Fix typst syntax with VariableEncoder

- Arrays with a single entry need a trailing comma
- Add writeRune method
- Negative numbers need to be put in code brackets, otherwise the typst parser will complain in some cases
- Add/change unit tests
- Let TestVariableEncoder test compile generated markup
- Update README.md

README.md

@@ -14,11 +14,11 @@ The supported and tested versions right now are:
 
 ## Features
 
-- PDF, SVG or PNG generation.
-- All typst-cli parameters are available as a struct, which makes it easy to discover all available options.
+- PDF, SVG and PNG generation.
+- All typst-cli parameters are [available as a struct](cli-options.go), which makes it easy to discover all available options.
 - Encoder to convert go values into typst markup which can be injected into typst documents.
 - Any stderr will be returned as go error value, including line number, column and file path of the error.
-- Uses stdio; No temporary files need to be created.
+- Uses stdio; No temporary files will be created.
 - Good unit test coverage.
 
 ## Installation

variable-encoder.go

@@ -16,6 +16,8 @@ import (
 	"time"
 )
 
+// TODO: Add simple marshal function that returns a byte slice
+
 // VariableMarshaler can be implemented by types to support custom typst marshaling.
 type VariableMarshaler interface {
 	MarshalTypstVariable() ([]byte, error)
@@ -42,6 +44,10 @@ func (e *VariableEncoder) writeString(s string) error {
 	return e.writeBytes([]byte(s))
 }
 
+func (e *VariableEncoder) writeRune(r rune) error {
+	return e.writeBytes([]byte{byte(r)})
+}
+
 func (e *VariableEncoder) writeStringLiteral(s []byte) error {
 	dst := make([]byte, 0, len(s)+5)
 
@@ -147,7 +153,19 @@ func (e *VariableEncoder) marshal(v reflect.Value) error {
 	case reflect.Bool:
 		err = e.writeString(strconv.FormatBool(v.Bool()))
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		err = e.writeString(strconv.FormatInt(v.Int(), 10))
+		if v.Int() >= 0 {
+			err = e.writeString(strconv.FormatInt(v.Int(), 10))
+		} else {
+			if err = e.writeRune('{'); err != nil {
+				break
+			}
+			if err = e.writeString(strconv.FormatInt(v.Int(), 10)); err != nil {
+				break
+			}
+			if err = e.writeRune('}'); err != nil {
+				break
+			}
+		}
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 		err = e.writeString(strconv.FormatUint(v.Uint(), 10))
 	case reflect.Float32, reflect.Float64:
@@ -158,7 +176,17 @@ func (e *VariableEncoder) marshal(v reflect.Value) error {
 		case math.IsInf(f, 1):
 			err = e.writeString("float.inf")
 		case math.IsInf(f, -1):
-			err = e.writeString("-float.inf")
+			err = e.writeString("{-float.inf}")
+		case math.Signbit(f):
+			if err = e.writeRune('{'); err != nil {
+				break
+			}
+			if err = e.writeString(strconv.FormatFloat(f, 'e', -1, 64)); err != nil {
+				break
+			}
+			if err = e.writeRune('}'); err != nil {
+				break
+			}
 		default:
 			err = e.writeString(strconv.FormatFloat(f, 'e', -1, 64))
 		}
@@ -224,7 +252,7 @@ func (e *VariableEncoder) encodeStruct(v reflect.Value, t reflect.Type) error {
 		return err
 	}
 
-	return e.writeString(")")
+	return e.writeRune(')')
 }
 
 func (e *VariableEncoder) resolveKeyName(v reflect.Value) (string, error) {
@@ -290,7 +318,7 @@ func (e *VariableEncoder) encodeMap(v reflect.Value) error {
 		return err
 	}
 
-	return e.writeString(")")
+	return e.writeRune(')')
 }
 
 func (e *VariableEncoder) EncodeByteSlice(bb []byte) error {
@@ -312,6 +340,12 @@ func (e *VariableEncoder) EncodeByteSlice(bb []byte) error {
 		}
 	}
 
+	if len(bb) == 1 {
+		if err := e.writeRune(','); err != nil {
+			return err
+		}
+	}
+
 	return e.writeString("))")
 }
 
@@ -322,7 +356,7 @@ func (e *VariableEncoder) encodeSlice(v reflect.Value, t reflect.Type) error {
 		return e.EncodeByteSlice(v.Bytes())
 	}
 
-	if err := e.writeString("("); err != nil {
+	if err := e.writeRune('('); err != nil {
 		return err
 	}
 
@@ -338,11 +372,17 @@ func (e *VariableEncoder) encodeSlice(v reflect.Value, t reflect.Type) error {
 		}
 	}
 
-	return e.writeString(")")
+	if n == 1 {
+		if err := e.writeRune(','); err != nil {
+			return err
+		}
+	}
+
+	return e.writeRune(')')
 }
 
 func (e *VariableEncoder) encodeArray(v reflect.Value) error {
-	if err := e.writeString("("); err != nil {
+	if err := e.writeRune('('); err != nil {
 		return err
 	}
 
@@ -358,7 +398,13 @@ func (e *VariableEncoder) encodeArray(v reflect.Value) error {
 		}
 	}
 
-	return e.writeString(")")
+	if n == 1 {
+		if err := e.writeRune(','); err != nil {
+			return err
+		}
+	}
+
+	return e.writeRune(')')
 }
 
 func (e *VariableEncoder) encodeTime(t time.Time) error {

variable-encoder_test.go

@@ -3,22 +3,27 @@
 // This software is released under the MIT License.
 // https://opensource.org/licenses/MIT
 
-package typst
+package typst_test
 
 import (
 	"bytes"
 	"fmt"
 	"math"
+	"strings"
 	"testing"
 	"time"
 
+	"github.com/Dadido3/go-typst"
 	"github.com/google/go-cmp/cmp"
 )
 
 type VariableMarshalerType []byte
 
 func (v VariableMarshalerType) MarshalTypstVariable() ([]byte, error) {
-	return v, nil
+	result := append([]byte{'"'}, v...)
+	result = append(result, '"')
+
+	return result, nil
 }
 
 type VariableMarshalerTypePointer []byte
@@ -28,7 +33,10 @@ var variableMarshalerTypePointerNil = VariableMarshalerTypePointer(nil)
 
 func (v *VariableMarshalerTypePointer) MarshalTypstVariable() ([]byte, error) {
 	if v != nil {
-		return *v, nil
+		result := append([]byte{'"'}, *v...)
+		result = append(result, '"')
+
+		return result, nil
 	}
 
 	return nil, fmt.Errorf("no data")
@@ -64,11 +72,16 @@ func TestVariableEncoder(t *testing.T) {
 		{"nil", nil, false, "none"},
 		{"bool false", false, false, "false"},
 		{"bool true", true, false, "true"},
-		{"int", int(-123), false, "-123"},
-		{"int8", int8(-123), false, "-123"},
-		{"int16", int16(-123), false, "-123"},
-		{"int32", int32(-123), false, "-123"},
-		{"int64", int64(-123), false, "-123"},
+		{"int", int(123), false, "123"},
+		{"int8", int8(123), false, "123"},
+		{"int16", int16(123), false, "123"},
+		{"int32", int32(123), false, "123"},
+		{"int64", int64(123), false, "123"},
+		{"int negative", int(-123), false, "{-123}"},
+		{"int8 negative", int8(-123), false, "{-123}"},
+		{"int16 negative", int16(-123), false, "{-123}"},
+		{"int32 negative", int32(-123), false, "{-123}"},
+		{"int64 negative", int64(-123), false, "{-123}"},
 		{"uint", uint(123), false, "123"},
 		{"uint8", uint8(123), false, "123"},
 		{"uint16", uint16(123), false, "123"},
@@ -76,11 +89,13 @@ func TestVariableEncoder(t *testing.T) {
 		{"uint64", uint64(123), false, "123"},
 		{"float32", float32(1), false, "1e+00"},
 		{"float64", float64(1), false, "1e+00"},
+		{"float32 negative", float32(-1), false, "{-1e+00}"},
+		{"float64 negative", float64(-1), false, "{-1e+00}"},
 		{"float64 nan", float64(math.NaN()), false, "float.nan"},
 		{"float64 +inf", float64(math.Inf(1)), false, "float.inf"},
-		{"float64 -inf", float64(math.Inf(-1)), false, "-float.inf"},
+		{"float64 -inf", float64(math.Inf(-1)), false, "{-float.inf}"},
 		{"string", "Hey!", false, `"Hey!"`},
-		{"string escaped", "Hey!😀 \"This is quoted\"\nNew line!", false, `"Hey!😀 \"This is quoted\"\nNew line!"`},
+		{"string escaped", "Hey!😀 \"This is quoted\"\nNew line!\tAnd a tab", false, `"Hey!😀 \"This is quoted\"\nNew line!\tAnd a tab"`},
 		{"struct", struct {
 			Foo string
 			Bar int
@@ -91,16 +106,20 @@ func TestVariableEncoder(t *testing.T) {
 		{"map string string empty", map[string]string{}, false, "()"},
 		{"map string string nil", map[string]string(nil), false, "()"},
 		{"string array", [5]string{"Foo", "Bar"}, false, `("Foo", "Bar", "", "", "")`},
+		{"string array 1", [1]string{"Foo"}, false, `("Foo",)`},
 		{"string slice", []string{"Foo", "Bar"}, false, `("Foo", "Bar")`},
+		{"string slice 1", []string{"Foo"}, false, `("Foo",)`},
 		{"string slice empty", []string{}, false, `()`},
 		{"string slice nil", []string(nil), false, `()`},
 		{"string slice pointer", &[]string{"Foo", "Bar"}, false, `("Foo", "Bar")`},
 		{"int slice", []int{1, 2, 3, 4, 5}, false, `(1, 2, 3, 4, 5)`},
+		{"int slice negative", []int{1, -2, 3, -4, 5}, false, `(1, {-2}, 3, {-4}, 5)`},
 		{"byte slice", []byte{1, 2, 3, 4, 5}, false, `bytes((1, 2, 3, 4, 5))`},
-		{"MarshalTypstVariable value", VariableMarshalerType("test"), false, "test"},
-		{"MarshalTypstVariable value nil", VariableMarshalerType(nil), false, ""},
-		{"MarshalTypstVariable pointer", &variableMarshalerTypePointer, false, "test"},
-		{"MarshalTypstVariable pointer nil", &variableMarshalerTypePointerNil, false, ""},
+		{"byte slice 1", []byte{1}, false, `bytes((1,))`},
+		{"MarshalTypstVariable value", VariableMarshalerType("test"), false, `"test"`},
+		{"MarshalTypstVariable value nil", VariableMarshalerType(nil), false, `""`},
+		{"MarshalTypstVariable pointer", &variableMarshalerTypePointer, false, `"test"`},
+		{"MarshalTypstVariable pointer nil", &variableMarshalerTypePointerNil, false, `""`},
 		{"MarshalTypstVariable nil pointer", struct{ A *VariableMarshalerTypePointer }{nil}, true, ``},
 		{"MarshalText value", TextMarshalerType("test"), false, `"test"`},
 		{"MarshalText value nil", TextMarshalerType(nil), false, `""`},
@@ -113,12 +132,14 @@ func TestVariableEncoder(t *testing.T) {
 		{"time.Duration", 60 * time.Second, false, `duration(seconds: 60)`},
 		{"time.Duration pointer", &[]time.Duration{60 * time.Second}[0], false, `duration(seconds: 60)`},
 		{"time.Duration pointer nil", (*time.Duration)(nil), false, `none`},
+		{"time.Duration negative", -60 * time.Second, false, `duration(seconds: -60)`},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
 
-			result := bytes.Buffer{}
-			vEnc := NewVariableEncoder(&result)
+			var result bytes.Buffer
+			vEnc := typst.NewVariableEncoder(&result)
 
 			err := vEnc.Encode(tt.params)
 			switch {
@@ -131,6 +152,16 @@ func TestVariableEncoder(t *testing.T) {
 			if !tt.wantErr && !cmp.Equal(result.String(), tt.want) {
 				t.Errorf("Got the following diff in output: %s", cmp.Diff(tt.want, result.String()))
 			}
+
+			// Compile to test parsing.
+			if !tt.wantErr {
+				typstCLI := typst.CLI{}
+				input := strings.NewReader("#" + result.String())
+				var output bytes.Buffer
+				if err := typstCLI.Render(input, &output, nil); err != nil {
+					t.Errorf("Compilation failed: %v", err)
+				}
+			}
 		})
 	}
 }