Fn.NumLocals

vm/vm_test.go

@@ -833,6 +833,40 @@ func TestAssignmentStatements(t *testing.T) {
 	runVmTests(t, tests)
 }
 
+func TestTailCalls(t *testing.T) {
+	tests := []vmTestCase{
+		{
+			input: `
+			let fact = fn(n, a) {
+			  if (n == 0) {
+				return a
+			  }
+			  return fact(n - 1, a * n)
+			}
+
+			fact(5, 1)
+        	`,
+			expected: 120,
+		},
+
+		// without tail recursion optimization this will cause a stack overflow
+		{
+			input: `
+			let iter = fn(n, max) {
+				if (n == max) {
+					return n
+				}
+				return iter(n + 1, max)
+			}
+			iter(0, 9999)
+			`,
+			expected: 9999,
+		},
+	}
+
+	runVmTests(t, tests)
+}
+
 func TestIntegration(t *testing.T) {
 	matches, err := filepath.Glob("../testdata/*.monkey")
 	if err != nil {
@@ -874,42 +908,79 @@ func TestIntegration(t *testing.T) {
 	}
 }
 
-func TestExamples(t *testing.T) {
-	matches, err := filepath.Glob("../examples/*.monkey")
-	if err != nil {
-		t.Error(err)
+func BenchmarkFibonacci(b *testing.B) {
+	tests := map[string]string{
+		"iterative": `
+		let fib = fn(n) {
+		   if (n < 3) {
+			 return 1
+		   }
+		   let a = 1
+		   let b = 1
+		   let c = 0
+		   let i = 0
+		   while (i < n - 2) {
+			 c = a + b
+			 b = a
+			 a = c
+			 i = i + 1
+		   }
+		   return a
 		}
 
-	for _, match := range matches {
-		basename := path.Base(match)
-		name := strings.TrimSuffix(basename, filepath.Ext(basename))
-
-		t.Run(name, func(t *testing.T) {
-			b, err := os.ReadFile(match)
-			if err != nil {
-				t.Error(err)
+		fib(35)
+		`,
+		"recursive": `
+		let fib = fn(x) {
+		  if (x == 0) {
+			return 0
+		  }
+		  if (x == 1) {
+			return 1
+		  }
+		  return fib(x-1) + fib(x-2)
 		}
 
-			input := string(b)
+		fib(35)
+		`,
+		"tail-recursive": `
+		let fib = fn(n, a, b) {
+		  if (n == 0) {
+			return a
+		  }
+		  if (n == 1) {
+			return b
+		  }
+		  return fib(n - 1, b, a + b)
+		}
+
+		fib(35, 0, 1)
+		`,
+	}
+
+	for name, input := range tests {
+		b.Run(name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
 				program := parse(input)
 
 				c := compiler.New()
-			err = c.Compile(program)
+				err := c.Compile(program)
 				if err != nil {
-				t.Log(input)
-				t.Fatalf("compiler error: %s", err)
+					b.Log(input)
+					b.Fatalf("compiler error: %s", err)
 				}
 
 				vm := New(c.Bytecode())
 
 				err = vm.Run()
 				if err != nil {
-				t.Log(input)
-				t.Fatalf("vm error: %s", err)
+					b.Log(input)
+					b.Fatalf("vm error: %s", err)
 				}
 				if vm.sp != 0 {
-				t.Log(input)
-				t.Fatal("vm stack pointer non-zero")
+					b.Log(input)
+					b.Fatal("vm stack pointer non-zero")
+				}
 			}
 		})
 	}