check unused and unmodified vars in all modules, not just main

examples/hello_world.v

@@ -1 +1,2 @@
 println('Hello, World!')
+

vlib/benchmark/benchmark.v

@@ -81,11 +81,11 @@ pub fn (b mut Benchmark) neither_fail_nor_ok() {
 	b.step_end_time = benchmark.now()
 }
 
-pub fn (b mut Benchmark) step_message(msg string) string {
+pub fn (b &Benchmark) step_message(msg string) string {
 	return b.tdiff_in_ms(msg, b.step_start_time, b.step_end_time)
 }
 
-pub fn (b mut Benchmark) total_message(msg string) string {
+pub fn (b &Benchmark) total_message(msg string) string {
 	mut tmsg := '$msg \n ok, fail, total = ' +
 		term.ok_message('${b.nok:5d}') + ', ' +
 		if b.nfail > 0 { term.fail_message('${b.nfail:5d}') } else { '${b.nfail:5d}' } + ', ' +
@@ -96,12 +96,12 @@ pub fn (b mut Benchmark) total_message(msg string) string {
 	return b.tdiff_in_ms(tmsg, b.bench_start_time, b.bench_end_time)
 }
 
-pub fn (b mut Benchmark) total_duration() i64 {
+pub fn (b &Benchmark) total_duration() i64 {
 	return (b.bench_end_time - b.bench_start_time)
 }
 ////////////////////////////////////////////////////////////////////
 
-fn (b mut Benchmark) tdiff_in_ms(s string, sticks i64, eticks i64) string {
+fn (b &Benchmark) tdiff_in_ms(s string, sticks i64, eticks i64) string {
 	if b.verbose {
 		tdiff := (eticks - sticks)
 		return '${tdiff:6lld} ms | $s'

vlib/compiler/cgen.v

@@ -43,7 +43,7 @@ mut:
 
 fn new_cgen(out_name_c string) &CGen {
 	path := out_name_c
-	mut out := os.create(path) or {
+	out := os.create(path) or {
 		println('failed to create $path')
 		return &CGen{}
 	}
@@ -192,7 +192,7 @@ fn (g mut CGen) register_thread_fn(wrapper_name, wrapper_text, struct_text strin
 }
 
 fn (v &V) prof_counters() string {
-	mut res := []string
+	res := []string
 	// Global fns
 	//for f in c.table.fns {
 		//res << 'double ${c.table.cgen_name(f)}_time;'
@@ -212,7 +212,7 @@ fn (v &V) prof_counters() string {
 }
 
 fn (p &Parser) print_prof_counters() string {
-	mut res := []string
+	res := []string
 	// Global fns
 	//for f in p.table.fns {
 		//counter := '${p.table.cgen_name(f)}_time'
@@ -410,10 +410,10 @@ fn (v &V) interface_table() string {
               sb.writeln('// NR methods = $t.gen_types.len')
                for i, gen_type in t.gen_types {
                        methods += '{'
-                       for i, method in t.methods {
+                       for j, method in t.methods {
 					       // Cat_speak
                                methods += '${gen_type}_${method.name}'
-                               if i < t.methods.len - 1 {
+                               if j < t.methods.len - 1 {
                                        methods += ', '
                                }
                        }

vlib/compiler/compile_errors.v

@@ -213,8 +213,8 @@ fn (s mut Scanner) goto_scanner_position(scp ScannerPos) {
 	s.last_nl_pos = scp.last_nl_pos
 }
 
-fn (s mut Scanner) get_last_nl_from_pos(_pos int) int {
+fn (s &Scanner) get_last_nl_from_pos(_pos int) int {
-	mut pos := if _pos >= s.text.len { s.text.len-1 } else { _pos }
+	pos := if _pos >= s.text.len { s.text.len-1 } else { _pos }
 	for i := pos; i >= 0; i-- {
 		if s.text[i] == `\n` {
 			return i
@@ -223,7 +223,7 @@ fn (s mut Scanner) get_last_nl_from_pos(_pos int) int {
 	return 0
 }
 
-fn (s mut Scanner) get_scanner_pos_of_token(tok &Token) ScannerPos {
+fn (s &Scanner) get_scanner_pos_of_token(tok &Token) ScannerPos {
 	return ScannerPos{
 		pos: tok.pos
 		line_nr: tok.line_nr

vlib/compiler/comptime.v

@@ -265,7 +265,7 @@ fn (p mut Parser) comptime_method_call(typ Type) {
 	p.check(.dollar)
 	var := p.check_name()
 	mut j := 0
-	for i, method in typ.methods {
+	for method in typ.methods {
 		if method.typ != 'void' {
 
 			continue

vlib/compiler/expression.v

@@ -392,7 +392,7 @@ fn (p mut Parser) expression() string {
 		//p.print_tok()
 	//}
 	ph := p.cgen.add_placeholder()
-	mut typ := p.indot_expr()
+	typ := p.indot_expr()
 	is_str := typ=='string'
 	is_ustr := typ=='ustring'
 	// `a << b` ==> `array_push(&a, b)`

vlib/compiler/fn.v

@@ -72,7 +72,7 @@ fn (a []TypeInst) str() string {
 	return r.str()
 }
 
-fn (p mut Parser) find_var_or_const(name string) ?Var {
+fn (p &Parser) find_var_or_const(name string) ?Var {
 	if p.known_var(name) {
 		return p.find_var(name)
 	}
@@ -150,14 +150,14 @@ fn (p mut Parser) mark_arg_moved(v Var) {
 	p.table.fns[p.cur_fn.name] = p.cur_fn
 }
 
-fn (p mut Parser) known_var(name string) bool {
+fn (p &Parser) known_var(name string) bool {
 	_ = p.find_var(name) or {
 		return false
 	}
 	return true
 }
 
-fn (p mut Parser) known_var_check_new_var(name string) bool {
+fn (p &Parser) known_var_check_new_var(name string) bool {
 	_ = p.find_var_check_new_var(name) or {
 		return false
 	}
@@ -561,15 +561,18 @@ fn (p mut Parser) fn_decl() {
 		// p.error('unclosed {')
 	}
 	// Make sure all vars in this function are used (only in main for now)
+	/*
 	if p.mod != 'main' {
 		p.genln('}')
 		return
 	}
+	*/
 	p.genln('}')
-	p.check_unused_variables()
+	if !p.builtin_mod && p.mod != 'os' {
+		p.check_unused_and_mut_vars()
+	}
 	p.set_current_fn(EmptyFn)
 	p.returns = false
-
 }
 
 [inline]
@@ -611,7 +614,7 @@ fn (p &Parser) get_linkage_prefix() string {
 	}
 }
 
-fn (p mut Parser) check_unused_variables() {
+fn (p mut Parser) check_unused_and_mut_vars() {
 	for var in p.local_vars {
 		if var.name == '' {
 			break
@@ -1365,7 +1368,7 @@ fn (p mut Parser) fn_call_vargs(f Fn) (string, []string) {
 		return '', []string
 	}
 	last_arg := f.args.last()
-	mut varg_def_type := last_arg.typ[3..]
+	//varg_def_type := last_arg.typ[3..]
 	mut types := []string
 	mut values := []string
 	for p.tok != .rpar {
@@ -1450,7 +1453,7 @@ fn (p mut Parser) dispatch_generic_fn_instance(f mut Fn, ti &TypeInst) {
 	}
 	if !new_inst {
 		rename_generic_fn_instance(mut f, ti)
-		_f := p.table.find_fn(f.name) or {
+		_ = p.table.find_fn(f.name) or {
 			p.error('function instance `$f.name` not found')
 			return
 		}

vlib/compiler/get_type.v

@@ -12,7 +12,7 @@ fn (p mut Parser) get_type2() Type{
 	mut mul := false
 	mut nr_muls := 0
 	mut typ := ''
-	mut cat := TypeCategory.struct_
+	cat := TypeCategory.struct_
 	// multiple returns
 	if p.tok == .lpar {
 		//p.warn('`()` are no longer necessary in multiple returns' +

vlib/compiler/main.v

@@ -133,7 +133,7 @@ pub mut:
 }
 
 // Should be called by main at the end of the compilation process, to cleanup
-pub fn (v mut V) finalize_compilation(){
+pub fn (v &V) finalize_compilation(){
 	// TODO remove
 	if v.pref.autofree {
 		/*
@@ -1184,7 +1184,7 @@ pub fn set_vroot_folder(vroot_path string) {
 	// Preparation for the compiler module:
 	// VEXE env variable is needed so that compiler.vexe_path()
 	// can return it later to whoever needs it:
-	mut vname := if os.user_os() == 'windows' { 'v.exe' } else { 'v' }
+	vname := if os.user_os() == 'windows' { 'v.exe' } else { 'v' }
 	os.setenv('VEXE', os.realpath( [vroot_path, vname].join(os.path_separator) ), true)
 }
 

vlib/compiler/module_header.v

@@ -45,7 +45,7 @@ fn generate_vh(mod string) {
 	out.writeln('module $mod_def\n')
 	// Consts
 	println(full_mod_path)
-	mut vfiles := os.walk_ext(full_mod_path, '.v')
+	vfiles := os.walk_ext(full_mod_path, '.v')
 	//mut vfiles := os.ls(full_mod_path) or {
 		//exit(1)
 	//}

vlib/compiler/parser.v

@@ -282,7 +282,7 @@ fn (p &Parser) log(s string) {
 */
 }
 
-pub fn (p mut Parser) save_state() ParserState {
+pub fn (p &Parser) save_state() ParserState {
 	return ParserState{
 		scanner_line_nr: p.scanner.line_nr
 		scanner_text   : p.scanner.text
@@ -1577,7 +1577,7 @@ fn (p mut Parser) var_decl() {
 				p.gen('$var_name = ${p.var_decl_name}.var_$i')
 				continue
 			}
-			// decleration
+			// declaration
 			p.gen('$var_type $var_name = ${p.var_decl_name}.var_$i')
 		}
 		p.register_var(Var {
@@ -1722,6 +1722,12 @@ fn (p mut Parser) var_expr(v Var) string {
 	// println('var expr is_tmp=$p.cgen.is_tmp\n')
 	if !v.is_const {
 		p.mark_var_used(v)
+		// `C.foo(&var)` means that `var` is changed. Mark it as changed
+		// to avoid `var was declared as mutable but was never changed` errors.
+		if p.calling_c && !v.is_changed {
+			//println('marking C var changed: $v.name')
+			p.mark_var_changed(v)
+		}
 	}
 	fn_ph := p.cgen.add_placeholder()
 	p.expr_var = v
@@ -1806,10 +1812,10 @@ fn (p mut Parser) dot(str_typ_ string, method_ph int) string {
 	//if p.fileis('orm_test') {
 		//println('ORM dot $str_typ')
 	//}
-	mut str_typ := str_typ_
+	str_typ := str_typ_
 	p.check(.dot)
 	is_variadic_arg := str_typ.starts_with('varg_')
-	mut typ := p.find_type(str_typ)
+	typ := p.find_type(str_typ)
 	if typ.name.len == 0 {
 		p.error('dot(): cannot find type `$str_typ`')
 	}
@@ -2513,7 +2519,6 @@ fn (p mut Parser) array_init() string {
 	mut typ := ''
 	new_arr_ph := p.cgen.add_placeholder()
 	mut i := 0
-	pos := p.cgen.cur_line.len// remember cur line to fetch first number in cgen       for [0; 10]
 	for p.tok != .rsbr {
 		val_typ := p.bool_expression()
 		// Get the type of the first expression
@@ -3095,7 +3100,7 @@ fn (p mut Parser) check_unused_imports() {
 	p.production_error_with_token_index( 'the following imports were never used: $output', 0 )
 }
 
-fn (p mut Parser) is_expr_fn_call(start_tok_idx int) (bool, string) {
+fn (p &Parser) is_expr_fn_call(start_tok_idx int) (bool, string) {
 	mut expr := p.tokens[start_tok_idx-1].str()
 	mut is_fn_call := p.tokens[start_tok_idx].tok == .lpar
 	if !is_fn_call {

vlib/compiler/vfmt.v

@@ -121,12 +121,12 @@ fn (p mut Parser) fnext() {
 	if p.tok == .rcbr && !p.inside_if_expr && p.prev_tok != .lcbr {
 		p.fmt_dec()
 	}
-	mut s := p.strtok()
+	s := p.strtok()
 	if p.tok != .eof {
 	p.fgen(s)
 	}
 	// vfmt: increase indentation on `{` unless it's `{}`
-	mut inc_indent := false
+	inc_indent := false
 	if p.tok == .lcbr && !p.inside_if_expr && p.peek() != .rcbr {
 		p.fgen_nl()
 		p.fmt_inc()
@@ -139,7 +139,7 @@ fn (p mut Parser) fnext() {
 			p.fgen_nl()
 			p.fgen_nl()
 		}
-		is_rcbr := p.tok == .rcbr
+		//is_rcbr := p.tok == .rcbr
 		for p.token_idx < p.tokens.len - 1 {
 			i := p.token_idx
 			tok := p.tokens[p.token_idx].tok

vlib/compiler/x64/gen.v

@@ -162,7 +162,7 @@ fn (g mut Gen) mov64(reg Register, val i64) {
 
 fn (g mut Gen) call(addr int) {
 	//rel := g.abs_to_rel_addr(addr)
-	rel := 0xffffffff - int(abs(addr - g.buf.len))-1
+	//rel := 0xffffffff - int(abs(addr - g.buf.len))-1
 
 	println('call addr=$addr rel_addr=$addr pos=$g.buf.len')
 	g.write8(0xe8)

vlib/crypto/aes/aes.v

@@ -11,7 +11,7 @@ import (
 	crypto.internal.subtle
 )
 
-const (
+pub const (
 	// The AES block size in bytes.
 	block_size = 16
 )

vlib/crypto/aes/aes_cbc.v

@@ -48,7 +48,7 @@ pub fn new_cbc(b AesCipher, iv []byte) AesCbc {
 
 pub fn (x &AesCbc) block_size() int { return x.block_size }
 
-pub fn (x mut AesCbc) encrypt_blocks(dst mut []byte, src_ []byte) {
+pub fn (x &AesCbc) encrypt_blocks(dst mut []byte, src_ []byte) {
 	mut src := src_
 	if src.len%x.block_size != 0 {
 		panic('crypto.cipher: input not full blocks')
@@ -124,7 +124,7 @@ pub fn (x mut AesCbc) decrypt_blocks(dst mut []byte, src []byte) {
 	x.tmp = x.iv
 }
 
-fn (x mut AesCbc) set_iv(iv []byte) {
+fn (x &AesCbc) set_iv(iv []byte) {
 	if iv.len != x.iv.len {
 		panic('cipher: incorrect length IV')
 	}

vlib/crypto/aes/aes_test.v

@@ -20,7 +20,7 @@ fn test_crypto_aes() {
 	if ciphertext.len%aes.block_size != 0 {
 		panic('ciphertext is not a multiple of the block size')
 	}
-	mut mode := aes.new_cbc(block, iv)
+	mode := aes.new_cbc(block, iv)
 	mode.encrypt_blocks(mut ciphertext, ciphertext)
 
 	assert ciphertext.hex() == 'c210459b514668ddc44674885e4979215265a6c44431a248421254ef357a8c2a308a8bddf5623af9df91737562041cf1'

vlib/crypto/md5/md5.v

@@ -14,7 +14,7 @@ module md5
 
 import encoding.binary
 
-const (
+pub const (
 	// The size of an MD5 checksum in bytes.
 	size = 16
 	// The blocksize of MD5 in bytes.

vlib/crypto/sha1/sha1.v

@@ -14,7 +14,7 @@ module sha1
 
 import encoding.binary
 
-const(
+pub const(
 	// The size of a SHA-1 checksum in bytes.
 	size     = 20
 	// The blocksize of SHA-1 in bytes.

vlib/crypto/sha256/sha256.v

@@ -12,7 +12,7 @@ module sha256
 
 import encoding.binary
 
-const (
+pub const (
 	// The size of a SHA256 checksum in bytes.
 	size = 32
 	// The size of a SHA224 checksum in bytes.
@@ -194,7 +194,7 @@ pub fn sum224(data []byte) []byte {
 	mut d := new224()
 	d.write(data)
 	sum := d.checksum()
-	mut sum224 := [byte(0)].repeat(size224)
+	sum224 := [byte(0)].repeat(size224)
 	copy(sum224, sum[..size224])
 	return sum224
 }

vlib/crypto/sha512/sha512.v

@@ -15,7 +15,7 @@ import (
 	encoding.binary
 )
 
-const (
+pub const (
 	// size is the size, in bytes, of a SHA-512 checksum.
 	size = 64
 	// size224 is the size, in bytes, of a SHA-512/224 checksum.
@@ -183,7 +183,7 @@ fn (d mut Digest) write(p_ []byte) int {
 	return nn
 }
 
-fn (d mut Digest) sum(b_in []byte) []byte {
+fn (d &Digest) sum(b_in []byte) []byte {
 	// Make a copy of d so that caller can keep writing and summing.
 	mut d0 := *d
 	hash := d0.checksum()
@@ -264,7 +264,7 @@ pub fn sum384(data []byte) []byte {
 	mut d := new_digest(.sha384)
 	d.write(data)
 	sum := d.checksum()
-	mut sum384 := [byte(0)].repeat(size384)
+	sum384 := [byte(0)].repeat(size384)
 	copy(sum384, sum[..size384])
 	return sum384
 }
@@ -274,7 +274,7 @@ pub fn sum512_224(data []byte) []byte {
 	mut d := new_digest(.sha512_224)
 	d.write(data)
 	sum := d.checksum()
-	mut sum224 := [byte(0)].repeat(size224)
+	sum224 := [byte(0)].repeat(size224)
 	copy(sum224, sum[..size224])
 	return sum224
 }
@@ -284,7 +284,7 @@ pub fn sum512_256(data []byte) []byte {
 	mut d := new_digest(.sha512_256)
 	d.write(data)
 	sum := d.checksum()
-	mut sum256 := [byte(0)].repeat(size256)
+	sum256 := [byte(0)].repeat(size256)
 	copy(sum256, sum[..size256])
 	return sum256
 }

vlib/freetype/freetype.v

@@ -140,8 +140,8 @@ pub fn new_context(cfg gg.Cfg) &FreeType {
 	if !cfg.use_ortho {
 		return &FreeType{}
 	}
-	mut width := cfg.width * scale
+	width := cfg.width * scale
-	mut height := cfg.height * scale
+	height := cfg.height * scale
 	font_size := cfg.font_size * scale
 	// exit('fs=$font_size')
 	// if false {
@@ -221,7 +221,7 @@ pub fn new_context(cfg gg.Cfg) &FreeType {
 	// # glVertexAttribPointer(0, 4, GL_FLOAT,false, 4 * sizeof(GLf32), 0);
 	// gl.bind_buffer(GL_ARRAY_BUFFER, uint(0))
 	// # glBindVertexArray(0);
-	mut ctx := &FreeType {
+	ctx := &FreeType {
 		shader: shader
 		width: width
 		height: height

vlib/gg/gg.v

@@ -275,8 +275,8 @@ fn todo_remove_me(cfg Cfg, scale int) {
 	if !cfg.use_ortho {
 		return
 	}
-	mut width := cfg.width * scale
+	width := cfg.width * scale
-	mut height := cfg.height * scale
+	height := cfg.height * scale
 	font_size := cfg.font_size * scale
 	gl.enable(C.GL_BLEND)
 	//# glBlendFunc(C.GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

vlib/gl/1shader.v

@@ -92,8 +92,8 @@ pub fn new_shader(name string) Shader {
 	if name.starts_with('/') {
 		dir = ''
 	}
-	vertex_path := '${dir}${name}.vert'
+	//vertex_path := '${dir}${name}.vert'
-	fragment_path := '${dir}${name}.frag'
+	//fragment_path := '${dir}${name}.frag'
 	//println('shader path=$vertex_path,\n fpath="$fragment_path"')
 	// vertex_src := os.read_file(vertex_path.trim_space())
 	mut vertex_src := ''

vlib/hash/crc32/crc32.v

@@ -58,6 +58,6 @@ pub fn new(poly int) &Crc32 {
 
 // calculate crc32 using ieee
 pub fn sum(b []byte) u32 {
-	mut c := new(ieee)
+	c := new(ieee)
 	return c.sum32(b)
 }

vlib/http/backend_nix.v

@@ -84,7 +84,7 @@ fn (req &Request) ssl_do(port int, method, host_name, path string) ?Response {
 	res = C.SSL_set_tlsext_host_name(ssl, host_name.str)
 	res = C.BIO_do_connect(web)
 	res = C.BIO_do_handshake(web)
-	cert := C.SSL_get_peer_certificate(ssl)
+	C.SSL_get_peer_certificate(ssl)
 	res = C.SSL_get_verify_result(ssl)
 	///////
 	s := req.build_request_headers(method, host_name, path)

vlib/http/http.v

@@ -137,8 +137,8 @@ pub fn (req &Request) do() ?Response {
 fn (req &Request) method_and_url_to_response(method string, url net_dot_urllib.URL) ?Response {
 	host_name := url.hostname()
 	scheme := url.scheme
-	mut p := url.path.trim_left('/')
+	p := url.path.trim_left('/')
-	mut path := if url.query().size > 0 { '/$p?${url.query().encode()}' } else { '/$p' }
+	path := if url.query().size > 0 { '/$p?${url.query().encode()}' } else { '/$p' }
 	mut nport := url.port().int()
 	if nport == 0 {
 		if scheme == 'http'  { nport = 80  }

vlib/log/log.v

@@ -80,7 +80,7 @@ pub fn (l mut Log) set_output_path(output_file_path string) {
 	if l.ofile.is_opened() { l.ofile.close() }
 	l.output_to_file = true
 	l.output_file_name = filepath.join( os.realpath( output_file_path ) , l.output_label )
-	mut ofile := os.open_append( l.output_file_name  ) or {
+	ofile := os.open_append( l.output_file_name  ) or {
 		panic('error while opening log file ${l.output_file_name} for appending')
 	}
 	l.ofile = ofile
@@ -96,7 +96,7 @@ fn (l mut Log) log_file(s string, level LogLevel) {
 	l.ofile.writeln('$timestamp [$e] $s')
 }
 
-fn (l mut Log) log_cli(s string, level LogLevel) {
+fn (l &Log) log_cli(s string, level LogLevel) {
 	f := tag(level)
 	t := time.now()
 	println('[$f ${t.format_ss()}] $s')

vlib/net/socket.v

@@ -134,10 +134,10 @@ pub fn listen(port int) ?Socket {
 	s := new_socket(C.AF_INET, C.SOCK_STREAM, 0) or {
 		return error(err)
 	}
-	bind_res := s.bind(port) or {
+	_ = s.bind(port) or {
 		return error(err)
 	}
-	listen_res := s.listen() or {
+	_ = s.listen() or {
 		return error(err)
 	}
 	return s
@@ -196,7 +196,7 @@ pub fn dial(address string, port int) ?Socket {
 	s := new_socket(C.AF_INET, C.SOCK_STREAM, 0) or {
 		return error(err)
 	}
-	res := s.connect(address, port) or {
+	_ = s.connect(address, port) or {
 		return error(err)
 	}
 	return s

vlib/net/urllib/urllib.v

@@ -260,7 +260,7 @@ fn escape(s string, mode EncodingMode) string {
 		return s
 	}
 
-	mut buf := [byte(0)].repeat(64)
+	buf := [byte(0)].repeat(64)
 	mut t := []byte
 
 	required := s.len + 2*hex_count
@@ -677,7 +677,7 @@ fn (u mut URL) set_path(p string) ?bool {
 // reading u.raw_path directly.
 fn (u &URL) escaped_path() string {
 	if u.raw_path != '' && valid_encoded_path(u.raw_path) {
-		p := unescape(u.raw_path, .encode_path)
+		unescape(u.raw_path, .encode_path) or { return '' }
 		return u.raw_path
 	}
 	if u.path == '*' {

vlib/vweb/tmpl/tmpl.v

@@ -15,7 +15,7 @@ const (
 
 pub fn compile_template(path string) string {
 	//lines := os.read_lines(path)
-	mut html := os.read_file(path) or {
+	html := os.read_file(path) or {
 		panic('html failed')
 	}
 	mut	header := ''
@@ -27,7 +27,7 @@ pub fn compile_template(path string) string {
 	}
 	lines := html.split_into_lines()
 	mut s := strings.new_builder(1000)
-	base := path.all_after('/').replace('.html', '')
+	//base := path.all_after('/').replace('.html', '')
 	s.writeln('
 mut sb := strings.new_builder(${lines.len * 30})
 header := \'$header\'

vlib/vweb/vweb.v

@@ -44,6 +44,7 @@ mut:
 }
 
 pub fn (ctx Context) html(html string) {
+	//println('$html HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n$ctx.headers\r\n\r\n$html')
 	ctx.conn.write('HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n$ctx.headers\r\n\r\n$html') or { panic(err) }
 }
 
@@ -64,10 +65,11 @@ pub fn (ctx Context) not_found(s string) {
 }
 
 pub fn (ctx mut Context) set_cookie(key, val string) { // TODO support directives, escape cookie value (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie)
+	//println('Set-Cookie $key=$val')
 	ctx.add_header('Set-Cookie', '$key=$val')
 }
 
-pub fn (ctx mut Context) get_cookie(key string) ?string { // TODO refactor
+pub fn (ctx &Context) get_cookie(key string) ?string { // TODO refactor
 	cookie_header := ctx.get_header('Cookie')
 	cookie := if cookie_header.contains(';') {
 		cookie_header.find_between('$key=', ';')
@@ -81,10 +83,13 @@ pub fn (ctx mut Context) get_cookie(key string) ?string { // TODO refactor
 }
 
 fn (ctx mut Context) add_header(key, val string) {
-	ctx.headers = ctx.headers + if ctx.headers == '' { '$key: val' } else { '\r\n$key: val' }
+	//println('add_header($key, $val)')
+	ctx.headers = ctx.headers +
+		if ctx.headers == '' { '$key: $val' } else { '\r\n$key: $val' }
+	//println(ctx.headers)
 }
 
-fn (ctx mut Context) get_header(key string) string {
+fn (ctx &Context) get_header(key string) string {
 	return ctx.headers.find_between('\r\n$key: ', '\r\n')
 }