Fix load to return empty default struct, and add an internal file loader

bench/get_test.go

@@ -20,9 +20,9 @@ func BenchmarkRetrieveSimpleValues(b *testing.B) {
 
 	// Parse once before benchmarking retrieval
 	reader := strings.NewReader(configData)
-	cfg, err := config.Load(reader)
-	if err != nil {
-		b.Fatalf("Failed to parse config: %v", err)
+	cfg := config.Load(reader)
+	if cfg.HasError() {
+		b.Fatalf("Failed to parse config: %v", cfg.GetError().Error())
 	}
 
 	b.ResetTimer()
@@ -75,9 +75,9 @@ func BenchmarkRetrieveNestedValues(b *testing.B) {
 
 	// Parse once before benchmarking retrieval
 	reader := strings.NewReader(configData)
-	cfg, err := config.Load(reader)
-	if err != nil {
-		b.Fatalf("Failed to parse config: %v", err)
+	cfg := config.Load(reader)
+	if cfg.HasError() {
+		b.Fatalf("Failed to parse config: %v", cfg.GetError().Error())
 	}
 
 	b.ResetTimer()
@@ -125,9 +125,9 @@ func BenchmarkRetrieveArrayValues(b *testing.B) {
 
 	// Parse once before benchmarking retrieval
 	reader := strings.NewReader(configData)
-	cfg, err := config.Load(reader)
-	if err != nil {
-		b.Fatalf("Failed to parse config: %v", err)
+	cfg := config.Load(reader)
+	if cfg.HasError() {
+		b.Fatalf("Failed to parse config: %v", cfg.GetError().Error())
 	}
 
 	b.ResetTimer()
@@ -180,9 +180,9 @@ func BenchmarkRetrieveMixedValues(b *testing.B) {
 
 	// Parse once before benchmarking retrieval
 	reader := strings.NewReader(configData)
-	cfg, err := config.Load(reader)
-	if err != nil {
-		b.Fatalf("Failed to parse config: %v", err)
+	cfg := config.Load(reader)
+	if cfg.HasError() {
+		b.Fatalf("Failed to parse config: %v", cfg.GetError().Error())
 	}
 
 	b.ResetTimer()
@@ -531,14 +531,14 @@ write = 10
 
 	// Custom config
 	customReader := strings.NewReader(customConfig)
-	customCfg, err := config.Load(customReader)
-	if err != nil {
-		b.Fatalf("Failed to parse custom config: %v", err)
+	customCfg := config.Load(customReader)
+	if customCfg.HasError() {
+		b.Fatalf("Failed to parse custom config: %v", customCfg.GetError().Error())
 	}
 
 	// JSON config
 	var jsonResult map[string]any
-	err = json.Unmarshal([]byte(jsonConfig), &jsonResult)
+	err := json.Unmarshal([]byte(jsonConfig), &jsonResult)
 	if err != nil {
 		b.Fatalf("Failed to parse JSON: %v", err)
 	}

bench/parse_test.go

@@ -23,9 +23,9 @@ func BenchmarkSmallConfig(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		reader := strings.NewReader(smallConfig)
-		_, err := config.Load(reader)
-		if err != nil {
-			b.Fatalf("Failed to parse small config: %v", err)
+		cfg := config.Load(reader)
+		if cfg.HasError() {
+			b.Fatalf("Failed to parse small config: %v", cfg.GetError().Error())
 		}
 	}
 }
@@ -74,9 +74,9 @@ func BenchmarkMediumConfig(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		reader := strings.NewReader(mediumConfig)
-		_, err := config.Load(reader)
-		if err != nil {
-			b.Fatalf("Failed to parse medium config: %v", err)
+		cfg := config.Load(reader)
+		if cfg.HasError() {
+			b.Fatalf("Failed to parse small config: %v", cfg.GetError().Error())
 		}
 	}
 }
@@ -170,9 +170,9 @@ func BenchmarkLargeConfig(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		reader := strings.NewReader(largeConfig)
-		_, err := config.Load(reader)
-		if err != nil {
-			b.Fatalf("Failed to parse large config: %v", err)
+		cfg := config.Load(reader)
+		if cfg.HasError() {
+			b.Fatalf("Failed to parse small config: %v", cfg.GetError().Error())
 		}
 	}
 }

data.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"maps"
+	"os"
 	"slices"
 	"strconv"
 )
@@ -15,6 +16,7 @@ type Data struct {
 	currentObject map[string]any
 	stack         []map[string]any
 	currentToken  Token
+	lastError     error
 }
 
 func NewData() *Data {
@@ -485,14 +487,36 @@ func (d *Data) parseObject() (any, error) {
 	}
 }
 
-func Load(r io.Reader) (*Data, error) {
+func Load(r io.Reader) *Data {
 	data := NewData()
 	err := data.Parse(r)
 	if err != nil {
 		data.Release()
-		return nil, err
+		emptyData := NewData()
+		emptyData.lastError = err
+		return emptyData
 	}
-	return data, nil
+	return data
+}
+
+func LoadFromFile(filepath string) *Data {
+	file, err := os.Open(filepath)
+	if err != nil {
+		emptyData := NewData()
+		emptyData.lastError = err
+		return emptyData
+	}
+	defer file.Close()
+
+	return Load(file)
+}
+
+func (d *Data) HasError() bool {
+	return d.lastError != nil
+}
+
+func (d *Data) GetError() error {
+	return d.lastError
 }
 
 func (d *Data) tokenToValue(token Token) any {

tests/read_test.go

@@ -18,9 +18,9 @@ func TestBasicKeyValuePairs(t *testing.T) {
 	negativeFloat -2.5
 	stringValue "hello world"
 	`
-	config, err := fin.Load(strings.NewReader(input))
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
+	config := fin.Load(strings.NewReader(input))
+	if config.HasError() {
+		t.Fatalf("unexpected error: %v", config.GetError().Error())
 	}
 
 	// Verify boolean values
@@ -98,9 +98,9 @@ func TestComments(t *testing.T) {
 	}
 	`
 
-	config, err := fin.Load(strings.NewReader(input))
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
+	config := fin.Load(strings.NewReader(input))
+	if config.HasError() {
+		t.Fatalf("unexpected error: %v", config.GetError().Error())
 	}
 
 	// Verify that comments are properly ignored and values are parsed
@@ -144,9 +144,9 @@ func TestArrays(t *testing.T) {
 	}
 	`
 
-	config, err := fin.Load(strings.NewReader(input))
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
+	config := fin.Load(strings.NewReader(input))
+	if config.HasError() {
+		t.Fatalf("unexpected error: %v", config.GetError().Error())
 	}
 
 	// Verify simple array
@@ -221,9 +221,9 @@ func TestMaps(t *testing.T) {
 	}
 	`
 
-	config, err := fin.Load(strings.NewReader(input))
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
+	config := fin.Load(strings.NewReader(input))
+	if config.HasError() {
+		t.Fatalf("unexpected error: %v", config.GetError().Error())
 	}
 
 	// Verify simple map

tests/write_test.go

@@ -28,9 +28,9 @@ func TestBasicWrite(t *testing.T) {
 	}
 
 	// Read back
-	readData, err := fin.Load(bytes.NewReader(buf.Bytes()))
-	if err != nil {
-		t.Fatalf("unexpected error loading written data: %v", err)
+	readData := fin.Load(bytes.NewReader(buf.Bytes()))
+	if readData.HasError() {
+		t.Fatalf("unexpected error loading written data: %v", readData.GetError().Error())
 	}
 
 	// Verify values
@@ -72,9 +72,9 @@ func TestArrayWrite(t *testing.T) {
 	}
 
 	// Read back
-	readData, err := fin.Load(bytes.NewReader(buf.Bytes()))
-	if err != nil {
-		t.Fatalf("unexpected error loading written data: %v", err)
+	readData := fin.Load(bytes.NewReader(buf.Bytes()))
+	if readData.HasError() {
+		t.Fatalf("unexpected error loading written data: %v", readData.GetError().Error())
 	}
 
 	// Verify arrays
@@ -149,9 +149,9 @@ func TestMapWrite(t *testing.T) {
 	}
 
 	// Read back
-	readData, err := fin.Load(bytes.NewReader(buf.Bytes()))
-	if err != nil {
-		t.Fatalf("unexpected error loading written data: %v", err)
+	readData := fin.Load(bytes.NewReader(buf.Bytes()))
+	if readData.HasError() {
+		t.Fatalf("unexpected error loading written data: %v", readData.GetError().Error())
 	}
 
 	// Verify simple map
@@ -198,9 +198,9 @@ func TestSpecialCasesWrite(t *testing.T) {
 	}
 
 	// Read back
-	readData, err := fin.Load(bytes.NewReader(buf.Bytes()))
-	if err != nil {
-		t.Fatalf("unexpected error loading written data: %v", err)
+	readData := fin.Load(bytes.NewReader(buf.Bytes()))
+	if readData.HasError() {
+		t.Fatalf("unexpected error loading written data: %v", readData.GetError().Error())
 	}
 
 	// Verify combined value+object
@@ -231,9 +231,9 @@ func TestStringEscapingWrite(t *testing.T) {
 	}
 
 	// Read back
-	readData, err := fin.Load(bytes.NewReader(buf.Bytes()))
-	if err != nil {
-		t.Fatalf("unexpected error loading written data: %v", err)
+	readData := fin.Load(bytes.NewReader(buf.Bytes()))
+	if readData.HasError() {
+		t.Fatalf("unexpected error loading written data: %v", readData.GetError().Error())
 	}
 
 	// Verify escaped strings