Rename Variable* to Value*

- Rename MarshalVariable to MarshalValue
- Rename NewVariableEncoder to NewValueEncoder
- Rename VariableEncoder to ValueEncoder
- Rename VariableMarshaler to ValueMarshaler
- Rename MarshalTypstVariable to MarshalTypstValue

There are now wrappers which ensure compatibility with code that still uses some of the old functions/types.

- Improve image_test.go by adding an assertion
- Rename all occurrences of Variable to Value
- Remove "TODO: Handle images..." as that's already working with the image wrapper
- Update README.md

README.md

@@ -20,7 +20,7 @@ Use at your own discretion for production systems.
 
 - PDF, SVG and PNG generation.
 - All Typst parameters are discoverable and documented in [cli-options.go](cli-options.go).
-- Go-to-Typst Object Encoder: Seamlessly inject any Go values (Including `image.Image` with a [wrapper](image.go)) into Typst documents via the provided encoder.
+- Go-to-Typst Value Encoder: Seamlessly inject any Go values (Including `image.Image` with a [wrapper](image.go)) into Typst documents via the provided encoder.
 - Errors from Typst CLI are returned as structured Go error objects with detailed information, such as line numbers and file paths.
 - Uses stdio; No temporary files will be created.
 - Good unit test coverage.

examples/simple/main.go

@@ -12,7 +12,7 @@ import (
 
 func main() {
 	// Convert a time.Time value into Typst markup.
-	date, err := typst.MarshalVariable(time.Now())
+	date, err := typst.MarshalValue(time.Now())
 	if err != nil {
 		log.Panicf("Failed to marshal date into Typst markup: %v", err)
 	}

image.go

@@ -15,10 +15,10 @@ import (
 
 // Image can be used to encode any image.Image into a typst image.
 //
-// For this, just wrap any image.Image with this type before passing it to MarshalVariable or a VariableEncoder.
+// For this, just wrap any image.Image with this type before passing it to MarshalValue or a ValueEncoder.
 type Image struct{ image.Image }
 
-func (i Image) MarshalTypstVariable() ([]byte, error) {
+func (i Image) MarshalTypstValue() ([]byte, error) {
 	var buffer bytes.Buffer
 
 	if err := png.Encode(&buffer, i); err != nil {

image_test.go

@@ -48,7 +48,9 @@ func TestImage(t *testing.T) {
 
 	r.WriteString(`= Image test
 
-#TestImage`) // TODO: Add assertion for the image width and height as soon as it's possible to query that
+#TestImage
+
+#assert(type(TestImage) == content, message: "TestImage is not of expected type: got " + str(type(TestImage)) + ", want content")`) // TODO: Add another assertion for the image width and height as soon as it's possible to query that
 
 	if err := cli.Compile(&r, io.Discard, nil); err != nil {
 		t.Fatalf("Failed to compile document: %v.", err)

util.go

@@ -16,14 +16,14 @@ import (
 // This can be used to inject Go values into typst documents.
 //
 // Every key in values needs to be a valid identifier, otherwise this function will return an error.
-// Every value in values will be marshaled according to VariableEncoder into equivalent Typst markup.
+// Every value in values will be marshaled according to ValueEncoder into equivalent Typst markup.
 //
 // Passing {"foo": 1, "bar": 60 * time.Second} as values will produce the following output:
 //
 //	#let foo = 1
 //	#let bar = duration(seconds: 60)
 func InjectValues(output io.Writer, values map[string]any) error {
-	enc := NewVariableEncoder(output)
+	enc := NewValueEncoder(output)
 
 	// We will have to iterate over the sorted list of map keys.
 	// Otherwise the output is not deterministic, and tests will fail randomly.
@@ -36,7 +36,7 @@ func InjectValues(output io.Writer, values map[string]any) error {
 			return err
 		}
 		if err := enc.Encode(v); err != nil {
-			return fmt.Errorf("failed to encode variables with key %q: %w", k, err)
+			return fmt.Errorf("failed to encode values with key %q: %w", k, err)
 		}
 		if _, err := output.Write([]byte("\n")); err != nil {
 			return err

value-encoder.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2024 David Vogel
+// Copyright (c) 2024-2025 David Vogel
 //
 // This software is released under the MIT License.
 // https://opensource.org/licenses/MIT
@@ -18,11 +18,11 @@ import (
 	"time"
 )
 
-// MarshalVariable takes any go type and returns a typst markup representation as a byte slice.
+// MarshalValue takes any go type and returns a typst markup representation as a byte slice.
-func MarshalVariable(v any) ([]byte, error) {
+func MarshalValue(v any) ([]byte, error) {
 	var buf bytes.Buffer
 
-	enc := NewVariableEncoder(&buf)
+	enc := NewValueEncoder(&buf)
 	if err := enc.Encode(v); err != nil {
 		return nil, err
 	}
@@ -30,37 +30,37 @@ func MarshalVariable(v any) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-// VariableMarshaler can be implemented by types to support custom typst marshaling.
+// ValueMarshaler can be implemented by types to support custom Typst marshaling.
-type VariableMarshaler interface {
+type ValueMarshaler interface {
-	MarshalTypstVariable() ([]byte, error)
+	MarshalTypstValue() ([]byte, error)
 }
 
-type VariableEncoder struct {
+type ValueEncoder struct {
 	indentLevel int
 
 	writer io.Writer
 }
 
-// NewVariableEncoder returns a new encoder that writes into w.
+// NewValueEncoder returns a new encoder that writes into w.
-func NewVariableEncoder(w io.Writer) *VariableEncoder {
+func NewValueEncoder(w io.Writer) *ValueEncoder {
-	return &VariableEncoder{
+	return &ValueEncoder{
 		writer: w,
 	}
 }
 
-func (e *VariableEncoder) Encode(v any) error {
+func (e *ValueEncoder) Encode(v any) error {
 	return e.marshal(reflect.ValueOf(v))
 }
 
-func (e *VariableEncoder) writeString(s string) error {
+func (e *ValueEncoder) writeString(s string) error {
 	return e.writeBytes([]byte(s))
 }
 
-func (e *VariableEncoder) writeRune(r rune) error {
+func (e *ValueEncoder) writeRune(r rune) error {
 	return e.writeBytes([]byte{byte(r)})
 }
 
-func (e *VariableEncoder) writeStringLiteral(s []byte) error {
+func (e *ValueEncoder) writeStringLiteral(s []byte) error {
 	dst := make([]byte, 0, len(s)+5)
 
 	dst = append(dst, '"')
@@ -85,7 +85,7 @@ func (e *VariableEncoder) writeStringLiteral(s []byte) error {
 	return e.writeBytes(dst)
 }
 
-func (e *VariableEncoder) writeBytes(b []byte) error {
+func (e *ValueEncoder) writeBytes(b []byte) error {
 	if _, err := e.writer.Write(b); err != nil {
 		return fmt.Errorf("failed to write into writer: %w", err)
 	}
@@ -93,11 +93,11 @@ func (e *VariableEncoder) writeBytes(b []byte) error {
 	return nil
 }
 
-func (e *VariableEncoder) writeIndentationCharacters() error {
+func (e *ValueEncoder) writeIndentationCharacters() error {
 	return e.writeBytes(slices.Repeat([]byte{' ', ' '}, e.indentLevel))
 }
 
-func (e *VariableEncoder) marshal(v reflect.Value) error {
+func (e *ValueEncoder) marshal(v reflect.Value) error {
 	if !v.IsValid() {
 		return e.writeString("none")
 		//return fmt.Errorf("invalid reflect.Value %v", v)
@@ -134,8 +134,18 @@ func (e *VariableEncoder) marshal(v reflect.Value) error {
 		return nil
 	}
 
-	// TODO: Handle images, maybe create a wrapper type that does this
+	if t.Implements(reflect.TypeFor[ValueMarshaler]()) {
+		if m, ok := v.Interface().(ValueMarshaler); ok {
+			bytes, err := m.MarshalTypstValue()
+			if err != nil {
+				return fmt.Errorf("error calling MarshalTypstValue for type %s: %w", t.String(), err)
+			}
+			return e.writeBytes(bytes)
+		}
+		return e.writeString("none")
+	}
 
+	// TODO: Remove this in a future update, it's only here for compatibility reasons
 	if t.Implements(reflect.TypeFor[VariableMarshaler]()) {
 		if m, ok := v.Interface().(VariableMarshaler); ok {
 			bytes, err := m.MarshalTypstVariable()
@@ -222,11 +232,11 @@ func (e *VariableEncoder) marshal(v reflect.Value) error {
 	return err
 }
 
-func (e *VariableEncoder) encodeString(v reflect.Value) error {
+func (e *ValueEncoder) encodeString(v reflect.Value) error {
 	return e.writeStringLiteral([]byte(v.String()))
 }
 
-func (e *VariableEncoder) encodeStruct(v reflect.Value, t reflect.Type) error {
+func (e *ValueEncoder) encodeStruct(v reflect.Value, t reflect.Type) error {
 	if v.NumField() == 0 {
 		return e.writeString("()")
 	}
@@ -276,7 +286,7 @@ func (e *VariableEncoder) encodeStruct(v reflect.Value, t reflect.Type) error {
 	return e.writeRune(')')
 }
 
-func (e *VariableEncoder) resolveKeyName(v reflect.Value) (string, error) {
+func (e *ValueEncoder) resolveKeyName(v reflect.Value) (string, error) {
 	// From encoding/json/encode.go.
 	if v.Kind() == reflect.String {
 		return v.String(), nil
@@ -297,7 +307,7 @@ func (e *VariableEncoder) resolveKeyName(v reflect.Value) (string, error) {
 	return "", fmt.Errorf("unsupported map key type %q", v.Type().String())
 }
 
-func (e *VariableEncoder) encodeMap(v reflect.Value) error {
+func (e *ValueEncoder) encodeMap(v reflect.Value) error {
 	if v.Len() == 0 {
 		return e.writeString("()")
 	}
@@ -357,7 +367,7 @@ func (e *VariableEncoder) encodeMap(v reflect.Value) error {
 	return e.writeRune(')')
 }
 
-func (e *VariableEncoder) EncodeByteSlice(bb []byte) error {
+func (e *ValueEncoder) EncodeByteSlice(bb []byte) error {
 	if err := e.writeString("bytes(("); err != nil {
 		return err
 	}
@@ -385,7 +395,7 @@ func (e *VariableEncoder) EncodeByteSlice(bb []byte) error {
 	return e.writeString("))")
 }
 
-func (e *VariableEncoder) encodeSlice(v reflect.Value, t reflect.Type) error {
+func (e *ValueEncoder) encodeSlice(v reflect.Value, t reflect.Type) error {
 
 	// Special case for byte slices.
 	if t.Elem().Kind() == reflect.Uint8 {
@@ -417,7 +427,7 @@ func (e *VariableEncoder) encodeSlice(v reflect.Value, t reflect.Type) error {
 	return e.writeRune(')')
 }
 
-func (e *VariableEncoder) encodeArray(v reflect.Value) error {
+func (e *ValueEncoder) encodeArray(v reflect.Value) error {
 	if err := e.writeRune('('); err != nil {
 		return err
 	}
@@ -443,7 +453,7 @@ func (e *VariableEncoder) encodeArray(v reflect.Value) error {
 	return e.writeRune(')')
 }
 
-func (e *VariableEncoder) encodeTime(t time.Time) error {
+func (e *ValueEncoder) encodeTime(t time.Time) error {
 	return e.writeString(fmt.Sprintf("datetime(year: %d, month: %d, day: %d, hour: %d, minute: %d, second: %d)",
 		t.Year(),
 		t.Month(),
@@ -454,6 +464,6 @@ func (e *VariableEncoder) encodeTime(t time.Time) error {
 	))
 }
 
-func (e *VariableEncoder) encodeDuration(d time.Duration) error {
+func (e *ValueEncoder) encodeDuration(d time.Duration) error {
 	return e.writeString(fmt.Sprintf("duration(seconds: %d)", int(math.Round(d.Seconds()))))
 }

value-encoder_test.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2024 David Vogel
+// Copyright (c) 2024-2025 David Vogel
 //
 // This software is released under the MIT License.
 // https://opensource.org/licenses/MIT
@@ -18,7 +18,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 )
 
-func TestMarshalVariable(t *testing.T) {
+func TestMarshalValue(t *testing.T) {
 	tests := []struct {
 		name    string
 		arg     any
@@ -31,33 +31,33 @@ func TestMarshalVariable(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got, err := typst.MarshalVariable(tt.arg)
+			got, err := typst.MarshalValue(tt.arg)
 			if (err != nil) != tt.wantErr {
-				t.Errorf("MarshalVariable() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("MarshalValue() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("MarshalVariable() = %v, want %v", got, tt.want)
+				t.Errorf("MarshalValue() = %v, want %v", got, tt.want)
 			}
 		})
 	}
 }
 
-type VariableMarshalerType []byte
+type ValueMarshalerType []byte
 
-func (v VariableMarshalerType) MarshalTypstVariable() ([]byte, error) {
+func (v ValueMarshalerType) MarshalTypstValue() ([]byte, error) {
 	result := append([]byte{'"'}, v...)
 	result = append(result, '"')
 
 	return result, nil
 }
 
-type VariableMarshalerTypePointer []byte
+type ValueMarshalerTypePointer []byte
 
-var variableMarshalerTypePointer = VariableMarshalerTypePointer("test")
+var valueMarshalerTypePointer = ValueMarshalerTypePointer("test")
-var variableMarshalerTypePointerNil = VariableMarshalerTypePointer(nil)
+var valueMarshalerTypePointerNil = ValueMarshalerTypePointer(nil)
 
-func (v *VariableMarshalerTypePointer) MarshalTypstVariable() ([]byte, error) {
+func (v *ValueMarshalerTypePointer) MarshalTypstValue() ([]byte, error) {
 	if v != nil {
 		result := append([]byte{'"'}, *v...)
 		result = append(result, '"')
@@ -87,7 +87,7 @@ func (v *TextMarshalerTypePointer) MarshalText() ([]byte, error) {
 	return nil, fmt.Errorf("no data")
 }
 
-func TestVariableEncoder(t *testing.T) {
+func TestValueEncoder(t *testing.T) {
 
 	tests := []struct {
 		name    string
@@ -156,11 +156,11 @@ func TestVariableEncoder(t *testing.T) {
 		{"byte slice 1", []byte{1}, false, `bytes((1,))`},
 		{"byte slice empty", []byte{}, false, `bytes(())`},
 		{"byte slice nil", []byte(nil), false, `bytes(())`},
-		{"MarshalTypstVariable value", VariableMarshalerType("test"), false, `"test"`},
+		{"MarshalTypstValue value", ValueMarshalerType("test"), false, `"test"`},
-		{"MarshalTypstVariable value nil", VariableMarshalerType(nil), false, `""`},
+		{"MarshalTypstValue value nil", ValueMarshalerType(nil), false, `""`},
-		{"MarshalTypstVariable pointer", &variableMarshalerTypePointer, false, `"test"`},
+		{"MarshalTypstValue pointer", &valueMarshalerTypePointer, false, `"test"`},
-		{"MarshalTypstVariable pointer nil", &variableMarshalerTypePointerNil, false, `""`},
+		{"MarshalTypstValue pointer nil", &valueMarshalerTypePointerNil, false, `""`},
-		{"MarshalTypstVariable nil pointer", struct{ A *VariableMarshalerTypePointer }{nil}, true, ``},
+		{"MarshalTypstValue nil pointer", struct{ A *ValueMarshalerTypePointer }{nil}, true, ``},
 		{"MarshalText value", TextMarshalerType("test"), false, `"test"`},
 		{"MarshalText value nil", TextMarshalerType(nil), false, `""`},
 		{"MarshalText pointer", &textMarshalerTypePointer, false, `"test"`},
@@ -179,12 +179,12 @@ func TestVariableEncoder(t *testing.T) {
 			t.Parallel()
 
 			var result bytes.Buffer
-			vEnc := typst.NewVariableEncoder(&result)
+			vEnc := typst.NewValueEncoder(&result)
 
 			err := vEnc.Encode(tt.params)
 			switch {
 			case err != nil && !tt.wantErr:
-				t.Fatalf("Failed to encode typst variables: %v", err)
+				t.Fatalf("Failed to encode typst values: %v", err)
 			case err == nil && tt.wantErr:
 				t.Fatalf("Expected error, but got none")
 			}

variable-encoder-compat.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2025 David Vogel
+//
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+package typst
+
+import "io"
+
+// This exists for compatibility reasons.
+
+// Deprecated: Use NewValueEncoder instead, as this will be removed in a future version.
+func NewVariableEncoder(w io.Writer) *ValueEncoder { return NewValueEncoder(w) }
+
+// Deprecated: Use MarshalValue instead, as this will be removed in a future version.
+func MarshalVariable(v any) ([]byte, error) { return MarshalValue(v) }
+
+// Deprecated: Use ValueMarshaler interface instead, as this will be removed in a future version.
+type VariableMarshaler interface {
+	MarshalTypstVariable() ([]byte, error)
+}