Added base64, image.png, wasm data: to image, (limited) support for namespaces (virtual map access). moved the image functions under image.* (#217)

* Add (limited) support for namespaces (virtual map access). move the image function under image.*

* self review updates

* adding missing empty ns map

* revert the real namespace map, just use toplevel and hack lookup

* further reduce the diff

* Adding base64() and image.png() and looking for data: prefix in wasm for image producing

* linter...

* fixed #204 🎉

* format document and clear image to 1 pixel transparent gif when it goes back to empty

Author: ldemailly

Makefile

@@ -37,7 +37,7 @@ TINYGO_STACKS:=-stack-size=40mb
 
 wasm: Makefile *.go */*.go $(GEN) wasm/wasm_exec.js wasm/wasm_exec.html wasm/grol_wasm.html
 #	GOOS=wasip1 GOARCH=wasm go build -o grol.wasm -trimpath -ldflags="-w -s" -tags "$(GO_BUILD_TAGS)" .
-	GOOS=js GOARCH=wasm go build -o wasm/grol.wasm -trimpath -ldflags="-w -s" -tags "$(GO_BUILD_TAGS)" ./wasm
+	GOOS=js GOARCH=wasm $(WASM_GO) build -o wasm/grol.wasm -trimpath -ldflags="-w -s" -tags "$(GO_BUILD_TAGS)" ./wasm
 #	GOOS=wasip1 GOARCH=wasm tinygo build -target=wasi -no-debug -o grol_tiny.wasm -tags "$(GO_BUILD_TAGS)" .
 # Tiny go generates errors https://github.com/tinygo-org/tinygo/issues/1140
 #	GOOS=js GOARCH=wasm tinygo build $(TINYGO_STACKS) -no-debug -o wasm/grol.wasm -tags "$(GO_BUILD_TAGS)" ./wasm
@@ -50,11 +50,15 @@ wasm: Makefile *.go */*.go $(GEN) wasm/wasm_exec.js wasm/wasm_exec.html wasm/gro
 	sleep 3
 	open http://localhost:8080/
 
+
+#WASM_GO:=/opt/homebrew/Cellar/go/1.23.1/bin/go
+WASM_GO:=go
+
 GIT_TAG=$(shell git describe --tags --always --dirty)
 # used to copy to site a release version
 wasm-release: Makefile *.go */*.go $(GEN) wasm/wasm_exec.js wasm/wasm_exec.html
 	@echo "Building wasm release GIT_TAG=$(GIT_TAG)"
-	GOOS=js GOARCH=wasm go install -trimpath -ldflags="-w -s" -tags "$(GO_BUILD_TAGS)" grol.io/grol/wasm@$(GIT_TAG)
+	GOOS=js GOARCH=wasm $(WASM_GO) install -trimpath -ldflags="-w -s" -tags "$(GO_BUILD_TAGS)" grol.io/grol/wasm@$(GIT_TAG)
 	# No buildinfo and no tinygo install so we set version old style:
 #	GOOS=js GOARCH=wasm tinygo build $(TINYGO_STACKS) -o wasm/grol.wasm -no-debug -ldflags="-X main.TinyGoVersion=$(GIT_TAG)" -tags  "$(GO_BUILD_TAGS)" ./wasm
 	mv "$(shell go env GOPATH)/bin/js_wasm/wasm" wasm/grol.wasm
@@ -67,10 +71,10 @@ install:
 
 wasm/wasm_exec.js: Makefile
 #	cp "$(shell tinygo env TINYGOROOT)/targets/wasm_exec.js" ./wasm/
-	cp "$(shell go env GOROOT)/misc/wasm/wasm_exec.js" ./wasm/
+	cp "$(shell $(WASM_GO) env GOROOT)/misc/wasm/wasm_exec.js" ./wasm/
 
 wasm/wasm_exec.html:
-	cp "$(shell go env GOROOT)/misc/wasm/wasm_exec.html" ./wasm/
+	cp "$(shell $(WASM_GO) env GOROOT)/misc/wasm/wasm_exec.html" ./wasm/
 
 test: grol
 	CGO_ENABLED=0 go test -tags $(GO_BUILD_TAGS) ./...

eval/eval.go

@@ -292,6 +292,15 @@ func (s *State) evalInternal(node any) object.Object { //nolint:funlen,gocognit,
 	case *ast.MapLiteral:
 		return s.evalMapLiteral(node)
 	case *ast.IndexExpression:
+		if node.Value().Type() == token.DOT {
+			// See commits in PR#217 for a version using double map lookup, trading off the string concat (alloc)
+			// for a map lookup. code is a lot simpler without actual ns map though so we stick to this version
+			// for now.
+			extName := node.Left.Value().Literal() + "." + node.Index.Value().Literal()
+			if ext, ok := s.Extensions[extName]; ok {
+				return ext
+			}
+		}
 		return s.evalIndexExpression(s.Eval(node.Left), node)
 	case *ast.Comment:
 		return object.NULL

eval/eval_api.go

@@ -33,7 +33,7 @@ type State struct {
 	env        *object.Environment
 	rootEnv    *object.Environment // same as ancestor of env but used for reset in panic recovery.
 	cache      Cache
-	Extensions map[string]object.Extension
+	Extensions object.ExtensionMap
 	NoLog      bool // turn log() into println() (for EvalString)
 	// Max depth / recursion level - default DefaultMaxDepth,
 	// note that a simple function consumes at least 2 levels and typically at least 3 or 4.

examples/image.gr

@@ -18,7 +18,7 @@ func ycbcr(angle) {
 
 size = 1024
 imgName = "canvas"
-canvas = image(imgName, size, size)
+canvas = image.new(imgName, size, size)
 div = 6
 
 t = 0
@@ -29,15 +29,15 @@ for t < 12*PI {
 	y = cos(t) * (pow(E, cos(t)) - 2*cos(4*t) - pow(sin(t/12), 5))
 	angle := int(t*180./PI) % 360 // so ycbr() get memoized with 360 values
 	color = ycbcr(angle)
-	image_set_ycbcr(canvas, int(size/2+(size/div)*x+0.5), int(size/2.5+(size/div)*y+0.5), color)
+	image.set_ycbcr(canvas, int(size/2+(size/div)*x+0.5), int(size/2.5+(size/div)*y+0.5), color)
 	// Or in HSL:
 	// color[0] = t/(12*PI) // hue
 	// image_set_hsl(canvas, int(size/2+(size/div)*x+0.5), int(size/2.5+(size/div)*y+0.5), color)
-	t = t + 0.0005
+	t = t + 0.0005 // 0.0001 for profiling.
 }
 elapsed = time() - now
 log("Time elapsed: ", elapsed, " seconds")
 
-image_save(imgName)
+image.save(imgName)
 
 println("Saved image to grol.png")

extensions/extension.go

@@ -4,6 +4,7 @@ package extensions
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -373,6 +374,28 @@ func createMisc() {
 		},
 	}
 	MustCreate(intFn)
+	intFn.Name = "base64"
+	intFn.Callback = func(st any, _ string, args []object.Object) object.Object {
+		s := st.(*eval.State)
+		o := args[0]
+		var data []byte
+		switch o.Type() {
+		case object.REFERENCE:
+			ref := o.(object.Reference)
+			if ref.Value().Type() != object.STRING {
+				return s.Errorf("cannot convert ref to %s to base64", ref.Value().Type())
+			}
+			data = []byte(ref.Value().(object.String).Value)
+		case object.STRING:
+			data = []byte(o.(object.String).Value)
+		default:
+			return s.Errorf("cannot convert %s to base64", o.Type())
+		}
+		encoded := make([]byte, base64.StdEncoding.EncodedLen(len(data)))
+		base64.StdEncoding.Encode(encoded, data)
+		return object.String{Value: string(encoded)}
+	}
+	MustCreate(intFn)
 }
 
 func createTimeFunctions() {

extensions/images.go

@@ -1,6 +1,7 @@
 package extensions
 
 import (
+	"bytes"
 	"image"
 	"image/color"
 	"image/draw"
@@ -156,11 +157,11 @@ func ycbrArrayToRBGAColor(arr []object.Object) (color.RGBA, *object.Error) {
 	return rgba, nil
 }
 
-func createImageFunctions() {
+func createImageFunctions() { //nolint:funlen // this is a group of related functions.
 	// All the functions consistently use args[0] as the image name/reference into the ClientData map.
 	cdata := make(ImageMap)
 	imgFn := object.Extension{
-		Name:       "image",
+		Name:       "image.new",
 		MinArgs:    3,
 		MaxArgs:    3,
 		Help:       "create a new RGBA image of the name and size, image starts entirely transparent",
@@ -184,7 +185,7 @@ func createImageFunctions() {
 		},
 	}
 	MustCreate(imgFn)
-	imgFn.Name = "image_set"
+	imgFn.Name = "image.set"
 	imgFn.Help = "img, x, y, color: set a pixel in the named image, color is an array of 3 or 4 elements 0-255"
 	imgFn.MinArgs = 4
 	imgFn.MaxArgs = 4
@@ -201,11 +202,11 @@ func createImageFunctions() {
 		var color color.RGBA
 		var oerr *object.Error
 		switch name {
-		case "image_set_ycbcr":
+		case "image.set_ycbcr":
 			color, oerr = ycbrArrayToRBGAColor(colorArray)
-		case "image_set_hsl":
+		case "image.set_hsl":
 			color, oerr = hslArrayToRBGAColor(colorArray)
-		case "image_set":
+		case "image.set":
 			color, oerr = rgbArrayToRBGAColor(colorArray)
 		default:
 			return object.Errorf("unknown image_set function %q", name)
@@ -217,13 +218,13 @@ func createImageFunctions() {
 		return args[0]
 	}
 	MustCreate(imgFn)
-	imgFn.Name = "image_set_ycbcr"
+	imgFn.Name = "image.set_ycbcr"
 	imgFn.Help = "img, x, y, color: set a pixel in the named image, color Y'CbCr in an array of 3 elements 0-255"
 	MustCreate(imgFn)
-	imgFn.Name = "image_set_hsl"
+	imgFn.Name = "image.set_hsl"
 	imgFn.Help = "img, x, y, color: set a pixel in the named image, color in an array [Hue (0-360), Sat (0-1), Light (0-1)]"
 	MustCreate(imgFn)
-	imgFn.Name = "image_save"
+	imgFn.Name = "image.save"
 	imgFn.Help = "save the named image grol.png"
 	imgFn.MinArgs = 1
 	imgFn.MaxArgs = 1
@@ -246,4 +247,23 @@ func createImageFunctions() {
 		return args[0]
 	}
 	MustCreate(imgFn)
+	imgFn.Name = "image.png"
+	imgFn.Help = "returns the png data of the named image, suitable for base64"
+	imgFn.MinArgs = 1
+	imgFn.MaxArgs = 1
+	imgFn.ArgTypes = []object.Type{object.STRING}
+	imgFn.Callback = func(cdata any, _ string, args []object.Object) object.Object {
+		images := cdata.(ImageMap)
+		img, ok := images[args[0]]
+		if !ok {
+			return object.Errorf("image not found")
+		}
+		buf := bytes.Buffer{}
+		err := png.Encode(&buf, img)
+		if err != nil {
+			return object.Errorf("error encoding image: %v", err)
+		}
+		return object.String{Value: buf.String()}
+	}
+	MustCreate(imgFn)
 }

object/interp.go

@@ -2,22 +2,40 @@ package object
 
 import (
 	"errors"
+	"fmt"
+	"strings"
+
+	"grol.io/grol/lexer"
 )
 
+type ExtensionMap map[string]Extension
+
 var (
-	extraFunctions   map[string]Extension
+	extraFunctions   ExtensionMap
 	extraIdentifiers map[string]Object
 	initDone         bool
 )
 
 // Init resets the table of extended functions to empty.
 // Optional, will be called on demand the first time through CreateFunction.
 func Init() {
-	extraFunctions = make(map[string]Extension)
+	extraFunctions = make(ExtensionMap)
 	extraIdentifiers = make(map[string]Object)
 	initDone = true
 }
 
+func ValidIdentifier(name string) bool {
+	if name == "" {
+		return false
+	}
+	for _, b := range []byte(name) {
+		if !lexer.IsAlphaNum(b) {
+			return false
+		}
+	}
+	return true
+}
+
 // CreateFunction adds a new function to the table of extended functions.
 func CreateFunction(cmd Extension) error {
 	if !initDone {
@@ -26,6 +44,19 @@ func CreateFunction(cmd Extension) error {
 	if cmd.Name == "" {
 		return errors.New("empty command name")
 	}
+	// Only support 1 level of namespace for now.
+	dotSplit := strings.SplitN(cmd.Name, ".", 2)
+	var ns string
+	name := cmd.Name
+	if len(dotSplit) == 2 {
+		ns, name = dotSplit[0], dotSplit[1]
+		if !ValidIdentifier(ns) {
+			return fmt.Errorf("namespace %q not alphanumeric", ns)
+		}
+	}
+	if !ValidIdentifier(name) {
+		return errors.New(name + ": not alphanumeric")
+	}
 	if cmd.MaxArgs != -1 && cmd.MinArgs > cmd.MaxArgs {
 		return errors.New(cmd.Name + ": min args > max args")
 	}
@@ -36,13 +67,17 @@ func CreateFunction(cmd Extension) error {
 		return errors.New(cmd.Name + ": already defined")
 	}
 	cmd.Variadic = (cmd.MaxArgs == -1) || (cmd.MaxArgs > cmd.MinArgs)
+	// If namespaced, put both at top level (for sake of baseinfo and command completion) and
+	// in namespace map (for access/ref by eval). We decided to not even have namespaces map
+	// after all.
 	extraFunctions[cmd.Name] = cmd
 	return nil
 }
 
 // Returns the table of extended functions to seed the state of an eval.
-func ExtraFunctions() map[string]Extension {
-	return extraFunctions // no need to make a copy as each value need to be set to be changed (map of structs, not pointers).
+func ExtraFunctions() ExtensionMap {
+	// no need to make a copy as each value need to be set to be changed (map of structs, not pointers).
+	return extraFunctions
 }
 
 func IsExtraFunction(name string) bool {

repl/repl.go

@@ -380,6 +380,7 @@ func EvalOne(ctx context.Context, s *eval.State, what string, out io.Writer, opt
 		}()
 	}
 	s.SetContext(ctx, options.MaxDuration)
+	defer s.Cancel()
 	continuation, errs, formatted = evalOne(s, what, out, options)
 	return
 }