Add comprehensive test system for Go-to-Zig compiler

- Implement end-to-end test runner for compilation and behavior tests
- Add test cases for basic print functionality
- Refactor translator to use proper AST generation
- Remove redundant programs directory in favor of tests

Makefile

@@ -1,5 +1,15 @@
 run:
 	go run internal/main.go -o hello.zig programs/hello.go && zig run hello.zig
 
-test:
+test: test-unit test-integration
+
+test-unit:
 	go test ./internal/zig
+
+test-integration:
+	go run ./cmd/testrunner
+
+test-quick:
+	go run ./cmd/testrunner
+
+.PHONY: run test test-unit test-integration test-quick

cmd/testrunner/main.go

@@ -0,0 +1,228 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+type TestResult struct {
+	Name    string
+	Passed  bool
+	Output  string
+	Error   string
+	Elapsed time.Duration
+}
+
+type TestCase struct {
+	GoFile       string
+	ExpectedFile string
+	ErrorFile    string
+	StdinFile    string
+	ArgsFile     string
+}
+
+func main() {
+	// Find all test cases
+	testCases, err := findTestCases("tests")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error finding tests: %v\n", err)
+		os.Exit(1)
+	}
+
+	if len(testCases) == 0 {
+		fmt.Println("No tests found")
+		os.Exit(0)
+	}
+
+	fmt.Printf("Running %d tests...\n\n", len(testCases))
+
+	// Run tests in parallel
+	results := runTests(testCases)
+
+	// Print results
+	passed := 0
+	failed := 0
+	for _, result := range results {
+		if result.Passed {
+			fmt.Printf("✓ %s (%v)\n", result.Name, result.Elapsed)
+			passed++
+		} else {
+			fmt.Printf("✗ %s (%v)\n", result.Name, result.Elapsed)
+			fmt.Printf("  Error: %s\n", result.Error)
+			if result.Output != "" {
+				fmt.Printf("  Output:\n%s\n", indent(result.Output, "    "))
+			}
+			failed++
+		}
+	}
+
+	fmt.Printf("\n%d passed, %d failed\n", passed, failed)
+
+	if failed > 0 {
+		os.Exit(1)
+	}
+}
+
+func findTestCases(dir string) ([]TestCase, error) {
+	var testCases []TestCase
+
+	err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if strings.HasSuffix(path, ".go") {
+			base := strings.TrimSuffix(path, ".go")
+			testCase := TestCase{
+				GoFile:       path,
+				ExpectedFile: base + ".expected",
+				ErrorFile:    base + ".error",
+				StdinFile:    base + ".stdin",
+				ArgsFile:     base + ".args",
+			}
+
+			// Check if either .expected or .error exists
+			if fileExists(testCase.ExpectedFile) || fileExists(testCase.ErrorFile) {
+				testCases = append(testCases, testCase)
+			}
+		}
+
+		return nil
+	})
+
+	return testCases, err
+}
+
+func runTests(testCases []TestCase) []TestResult {
+	results := make([]TestResult, len(testCases))
+	var wg sync.WaitGroup
+
+	for i, tc := range testCases {
+		wg.Add(1)
+		go func(idx int, testCase TestCase) {
+			defer wg.Done()
+			results[idx] = runTest(testCase)
+		}(i, tc)
+	}
+
+	wg.Wait()
+	return results
+}
+
+func runTest(tc TestCase) TestResult {
+	start := time.Now()
+	testName := filepath.Base(strings.TrimSuffix(tc.GoFile, ".go"))
+	
+	result := TestResult{
+		Name:    testName,
+		Elapsed: time.Since(start),
+	}
+
+	// Create temporary directory for test outputs
+	tempDir, err := os.MkdirTemp("", "go-zig-test-*")
+	if err != nil {
+		result.Error = fmt.Sprintf("Failed to create temp dir: %v", err)
+		return result
+	}
+	defer os.RemoveAll(tempDir)
+
+	zigFile := filepath.Join(tempDir, testName+".zig")
+
+	// Compile Go to Zig
+	compileCmd := exec.Command("go", "run", "./internal/main.go", "-o", zigFile, tc.GoFile)
+	var compileOut bytes.Buffer
+	compileCmd.Stderr = &compileOut
+	compileCmd.Stdout = &compileOut
+
+	if err := compileCmd.Run(); err != nil {
+		// Check if this is an expected compilation error
+		if fileExists(tc.ErrorFile) {
+			expectedError, _ := os.ReadFile(tc.ErrorFile)
+			actualError := strings.TrimSpace(compileOut.String())
+			expectedErrorStr := strings.TrimSpace(string(expectedError))
+			
+			if actualError == expectedErrorStr {
+				result.Passed = true
+			} else {
+				result.Error = fmt.Sprintf("Expected error:\n%s\n\nActual error:\n%s", expectedErrorStr, actualError)
+			}
+		} else {
+			result.Error = fmt.Sprintf("Compilation failed: %v\nOutput: %s", err, compileOut.String())
+		}
+		result.Elapsed = time.Since(start)
+		return result
+	}
+
+	// If we expected a compilation error but didn't get one
+	if fileExists(tc.ErrorFile) {
+		result.Error = "Expected compilation to fail, but it succeeded"
+		result.Elapsed = time.Since(start)
+		return result
+	}
+
+	// Run the Zig program
+	runCmd := exec.Command("zig", "run", zigFile)
+	
+	// Set up stdin if provided
+	if fileExists(tc.StdinFile) {
+		stdinData, _ := os.ReadFile(tc.StdinFile)
+		runCmd.Stdin = bytes.NewReader(stdinData)
+	}
+
+	// Set up args if provided
+	if fileExists(tc.ArgsFile) {
+		argsData, _ := os.ReadFile(tc.ArgsFile)
+		args := strings.Fields(string(argsData))
+		runCmd.Args = append(runCmd.Args, args...)
+	}
+
+	// Capture both stdout and stderr (Zig's debug.print goes to stderr)
+	output, err := runCmd.CombinedOutput()
+	if err != nil {
+		result.Error = fmt.Sprintf("Execution failed: %v\nOutput: %s", err, string(output))
+		result.Output = string(output)
+		result.Elapsed = time.Since(start)
+		return result
+	}
+
+	// Compare output with expected
+	if fileExists(tc.ExpectedFile) {
+		expectedOutput, _ := os.ReadFile(tc.ExpectedFile)
+		actualOutput := string(output)
+		
+		if actualOutput == string(expectedOutput) {
+			result.Passed = true
+		} else {
+			result.Error = fmt.Sprintf("Output mismatch.\nExpected:\n%s\nActual:\n%s", 
+				string(expectedOutput), actualOutput)
+			result.Output = actualOutput
+		}
+	} else {
+		// No expected file, just check it runs without error
+		result.Passed = true
+	}
+
+	result.Elapsed = time.Since(start)
+	return result
+}
+
+func fileExists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+func indent(s string, prefix string) string {
+	lines := strings.Split(s, "\n")
+	for i, line := range lines {
+		if line != "" {
+			lines[i] = prefix + line
+		}
+	}
+	return strings.Join(lines, "\n")
+}

hello.zig

@@ -0,0 +1,5 @@
+const std = @import("std");
+
+pub fn main() void {
+    std.debug.print("Hello, world\n", .{});
+}

internal/main.go

@@ -8,6 +8,8 @@ import (
 	"go/token"
 	"os"
 	"strings"
+
+	"git.frop.prof/luke/go-zig-compiler/internal/zig"
 )
 
 var (
@@ -36,57 +38,122 @@ func main() {
 		panic(err)
 	}
 
-	output, err := generate(f)
+	zigRoot, err := translateToZig(f)
 	if err != nil {
 		panic(err)
 	}
+	
 	outputFile, err := os.Create(*outputFilepath)
 	if err != nil {
 		panic(err)
 	}
-	_, err = outputFile.WriteString(output)
+	defer outputFile.Close()
+	
+	err = zig.Write(outputFile, zigRoot)
 	if err != nil {
 		panic(err)
 	}
-	fmt.Printf("%v:\n", *outputFilepath)
-	fmt.Println("--------------------")
-	fmt.Println(output)
 }
 
-func generate(f *ast.File) (string, error) {
-	sb := new(strings.Builder)
-
-	def := f.Decls[0].(*ast.FuncDecl)
-
-	if def.Name.Name != "main" {
-		return "", fmt.Errorf("must have main")
+func translateToZig(f *ast.File) (*zig.Root, error) {
+	// Create the root AST node
+	root := &zig.Root{
+		ContainerMembers: []*zig.ContainerMember{},
 	}
 
-	sb.WriteString(`const std = @import("std");`)
-	sb.WriteString("\npub fn main() void {\n")
+	// Add the std import
+	root.ContainerMembers = append(root.ContainerMembers, &zig.ContainerMember{
+		Decl: zig.DeclareGlobalVar("std", 
+			zig.Call(zig.Id("@import"), zig.StringLit("std")),
+			zig.GlobalVarConst,
+		),
+	})
 
-	stmt := def.Body.List[0].(*ast.ExprStmt)
-	call := stmt.X.(*ast.CallExpr)
-	fn := call.Fun.(*ast.Ident)
-
-	if fn.Name == "print" {
-		sb.WriteString(fmt.Sprintf(`std.debug.print(`))
-
-		args := call.Args
-		for _, arg := range args {
-			if s, ok := arg.(*ast.BasicLit); ok {
-				sb.WriteString(fmt.Sprintf("%s", s.Value))
-			} else {
-				panic("WTF")
+	// Find and translate the main function
+	for _, decl := range f.Decls {
+		if fn, ok := decl.(*ast.FuncDecl); ok && fn.Name.Name == "main" {
+			mainFunc, err := translateMainFunction(fn)
+			if err != nil {
+				return nil, err
 			}
+			root.ContainerMembers = append(root.ContainerMembers, &zig.ContainerMember{
+				Decl: mainFunc,
+			})
 		}
-
-		sb.WriteString(", .{});\n")
-	} else {
-		return "", fmt.Errorf("expected printf")
 	}
 
-	sb.WriteString("}\n")
-
-	return sb.String(), nil
+	return root, nil
+}
+
+func translateMainFunction(fn *ast.FuncDecl) (*zig.FnDecl, error) {
+	// Create the main function
+	stmts := []zig.Stmt{}
+	
+	// Translate each statement in the function body
+	for _, stmt := range fn.Body.List {
+		zigStmt, err := translateStatement(stmt)
+		if err != nil {
+			return nil, err
+		}
+		if zigStmt != nil {
+			stmts = append(stmts, zigStmt)
+		}
+	}
+	
+	return zig.DeclareFn(
+		"main",
+		zig.Id("void"),
+		zig.NewBlock(stmts...),
+		nil,
+		zig.FnExport,
+	), nil
+}
+
+func translateStatement(stmt ast.Stmt) (zig.Stmt, error) {
+	switch s := stmt.(type) {
+	case *ast.ExprStmt:
+		// Handle expression statements (like function calls)
+		expr, err := translateExpression(s.X)
+		if err != nil {
+			return nil, err
+		}
+		return zig.NewExprStmt(expr), nil
+	default:
+		return nil, fmt.Errorf("unsupported statement type: %T", stmt)
+	}
+}
+
+func translateExpression(expr ast.Expr) (zig.Expr, error) {
+	switch e := expr.(type) {
+	case *ast.CallExpr:
+		// Handle function calls
+		if ident, ok := e.Fun.(*ast.Ident); ok && ident.Name == "print" {
+			// Translate print() to std.debug.print()
+			args := []zig.Expr{}
+			
+			// First argument is the format string
+			if len(e.Args) > 0 {
+				if lit, ok := e.Args[0].(*ast.BasicLit); ok && lit.Kind == token.STRING {
+					// Remove quotes and use the string value
+					args = append(args, zig.StringLit(strings.Trim(lit.Value, `"`)))
+				} else {
+					return nil, fmt.Errorf("print() requires a string literal argument")
+				}
+			}
+			
+			// Second argument is always .{} for now
+			args = append(args, zig.InitList())
+			
+			return zig.Call(
+				zig.FieldAccess(
+					zig.FieldAccess(zig.Id("std"), "debug"),
+					"print",
+				),
+				args...,
+			), nil
+		}
+		return nil, fmt.Errorf("unsupported function call: %v", e.Fun)
+	default:
+		return nil, fmt.Errorf("unsupported expression type: %T", expr)
+	}
 }

internal/zig/ast.go

@@ -2,9 +2,10 @@
 package zig
 
 // Root is the top-level node of a Zig source file.
+// It represents the entire compilation unit.
 type Root struct {
-	ContainerDocComment DocComment // //! Doc Comment (optional)
-	ContainerMembers    []*ContainerMember
+	ContainerDocComment DocComment         // Module-level doc comment using //!
+	ContainerMembers    []*ContainerMember // Top-level declarations and fields
 }
 
 type ContainerMember struct {
@@ -27,14 +28,21 @@ type Decl interface {
 	isDecl()
 }
 
+// FnFlags is a bitfield for function declaration options.
+type FnFlags uint8
+
+const (
+	FnExport FnFlags = 1 << iota
+	FnExtern
+	FnInline
+	FnNoInline
+	FnThreadLocal
+)
+
 // FnDecl represents a function declaration.
 type FnDecl struct {
-	Export      bool
-	Extern      bool
+	Flags       FnFlags
 	ExternName  string // Optional string for extern
-	Inline      bool
-	NoInline    bool
-	ThreadLocal bool
 	Name        string // May be empty (anonymous)
 	Params      []*ParamDecl
 	ByteAlign   *Expr
@@ -47,13 +55,22 @@ type FnDecl struct {
 
 func (*FnDecl) isDecl() {}
 
-// GlobalVarDecl represents a global variable declaration.
+// GlobalVarFlags is a bitfield for global variable declaration options.
+type GlobalVarFlags uint8
+
+const (
+	GlobalVarConst GlobalVarFlags = 1 << iota
+	GlobalVarExport
+	GlobalVarExtern
+	GlobalVarThreadLocal
+)
+
+// GlobalVarDecl represents a top-level (global) variable or constant declaration.
+// These are only allowed at the container/module scope and use a restricted syntax:
+// no destructuring or multi-var declarations, just a single name and optional type/initializer.
 type GlobalVarDecl struct {
-	Export      bool
-	Extern      bool
+	Flags       GlobalVarFlags
 	ExternName  string // Optional string for extern
-	ThreadLocal bool
-	Const       bool
 	Name        string
 	Type        TypeExpr // Optional
 	ByteAlign   *Expr
@@ -95,6 +112,35 @@ type ParamDecl struct {
 	Type       TypeExpr // 'anytype' if empty
 }
 
+// ContainerKind represents the kind of container (struct, enum, union, opaque).
+type ContainerKind int
+
+const (
+	ContainerStruct ContainerKind = iota
+	ContainerEnum
+	ContainerUnion
+	ContainerOpaque
+)
+
+// ContainerDecl represents a struct, enum, union, or opaque declaration.
+type ContainerDecl struct {
+	Extern     bool
+	Packed     bool
+	Kind       ContainerKind
+	TagType    TypeExpr // Optional (for enum/union)
+	Fields     []*ContainerMember
+	DocComment DocComment
+}
+
+func (*ContainerDecl) isDecl() {}
+
+// ErrorSetDecl represents an error set declaration.
+type ErrorSetDecl struct {
+	Names []string
+}
+
+func (*ErrorSetDecl) isDecl() {}
+
 // Block represents a block of statements.
 type Block struct {
 	Label string // Optional
@@ -113,7 +159,8 @@ type ExprStmt struct {
 
 func (*ExprStmt) isStmt() {}
 
-// VarDeclStmt represents a variable or const declaration at statement level, supporting destructuring and multi-var declarations.
+// VarDeclStmt represents a local variable or constant declaration statement inside a function or block.
+// These support destructuring and multi-var declarations, and are only valid at statement/block scope.
 type VarDeclStmt struct {
 	Const       bool
 	Pattern     VarPattern // Destructuring or multiple variable names
@@ -190,10 +237,18 @@ type ContinueStmt struct {
 
 func (*ContinueStmt) isStmt() {}
 
+// LoopKind represents the kind of loop (for or while).
+type LoopKind int
+
+const (
+	LoopFor LoopKind = iota
+	LoopWhile
+)
+
 // LoopStmt represents a for/while loop statement.
 type LoopStmt struct {
 	Inline  bool       // True if 'inline' is present
-	Kind    string     // "for" or "while"
+	Kind    LoopKind   // For or While
 	Prefix  LoopPrefix // ForPrefix or WhilePrefix
 	Body    Stmt       // Loop body
 	Else    Stmt       // Optional else branch
@@ -276,21 +331,6 @@ type AsmInputItem struct {
 	Expr       Expr
 }
 
-// ContainerDecl represents a struct, enum, union, or opaque declaration.
-type ContainerDecl struct {
-	Extern     bool
-	Packed     bool
-	Kind       string   // "struct", "enum", "union", "opaque"
-	TagType    TypeExpr // Optional (for enum/union)
-	Fields     []*ContainerMember
-	DocComment DocComment
-}
-
-// ErrorSetDecl represents an error set declaration.
-type ErrorSetDecl struct {
-	Names []string
-}
-
 // InitListExpr represents an initializer list.
 // Exactly one of Fields, Values, or Empty must be set (non-nil/non-empty or true).
 type InitListExpr struct {
@@ -310,9 +350,19 @@ type Identifier struct {
 	Name string // The identifier name
 }
 
+// LiteralKind represents the kind of literal.
+type LiteralKind int
+
+const (
+	LiteralInt LiteralKind = iota
+	LiteralFloat
+	LiteralString
+	LiteralChar
+)
+
 // Literal represents a literal value (int, float, string, char).
 type Literal struct {
-	Kind  string // "int", "float", "string", "char"
+	Kind  LiteralKind
 	Value string // The literal value as a string
 }
 
@@ -370,17 +420,39 @@ type NosuspendExpr struct {
 	Expr Expr // The expression to evaluate with nosuspend
 }
 
-// ContinueExpr represents a 'continue' expression.
-type ContinueExpr struct {
-	Label string // Optional label
-}
-
 // Expr is any expression.
+// This is an empty interface to allow maximum flexibility.
+// Consider using type switches when working with expressions.
 type Expr interface{}
 
 // TypeExpr is any type expression.
+// This is an empty interface to allow maximum flexibility.
+// Consider using type switches when working with type expressions.
 type TypeExpr interface{}
 
+// PrefixTypeExpr represents a type with a string prefix. Examples include optionals and pointers.
+type PrefixTypeExpr struct {
+	Op   string
+	Base TypeExpr
+}
+
+// ArrayTypeExpr represents an array type ([N]T).
+type ArrayTypeExpr struct {
+	Size Expr
+	Elem TypeExpr
+}
+
+// SliceTypeExpr represents a slice type ([]T).
+type SliceTypeExpr struct {
+	Elem TypeExpr
+}
+
+// ErrorUnionTypeExpr represents an error union type (E!T).
+type ErrorUnionTypeExpr struct {
+	ErrSet TypeExpr
+	Type   TypeExpr
+}
+
 // DocComment represents a doc comment (/// or //! lines).
 // Newlines in the string automatically add more comments in the output.
 type DocComment string
@@ -456,43 +528,14 @@ type AwaitExpr struct {
 // UnreachableExpr represents the 'unreachable' keyword.
 type UnreachableExpr struct{}
 
-// EmptyInitListExpr represents an empty initializer list '{}'.
-type EmptyInitListExpr struct{}
-
-// PositionalInitListExpr represents a positional initializer list '{expr, ...}'.
-type PositionalInitListExpr struct {
-	Values []Expr // Expressions in order
-}
-
-// FieldInitListExpr represents a field initializer list '{.field = expr, ...}'.
-type FieldInitListExpr struct {
-	Fields []*FieldInit // Field initializers
-}
-
-// SwitchProngPayload represents a switch prong payload (|*x, y|).
-type SwitchProngPayload struct {
-	Pointer bool
-	Names   []string
-}
-
-// SwitchProngCase represents a single case in a switch prong.
-type SwitchProngCase struct {
-	Expr Expr // The case expression
-	To   Expr // Optional, for ranges
-}
-
-// SwitchProngFull represents a full switch prong with cases and payload.
-type SwitchProngFull struct {
-	Inline  bool
-	Cases   []*SwitchProngCase  // One or more cases
-	Payload *SwitchProngPayload // Optional
-	Expr    Expr                // The result expression
-}
-
-// SwitchElseProng represents an 'else' prong in a switch.
-type SwitchElseProng struct {
-	Expr Expr // The result expression
-}
+// Note: The following types were removed as they were duplicates:
+// - EmptyInitListExpr (use InitListExpr with Empty=true)
+// - PositionalInitListExpr (use InitListExpr with Values)
+// - FieldInitListExpr (use InitListExpr with Fields)
+// - SwitchProngPayload (use Payload)
+// - SwitchProngCase (use SwitchCase)
+// - SwitchProngFull (use SwitchProng)
+// - SwitchElseProng (use SwitchProng with SwitchCase.IsElse=true)
 
 // VarPattern represents a variable pattern for destructuring or multiple variable declarations.
 type VarPattern struct {

internal/zig/asthelpers.go

@@ -0,0 +1,370 @@
+package zig
+
+// Id creates an identifier expression.
+func Id(name string) *Identifier {
+	return &Identifier{Name: name}
+}
+
+// IntLit creates an integer literal.
+func IntLit(value string) *Literal {
+	return &Literal{Kind: LiteralInt, Value: value}
+}
+
+// FloatLit creates a float literal.
+func FloatLit(value string) *Literal {
+	return &Literal{Kind: LiteralFloat, Value: value}
+}
+
+// StringLit creates a string literal.
+func StringLit(value string) *Literal {
+	return &Literal{Kind: LiteralString, Value: value}
+}
+
+// CharLit creates a character literal.
+func CharLit(value string) *Literal {
+	return &Literal{Kind: LiteralChar, Value: value}
+}
+
+// FieldAccess creates a field access expression.
+func FieldAccess(recv Expr, field string) *FieldAccessExpr {
+	return &FieldAccessExpr{Receiver: recv, Field: field}
+}
+
+// Call creates a function call expression.
+func Call(fun Expr, args ...Expr) *CallExpr {
+	return &CallExpr{Fun: fun, Args: args}
+}
+
+// InitList creates an initializer list expression.
+func InitList(exprs ...Expr) *InitListExpr {
+	if len(exprs) == 0 {
+		return &InitListExpr{Empty: true}
+	}
+	return &InitListExpr{Values: exprs}
+}
+
+// DeclareFn creates a function declaration with flags.
+func DeclareFn(name string, retType TypeExpr, body *Block, params []*ParamDecl, flags FnFlags) *FnDecl {
+	return &FnDecl{
+		Name:       name,
+		ReturnType: retType,
+		Body:       body,
+		Flags:      flags,
+		Params:     params,
+	}
+}
+
+// NewExprStmt creates an expression statement.
+func NewExprStmt(expr Expr) *ExprStmt {
+	return &ExprStmt{Expr: expr}
+}
+
+// DeclareVarStmt creates a variable or const declaration statement.
+func DeclareVarStmt(constant bool, names []string, typ TypeExpr, value Expr) *VarDeclStmt {
+	return &VarDeclStmt{
+		Const:   constant,
+		Pattern: VarPattern{Names: names},
+		Type:    typ,
+		Value:   value,
+	}
+}
+
+// DeclareGlobalVar creates a global variable declaration with flags.
+func DeclareGlobalVar(name string, value Expr, flags GlobalVarFlags) *GlobalVarDecl {
+	return &GlobalVarDecl{
+		Flags: flags,
+		Name:  name,
+		Value: value,
+	}
+}
+
+// Return creates a return statement.
+func Return(value Expr) *ReturnStmt {
+	return &ReturnStmt{Value: value}
+}
+
+// If creates an if statement.
+func If(cond Expr, then, els Stmt) *IfStmt {
+	return &IfStmt{Cond: cond, Then: then, Else: els}
+}
+
+// IfWithPayload creates an if statement with a payload.
+func IfWithPayload(cond Expr, payload *Payload, then, els Stmt) *IfStmt {
+	return &IfStmt{Cond: cond, Payload: payload, Then: then, Else: els}
+}
+
+// NewBlock creates a block of statements.
+func NewBlock(stmts ...Stmt) *Block {
+	return &Block{Stmts: stmts}
+}
+
+// NewBlock creates a block statement containing a block of statements.
+func NewBlockStmt(stmts ...Stmt) *BlockStmt {
+	return &BlockStmt{
+		Block: &Block{Stmts: stmts},
+	}
+}
+
+// Try creates a try expression.
+func Try(expr Expr) *TryExpr {
+	return &TryExpr{Expr: expr}
+}
+
+// Binary creates a binary expression.
+func Binary(op string, left, right Expr) *BinaryExpr {
+	return &BinaryExpr{Op: op, Left: left, Right: right}
+}
+
+// Param creates a function parameter declaration.
+func Param(name string, typ TypeExpr) *ParamDecl {
+	return &ParamDecl{Name: name, Type: typ}
+}
+
+// StructDecl creates a struct declaration with the given fields/members.
+func StructDecl(fields ...*ContainerMember) *ContainerDecl {
+	return &ContainerDecl{
+		Kind:   ContainerStruct,
+		Fields: fields,
+	}
+}
+
+// Field creates a struct field (optionally with initializer).
+func Field(name string, typ TypeExpr, byteAlign *Expr, value Expr) *ContainerMember {
+	return &ContainerMember{
+		Field: &ContainerField{
+			Name:      name,
+			Type:      typ,
+			ByteAlign: byteAlign,
+			Value:     value,
+		},
+	}
+}
+
+// Method creates a method (function declaration) as a struct member.
+func Method(fn *FnDecl) *ContainerMember {
+	return &ContainerMember{Decl: fn}
+}
+
+// OptionalType creates an optional type (?T).
+func OptionalType(base TypeExpr) *PrefixTypeExpr {
+	return &PrefixTypeExpr{Op: "?", Base: base}
+}
+
+// PointerType creates a pointer type (*T).
+func PointerType(base TypeExpr) *PrefixTypeExpr {
+	return &PrefixTypeExpr{Op: "*", Base: base}
+}
+
+// ArrayType creates an array type ([N]T).
+func ArrayType(size Expr, elem TypeExpr) *ArrayTypeExpr {
+	return &ArrayTypeExpr{Size: size, Elem: elem}
+}
+
+// ErrorSet creates an error set declaration.
+func ErrorSet(names ...string) *ErrorSetDecl {
+	return &ErrorSetDecl{Names: names}
+}
+
+// ErrorUnionType creates an error union type (E!T).
+func ErrorUnionType(errSet, typ TypeExpr) *ErrorUnionTypeExpr {
+	return &ErrorUnionTypeExpr{ErrSet: errSet, Type: typ}
+}
+
+// DeferStmt creates a defer statement.
+func Defer(stmt Stmt) *DeferStmt {
+	return &DeferStmt{Stmt: stmt}
+}
+
+// ForLoop creates a for loop statement.
+func ForLoop(args []ForArg, payload *Payload, body Stmt, els Stmt) *LoopStmt {
+	return &LoopStmt{
+		Kind:   LoopFor,
+		Prefix: &ForPrefix{Args: args, Payload: payload},
+		Body:   body,
+		Else:   els,
+	}
+}
+
+// WhileLoop creates a while loop statement.
+func WhileLoop(cond Expr, continueExpr Expr, payload *Payload, body Stmt, els Stmt) *LoopStmt {
+	return &LoopStmt{
+		Kind: LoopWhile,
+		Prefix: &WhilePrefix{
+			Cond:     cond,
+			Continue: continueExpr,
+			Payload:  payload,
+		},
+		Body: body,
+		Else: els,
+	}
+}
+
+// ForArg creates a for loop argument.
+func ForArgExpr(expr Expr) ForArg {
+	return ForArg{Expr: expr}
+}
+
+// Payload creates a payload for control flow.
+func PayloadNames(names []string, pointers []bool) *Payload {
+	return &Payload{Names: names, Pointers: pointers}
+}
+
+// SwitchStmt creates a switch statement.
+func Switch(cond Expr, prongs ...*SwitchProng) *SwitchStmt {
+	return &SwitchStmt{Cond: cond, Prongs: prongs}
+}
+
+// SwitchProng creates a switch prong.
+func Prong(cases []*SwitchCase, payload *Payload, expr Expr) *SwitchProng {
+	return &SwitchProng{Cases: cases, Payload: payload, Expr: expr}
+}
+
+// SwitchCase creates a switch case.
+func Case(expr Expr, to Expr) *SwitchCase {
+	return &SwitchCase{Expr: expr, To: to}
+}
+
+// ElseCase creates an else case for a switch.
+func ElseCase() *SwitchCase {
+	return &SwitchCase{IsElse: true}
+}
+
+// BreakStmt creates a break statement.
+func Break(label string, value Expr) *BreakStmt {
+	return &BreakStmt{Label: label, Value: value}
+}
+
+// ContinueStmt creates a continue statement.
+func Continue(label string) *ContinueStmt {
+	return &ContinueStmt{Label: label}
+}
+
+// UnaryExpr creates a unary expression.
+func Unary(op string, expr Expr) *UnaryExpr {
+	return &UnaryExpr{Op: op, Expr: expr}
+}
+
+// IndexExpr creates an index expression.
+func Index(receiver, index Expr) *IndexExpr {
+	return &IndexExpr{Receiver: receiver, Index: index}
+}
+
+// UnreachableExpr creates an unreachable expression.
+func Unreachable() *UnreachableExpr {
+	return &UnreachableExpr{}
+}
+
+// TestDecl creates a test declaration.
+func Test(name string, block *Block) *TestDecl {
+	return &TestDecl{Name: name, Block: block}
+}
+
+// GroupedExpr creates a grouped (parenthesized) expression.
+func Grouped(expr Expr) *GroupedExpr {
+	return &GroupedExpr{Expr: expr}
+}
+
+// ComptimeExpr creates a comptime expression.
+func Comptime(expr Expr) *ComptimeExpr {
+	return &ComptimeExpr{Expr: expr}
+}
+
+// NosuspendExpr creates a nosuspend expression.
+func Nosuspend(expr Expr) *NosuspendExpr {
+	return &NosuspendExpr{Expr: expr}
+}
+
+// SliceType creates a slice type ([]T).
+func SliceType(elem TypeExpr) *SliceTypeExpr {
+	return &SliceTypeExpr{Elem: elem}
+}
+
+// IfExpression creates an if expression.
+func IfExpression(cond Expr, then, els Expr) *IfExpr {
+	return &IfExpr{Cond: cond, Then: then, Else: els}
+}
+
+// IfExpressionWithPayload creates an if expression with a payload.
+func IfExpressionWithPayload(cond Expr, payload *Payload, then, els Expr) *IfExpr {
+	return &IfExpr{Cond: cond, Payload: payload, Then: then, Else: els}
+}
+
+// SwitchExpression creates a switch expression.
+func SwitchExpression(cond Expr, prongs ...*SwitchProng) *SwitchExpr {
+	return &SwitchExpr{Cond: cond, Prongs: prongs}
+}
+
+// EnumDecl creates an enum declaration.
+func EnumDecl(tagType TypeExpr, fields ...*ContainerMember) *ContainerDecl {
+	return &ContainerDecl{
+		Kind:    ContainerEnum,
+		TagType: tagType,
+		Fields:  fields,
+	}
+}
+
+// UnionDecl creates a union declaration.
+func UnionDecl(tagType TypeExpr, fields ...*ContainerMember) *ContainerDecl {
+	return &ContainerDecl{
+		Kind:    ContainerUnion,
+		TagType: tagType,
+		Fields:  fields,
+	}
+}
+
+// OpaqueDecl creates an opaque declaration.
+func OpaqueDecl() *ContainerDecl {
+	return &ContainerDecl{
+		Kind: ContainerOpaque,
+	}
+}
+
+// AsyncExpr creates an async expression.
+func Async(expr Expr) *AsyncExpr {
+	return &AsyncExpr{Expr: expr}
+}
+
+// AwaitExpr creates an await expression.
+func Await(expr Expr) *AwaitExpr {
+	return &AwaitExpr{Expr: expr}
+}
+
+// ResumeExpr creates a resume expression.
+func Resume(expr Expr) *ResumeExpr {
+	return &ResumeExpr{Expr: expr}
+}
+
+// DotAsterisk creates a .* expression (pointer dereference).
+func DotAsterisk(receiver Expr) *DotAsteriskExpr {
+	return &DotAsteriskExpr{Receiver: receiver}
+}
+
+// DotQuestion creates a .? expression (optional unwrap).
+func DotQuestion(receiver Expr) *DotQuestionExpr {
+	return &DotQuestionExpr{Receiver: receiver}
+}
+
+// ErrDefer creates an errdefer statement.
+func ErrDefer(payload *Payload, stmt Stmt) *DeferStmt {
+	return &DeferStmt{ErrDefer: true, Payload: payload, Stmt: stmt}
+}
+
+// UsingNamespace creates a usingnamespace declaration.
+func UsingNamespace(expr Expr) *UsingNamespaceDecl {
+	return &UsingNamespaceDecl{Expr: expr}
+}
+
+// ComptimeBlock creates a comptime block declaration.
+func ComptimeBlock(block *Block) *ComptimeDecl {
+	return &ComptimeDecl{Block: block}
+}
+
+// InitListFields creates an init list with field initializers.
+func InitListFields(fields ...*FieldInit) *InitListExpr {
+	return &InitListExpr{Fields: fields}
+}
+
+// FieldInitPair creates a field initializer.
+func FieldInitPair(name string, value Expr) *FieldInit {
+	return &FieldInit{Name: name, Value: value}
+}

internal/zig/zig.go

@@ -3,6 +3,7 @@ package zig
 import (
 	"fmt"
 	"io"
+	"strings"
 )
 
 type formatter struct {
@@ -15,9 +16,9 @@ type formatter struct {
 // indentStr defines the string used for each indentation level (4 spaces).
 const indentStr = "    "
 
-// Writef writes formatted text to the underlying writer and updates line/col counters.
+// writef writes formatted text to the underlying writer and updates line/col counters.
 // It also handles indentation after newlines when appropriate.
-func (f *formatter) Writef(format string, a ...any) {
+func (f *formatter) writef(format string, a ...any) {
 	s := fmt.Sprintf(format, a...)
 	for i, r := range s {
 		if r == '\n' {
@@ -62,37 +63,70 @@ func Write(w io.Writer, root *Root) (err error) {
 			}
 		}
 	}()
-	f := &formatter{w: w, line: 1, col: 1, indent: 0}
+	sb := &strings.Builder{}
+	f := &formatter{w: sb, line: 1, col: 1, indent: 0}
 
 	if root.ContainerDocComment != "" {
-		f.Writef("//! %s\n\n", root.ContainerDocComment)
+		f.writef("//! %s\n\n", root.ContainerDocComment)
 	}
-	for _, member := range root.ContainerMembers {
-		// Only handle Decl for now (fields not needed for hello world)
+	for i, member := range root.ContainerMembers {
 		if member.Decl != nil {
+			// Only emit a leading newline before a function/global after the first declaration
+			if i > 0 {
+				f.writef("\n")
+			}
 			writeDecl(f, member.Decl)
 		}
 	}
-	return nil
+	out := sb.String()
+	if len(out) == 0 || out[len(out)-1] != '\n' {
+		out += "\n"
+	}
+	_, err = w.Write([]byte(out))
+	return err
 }
 
 // writeDecl emits a top-level declaration.
 func writeDecl(f *formatter, decl Decl) {
 	switch d := decl.(type) {
 	case *FnDecl:
-		f.Writef("\nfn %s(", d.Name)
+		if d.Flags&FnExport != 0 {
+			f.writef("pub ")
+		}
+		f.writef("fn %s(", d.Name)
 		writeParams(f, d.Params)
-		f.Writef(") ")
+		f.writef(") ")
 		writeTypeExpr(f, d.ReturnType)
 		writeBlock(f, d.Body)
+		f.writef("\n")
 	case *GlobalVarDecl:
-		if d.Const {
-			f.Writef("const %s = ", d.Name)
+		if d.Flags&GlobalVarConst != 0 {
+			f.writef("const %s = ", d.Name)
 		} else {
-			f.Writef("var %s = ", d.Name)
+			f.writef("var %s = ", d.Name)
 		}
 		writeExpr(f, d.Value)
-		f.Writef(";\n")
+		f.writef(";\n")
+	case *ContainerDecl:
+		f.writef("struct ")
+		writeStructBody(f, d)
+	case *ErrorSetDecl:
+		writeExpr(f, d)
+	case *TestDecl:
+		f.writef("test ")
+		if d.Name != "" {
+			f.writef(`"%s"`, d.Name)
+		}
+		writeBlock(f, d.Block)
+		f.writef("\n")
+	case *UsingNamespaceDecl:
+		f.writef("usingnamespace ")
+		writeExpr(f, d.Expr)
+		f.writef(";\n")
+	case *ComptimeDecl:
+		f.writef("comptime")
+		writeBlock(f, d.Block)
+		f.writef("\n")
 	}
 }
 
@@ -100,10 +134,10 @@ func writeDecl(f *formatter, decl Decl) {
 func writeParams(f *formatter, params []*ParamDecl) {
 	for i, param := range params {
 		if i > 0 {
-			f.Writef(", ")
+			f.writef(", ")
 		}
 		if param.Name != "" {
-			f.Writef("%s: ", param.Name)
+			f.writef("%s: ", param.Name)
 		}
 		writeTypeExpr(f, param.Type)
 	}
@@ -113,48 +147,332 @@ func writeParams(f *formatter, params []*ParamDecl) {
 func writeTypeExpr(f *formatter, typ TypeExpr) {
 	switch t := typ.(type) {
 	case *Identifier:
-		f.Writef("%s", t.Name)
+		f.writef("%s", t.Name)
+	case *PrefixTypeExpr:
+		f.writef("%s", t.Op)
+		// Add space after multi-character operators like *const
+		if len(t.Op) > 1 && !strings.HasSuffix(t.Op, "]") {
+			f.writef(" ")
+		}
+		writeTypeExpr(f, t.Base)
+	case *ArrayTypeExpr:
+		f.writef("[")
+		writeExpr(f, t.Size)
+		f.writef("]")
+		writeTypeExpr(f, t.Elem)
+	case *SliceTypeExpr:
+		f.writef("[]")
+		writeTypeExpr(f, t.Elem)
+	case *ErrorUnionTypeExpr:
+		writeTypeExpr(f, t.ErrSet)
+		f.writef("!")
+		writeTypeExpr(f, t.Type)
 	case nil:
 		// nothing
 	default:
-		f.Writef("%v", t)
+		f.writef("%v", t)
 	}
 }
 
 // writeBlock emits a block, handling indentation for statements and the closing brace.
 func writeBlock(f *formatter, block *Block) {
 	if block == nil {
-		f.Writef(";")
+		f.writef(";")
 		return
 	}
-	f.Writef(" {\n")
-	f.indent++ // Increase indentation for block contents.
-	for i, stmt := range block.Stmts {
-		f.writeIndent() // Indent each statement.
+	f.writef(" {\n")
+	f.indent++
+	for _, stmt := range block.Stmts {
+		f.writeIndent()
 		writeStmt(f, stmt)
-		if i < len(block.Stmts)-1 {
-			f.Writef("\n")
-		}
+		f.writef("\n")
 	}
-	f.indent-- // Decrease indentation before closing brace.
-	f.Writef("\n")
-	f.writeIndent() // Indent the closing brace.
-	f.Writef("}\n")
+	f.indent--
+	f.writeIndent()
+	f.writef("}")
 }
 
 // writeStmt emits a statement. Indentation is handled by the caller (writeBlock).
 func writeStmt(f *formatter, stmt Stmt) {
 	switch s := stmt.(type) {
 	case *ReturnStmt:
-		f.Writef("return")
+		f.writef("return")
 		if s.Value != nil {
-			f.Writef(" ")
+			f.writef(" ")
 			writeExpr(f, s.Value)
 		}
-		f.Writef(";")
+		f.writef(";")
 	case *ExprStmt:
 		writeExpr(f, s.Expr)
-		f.Writef(";")
+		f.writef(";")
+	case *VarDeclStmt:
+		if s.Const {
+			f.writef("const ")
+		} else {
+			f.writef("var ")
+		}
+		for i, name := range s.Pattern.Names {
+			if i > 0 {
+				f.writef(", ")
+			}
+			f.writef("%s", name)
+		}
+		if s.Type != nil {
+			f.writef(": ")
+			writeTypeExpr(f, s.Type)
+		}
+		if s.Value != nil {
+			f.writef(" = ")
+			writeExpr(f, s.Value)
+		}
+		f.writef(";")
+	case *BlockStmt:
+		// Check if this is a labeled block
+		if s.Block != nil && s.Block.Label != "" {
+			f.writef("%s:", s.Block.Label)
+		}
+		// For standalone blocks, we need to write the block without a leading space
+		if s.Block == nil {
+			f.writef(";")
+		} else {
+			f.writef("{\n")
+			f.indent++
+			for _, stmt := range s.Block.Stmts {
+				f.writeIndent()
+				writeStmt(f, stmt)
+				f.writef("\n")
+			}
+			f.indent--
+			f.writeIndent()
+			f.writef("}")
+		}
+	case *IfStmt:
+		f.writef("if (")
+		writeExpr(f, s.Cond)
+		f.writef(")")
+
+		// Handle payload if present
+		if s.Payload != nil {
+			f.writef(" ")
+			writePayload(f, s.Payload)
+		}
+
+		// Always write the then branch as a block
+		if block, ok := s.Then.(*BlockStmt); ok {
+			writeBlock(f, block.Block)
+		} else {
+			f.writef(" ")
+			writeStmt(f, s.Then)
+		}
+		if s.Else != nil {
+			f.writef(" else")
+			if block, ok := s.Else.(*BlockStmt); ok {
+				writeBlock(f, block.Block)
+			} else {
+				f.writef(" ")
+				writeStmt(f, s.Else)
+			}
+		}
+	case *LoopStmt:
+		// Handle label if the body is a labeled block
+		if block, ok := s.Body.(*BlockStmt); ok && block.Block != nil && block.Block.Label != "" {
+			f.writef("%s: ", block.Block.Label)
+		}
+		
+		if s.Kind == LoopWhile {
+			f.writef("while (")
+			if wp, ok := s.Prefix.(*WhilePrefix); ok {
+				writeExpr(f, wp.Cond)
+				if wp.Continue != nil {
+					f.writef(") : (")
+					writeExpr(f, wp.Continue)
+				}
+			}
+			f.writef(")")
+			// Always write the body as a block
+			if block, ok := s.Body.(*BlockStmt); ok {
+				// Don't write the label again, just the block content
+				origLabel := ""
+				if block.Block != nil {
+					origLabel = block.Block.Label
+					block.Block.Label = "" // Temporarily clear to avoid double printing
+				}
+				writeBlock(f, block.Block)
+				if block.Block != nil {
+					block.Block.Label = origLabel // Restore
+				}
+			} else {
+				f.writef(" ")
+				writeStmt(f, s.Body)
+			}
+		} else if s.Kind == LoopFor {
+			f.writef("for (")
+			if fp, ok := s.Prefix.(*ForPrefix); ok {
+				for i, arg := range fp.Args {
+					if i > 0 {
+						f.writef(", ")
+					}
+					writeExpr(f, arg.Expr)
+					if arg.From != nil {
+						if lit, ok := arg.From.(*Literal); ok && lit.Value == "" {
+							f.writef("..")
+						} else {
+							f.writef("...")
+							writeExpr(f, arg.From)
+						}
+					}
+				}
+				f.writef(")")
+				if fp.Payload != nil {
+					f.writef(" ")
+					writePayload(f, fp.Payload)
+				}
+			}
+			// Always write the body as a block
+			if block, ok := s.Body.(*BlockStmt); ok {
+				// Don't write the label again, just the block content
+				origLabel := ""
+				if block.Block != nil {
+					origLabel = block.Block.Label
+					block.Block.Label = "" // Temporarily clear to avoid double printing
+				}
+				writeBlock(f, block.Block)
+				if block.Block != nil {
+					block.Block.Label = origLabel // Restore
+				}
+			} else {
+				f.writef(" ")
+				writeStmt(f, s.Body)
+			}
+		}
+	case *DeferStmt:
+		if s.ErrDefer {
+			f.writef("errdefer")
+			if s.Payload != nil {
+				f.writef(" ")
+				writePayload(f, s.Payload)
+			}
+		} else {
+			f.writef("defer")
+		}
+		f.writef(" ")
+		writeStmt(f, s.Stmt)
+	case *BreakStmt:
+		f.writef("break")
+		if s.Label != "" {
+			f.writef(" :%s", s.Label)
+		}
+		if s.Value != nil {
+			f.writef(" ")
+			writeExpr(f, s.Value)
+		}
+		f.writef(";")
+	case *ContinueStmt:
+		f.writef("continue")
+		if s.Label != "" {
+			f.writef(" :%s", s.Label)
+		}
+		f.writef(";")
+	case *SwitchStmt:
+		f.writef("switch (")
+		writeExpr(f, s.Cond)
+		f.writef(") {\n")
+		f.indent++
+		for _, prong := range s.Prongs {
+			f.writeIndent()
+			writeSwitchProng(f, prong)
+			f.writef("\n")
+		}
+		f.indent--
+		f.writeIndent()
+		f.writef("}")
+	}
+}
+
+// writePayload emits a payload (|x|, |*x|, |*x, y|, etc).
+func writePayload(f *formatter, payload *Payload) {
+	f.writef("|")
+	for i, name := range payload.Names {
+		if i > 0 {
+			f.writef(", ")
+		}
+		if payload.Pointers[i] {
+			f.writef("*")
+		}
+		f.writef("%s", name)
+	}
+	f.writef("|")
+}
+
+// writeSwitchProng emits a switch prong.
+func writeSwitchProng(f *formatter, prong *SwitchProng) {
+	for i, c := range prong.Cases {
+		if i > 0 {
+			f.writef(", ")
+		}
+		if c.IsElse {
+			f.writef("else")
+		} else {
+			writeExpr(f, c.Expr)
+			if c.To != nil {
+				f.writef("...")
+				writeExpr(f, c.To)
+			}
+		}
+	}
+	f.writef(" => ")
+	// Write payload if present after =>
+	if prong.Payload != nil {
+		writePayload(f, prong.Payload)
+		f.writef(" ")
+	}
+	// Check if the expression is actually a statement (like return or break)
+	if stmt, ok := prong.Expr.(Stmt); ok {
+		// If it's a block, write it directly without the leading space
+		if blockStmt, isBlock := stmt.(*BlockStmt); isBlock {
+			f.writef("{\n")
+			f.indent++
+			for _, s := range blockStmt.Block.Stmts {
+				f.writeIndent()
+				writeStmt(f, s)
+				f.writef("\n")
+			}
+			f.indent--
+			f.writeIndent()
+			f.writef("},")
+		} else {
+			// For single statements, write without the semicolon
+			switch s := stmt.(type) {
+			case *ReturnStmt:
+				f.writef("return")
+				if s.Value != nil {
+					f.writef(" ")
+					writeExpr(f, s.Value)
+				}
+			case *BreakStmt:
+				f.writef("break")
+				if s.Label != "" {
+					f.writef(" :%s", s.Label)
+				}
+				if s.Value != nil {
+					f.writef(" ")
+					writeExpr(f, s.Value)
+				}
+			case *ContinueStmt:
+				f.writef("continue")
+				if s.Label != "" {
+					f.writef(" :%s", s.Label)
+				}
+			case *ExprStmt:
+				writeExpr(f, s.Expr)
+			default:
+				writeStmt(f, stmt)
+			}
+			f.writef(",")
+		}
+	} else {
+		writeExpr(f, prong.Expr)
+		f.writef(",")
 	}
 }
 
@@ -162,34 +480,215 @@ func writeStmt(f *formatter, stmt Stmt) {
 func writeExpr(f *formatter, expr Expr) {
 	switch e := expr.(type) {
 	case *Identifier:
-		f.Writef("%s", e.Name)
+		f.writef("%s", e.Name)
 	case *CallExpr:
 		writeExpr(f, e.Fun)
-		f.Writef("(")
+		f.writef("(")
 		for i, arg := range e.Args {
 			if i > 0 {
-				f.Writef(", ")
+				f.writef(", ")
 			}
 			writeExpr(f, arg)
 		}
-		f.Writef(")")
+		f.writef(")")
 	case *FieldAccessExpr:
-		writeExpr(f, e.Receiver)
-		f.Writef(".%s", e.Field)
+		// Handle enum field access like .value (no receiver)
+		if id, ok := e.Receiver.(*Identifier); ok && id.Name == "" {
+			f.writef(".%s", e.Field)
+		} else {
+			writeExpr(f, e.Receiver)
+			f.writef(".%s", e.Field)
+		}
 	case *Literal:
 		switch e.Kind {
-		case "string":
-			f.Writef("%q", e.Value)
+		case LiteralString:
+			f.writef(`"%v"`, e.Value)
 		default:
-			f.Writef("%v", e.Value)
+			f.writef("%v", e.Value)
 		}
 	case *InitListExpr:
 		if e.Empty {
-			f.Writef(".{}")
-		} else {
-			f.Writef(".{")
-			// TODO
-			f.Writef("}")
+			f.writef(".{}")
+		} else if len(e.Values) > 0 {
+			if len(e.Values) == 1 {
+				f.writef(".{")
+				writeExpr(f, e.Values[0])
+				f.writef("}")
+			} else {
+				f.writef(".{ ")
+				for i, v := range e.Values {
+					if i > 0 {
+						f.writef(", ")
+					}
+					writeExpr(f, v)
+				}
+				f.writef(" }")
+			}
+		} else if len(e.Fields) > 0 {
+			f.writef(".{ ")
+			for i, field := range e.Fields {
+				if i > 0 {
+					f.writef(", ")
+				}
+				f.writef(".%s = ", field.Name)
+				writeExpr(f, field.Value)
+			}
+			f.writef(" }")
 		}
+	case *ContainerDecl:
+		switch e.Kind {
+		case ContainerStruct:
+			f.writef("struct ")
+			writeStructBody(f, e)
+		case ContainerEnum:
+			f.writef("enum ")
+			writeStructBody(f, e)
+		case ContainerUnion:
+			f.writef("union")
+			if e.TagType != nil {
+				f.writef("(")
+				writeTypeExpr(f, e.TagType)
+				f.writef(") ")
+			} else {
+				f.writef(" ")
+			}
+			writeStructBody(f, e)
+		case ContainerOpaque:
+			f.writef("opaque ")
+			writeStructBody(f, e)
+		default:
+			panic("unknown container kind")
+		}
+	case *TryExpr:
+		f.writef("try ")
+		writeExpr(f, e.Expr)
+	case *BinaryExpr:
+		writeExpr(f, e.Left)
+		f.writef(" %s ", e.Op)
+		// Special handling for orelse with block
+		if e.Op == "orelse" {
+			if _, ok := e.Right.(*BlockStmt); ok {
+				// For orelse blocks, we need special formatting
+				writeStmt(f, e.Right.(Stmt))
+			} else {
+				writeExpr(f, e.Right)
+			}
+		} else {
+			writeExpr(f, e.Right)
+		}
+	case *UnaryExpr:
+		f.writef("%s", e.Op)
+		writeExpr(f, e.Expr)
+	case *IndexExpr:
+		writeExpr(f, e.Receiver)
+		f.writef("[")
+		writeExpr(f, e.Index)
+		f.writef("]")
+	case *UnreachableExpr:
+		f.writef("unreachable")
+	case *ErrorSetDecl:
+		f.writef("error{\n")
+		f.indent++
+		for _, name := range e.Names {
+			f.writeIndent()
+			f.writef("%s,\n", name)
+		}
+		f.indent--
+		f.writeIndent()
+		f.writef("}")
+	case *GroupedExpr:
+		f.writef("(")
+		writeExpr(f, e.Expr)
+		f.writef(")")
+	case *ComptimeExpr:
+		f.writef("comptime ")
+		writeExpr(f, e.Expr)
+	case *NosuspendExpr:
+		f.writef("nosuspend ")
+		writeExpr(f, e.Expr)
+	case *AsyncExpr:
+		f.writef("async ")
+		writeExpr(f, e.Expr)
+	case *AwaitExpr:
+		f.writef("await ")
+		writeExpr(f, e.Expr)
+	case *ResumeExpr:
+		f.writef("resume ")
+		writeExpr(f, e.Expr)
+	case *DotAsteriskExpr:
+		writeExpr(f, e.Receiver)
+		f.writef(".*")
+	case *DotQuestionExpr:
+		writeExpr(f, e.Receiver)
+		f.writef(".?")
+	case *IfExpr:
+		f.writef("if (")
+		writeExpr(f, e.Cond)
+		f.writef(")")
+		if e.Payload != nil {
+			f.writef(" ")
+			writePayload(f, e.Payload)
+		}
+		f.writef(" ")
+		writeExpr(f, e.Then)
+		if e.Else != nil {
+			f.writef(" else ")
+			writeExpr(f, e.Else)
+		}
+	case *SwitchExpr:
+		f.writef("switch (")
+		writeExpr(f, e.Cond)
+		f.writef(") {\n")
+		f.indent++
+		for _, prong := range e.Prongs {
+			f.writeIndent()
+			writeSwitchProng(f, prong)
+			f.writef("\n")
+		}
+		f.indent--
+		f.writeIndent()
+		f.writef("}")
+	case *LabeledBlock:
+		f.writef("%s:", e.Label)
+		writeBlock(f, e.Block)
 	}
 }
+
+// writeStructBody emits the body of a struct/union/enum/opaque declaration.
+func writeStructBody(f *formatter, decl *ContainerDecl) {
+	f.writef("{\n")
+	f.indent++
+	for _, member := range decl.Fields {
+		if member.Field != nil {
+			// Field or const
+			if member.Field.Type == nil && member.Field.Value != nil {
+				// const field
+				f.writeIndent()
+				f.writef("const %s = ", member.Field.Name)
+				writeExpr(f, member.Field.Value)
+				f.writef(";\n")
+			} else {
+				// regular field
+				f.writeIndent()
+				f.writef("%s", member.Field.Name)
+				if member.Field.Type != nil {
+					f.writef(": ")
+					writeTypeExpr(f, member.Field.Type)
+				}
+				if member.Field.Value != nil {
+					f.writef(" = ")
+					writeExpr(f, member.Field.Value)
+				}
+				f.writef(",\n")
+			}
+		} else if member.Decl != nil {
+			// Method or nested decl
+			f.writef("\n")
+			f.writeIndent()
+			writeDecl(f, member.Decl)
+		}
+	}
+	f.indent--
+	f.writeIndent()
+	f.writef("}")
+}

tests/basic/hello.expected

@@ -0,0 +1 @@
+Hello, world!

tests/basic/hello.go

@@ -1,5 +1,5 @@
 package main
 
 func main() {
-	print("Hello, world\n")
-}
+	print("Hello, world!\n")
+}

tests/basic/multiple_prints.expected

@@ -0,0 +1 @@
+First Second

tests/basic/multiple_prints.go

@@ -0,0 +1,8 @@
+package main
+
+func main() {
+	print("First")
+	print(" ")
+	print("Second")
+	print("\n")
+}

tests/basic/print_escape.expected

@@ -0,0 +1,5 @@
+Hello	World!
+Line 1
+Line 2
+Quote: "test"
+Backslash: \

tests/basic/print_escape.go

@@ -0,0 +1,8 @@
+package main
+
+func main() {
+	print("Hello\tWorld!\n")
+	print("Line 1\nLine 2\n")
+	print("Quote: \"test\"\n")
+	print("Backslash: \\\n")
+}