add ArrayList alias to std

LANGUAGE.md

@@ -13,6 +13,8 @@ roadmap and milestone history.
 - package-level functions, globals, native type declarations, and `Name :: alias T`
 - directory packages with merged declarations
 - file-local relative imports, import aliases, and qualified member access
+- transparent declaration aliases with `Name :: alias package.Member`; functions/type factories,
+  named types, and globals retain their original declaration or storage identity
 - native top-level declarations beginning with `_` are visible only within their source file; locals, fields, parameters, and C declarations are unaffected
 - relative `.h` imports as synthetic C header package namespaces
 - root `main` validation with trap executable recovery for missing or unusable entry points
@@ -121,6 +123,7 @@ The six spellings are reserved only as direct unqualified calls. A qualified cal
 
 ### standard packages
 
+- root `std` re-exports `ArrayList(T)` while its operations remain in `std/arraylist`
 - `std/mem` generic slice equality, allocator contract with raw byte operations, typed `empty` / `alloc` / `realloc` / `free`, overflow checks, zero-sized-type support, and failure-preserving reallocation
 - `std/arraylist` generic `ArrayList(T)` with direct `items` slice access, explicit capacity, allocator ownership, fallible reserve/append, clear, and deinit
 - `std/io` explicit `Io` capabilities, `Reader`/`Writer` stream values, one-shot `read`/`write`, and allocation-free `write_all`

TODO.md

@@ -814,7 +814,14 @@
   - `read` and `write` validate provider counts; `write_all` handles partial writes and no progress
   - the system provider uses unbuffered libc `read`/`write`, retries interruption, and allocates nothing
 
-34. re-exports so `std` can re-export e.g. `ArrayList(T)`, so users can do `std.ArrayList(i32)` instead of `std.arraylist.ArrayList(i32)`, while still using `std.arraylist.append(&values, 420)`. thinking this would be nice ergonomically.
+34. package declaration aliases and root `std.ArrayList` (implemented)
+  - bare qualified aliases use `Name :: alias package.Member` without adding a keyword
+  - functions/type factories, named types, and globals transparently retain the target identity;
+    mutable global aliases therefore share the original storage
+  - aliases resolve transitively at load time, consume their file-local import, preserve leading-
+    underscore visibility, and diagnose missing, hidden, unavailable, ambiguous, cyclic, or
+    conflicting targets
+  - root `std` re-exports only `ArrayList(T)` for now; operations remain under `std/arraylist`
 
 ## A word on unchecked casts
 

compiler/ast/ast.odin

@@ -251,6 +251,28 @@ Import :: struct {
 	diagnostic: source.Diagnostic_Id,
 }
 
+Declaration_Alias_Kind :: enum u8 {
+	Invalid,
+	Function,
+	Global,
+	Type,
+}
+
+Declaration_Alias :: struct {
+	span:        source.Span,
+	name:        symbol.Id,
+	qualifier:   symbol.Id,
+	member:      symbol.Id,
+	pkg:         Package_Id,
+	file:        File_Id,
+	target_pkg:  Package_Id,
+	target:      u32,
+	kind:        Declaration_Alias_Kind,
+	file_hidden: bool,
+	valid:       bool,
+	diagnostic:  source.Diagnostic_Id,
+}
+
 File :: struct {
 	source:  source.Source_Id,
 	pkg:     Package_Id,
@@ -290,6 +312,7 @@ Module :: struct {
 	functions:  [dynamic]Function,
 	globals:    [dynamic]Global,
 	imports:    [dynamic]Import,
+	aliases:    [dynamic]Declaration_Alias,
 	files:      [dynamic]File,
 	packages:   [dynamic]Package,
 	unsupported: [dynamic]Unsupported,
@@ -309,6 +332,7 @@ init_module :: proc(allocator := context.allocator) -> Module {
 	module.functions.allocator = allocator
 	module.globals.allocator = allocator
 	module.imports.allocator = allocator
+	module.aliases.allocator = allocator
 	module.files.allocator = allocator
 	module.packages.allocator = allocator
 	module.unsupported.allocator = allocator
@@ -360,6 +384,7 @@ destroy_module :: proc(module: ^Module) {
 	delete(module.functions)
 	delete(module.globals)
 	delete(module.imports)
+	delete(module.aliases)
 	delete(module.files)
 	delete(module.packages)
 	delete(module.unsupported)

compiler/checker/checker.odin

@@ -868,6 +868,11 @@ build_symbol_indexes :: proc(checker: ^Checker) {
 			function_count += 1
 		}
 	}
+	for alias in checker.ast_module.aliases {
+		if alias.valid && alias.kind == .Function {
+			function_count += 1
+		}
+	}
 	checker.function_index = make([]Function_Index_Entry, function_count, checker.allocator)
 	function_index := 0
 	for function, id in checker.ast_module.functions {
@@ -877,12 +882,31 @@ build_symbol_indexes :: proc(checker: ^Checker) {
 		checker.function_index[function_index] = Function_Index_Entry{scope=function.pkg, file=function.file, hidden=function.file_hidden, name=function.name, id=ast.function_id(id)}
 		function_index += 1
 	}
+	for alias in checker.ast_module.aliases {
+		if alias.valid && alias.kind == .Function {
+			checker.function_index[function_index] = Function_Index_Entry{scope=alias.pkg, file=alias.file, hidden=alias.file_hidden, name=alias.name, id=ast.Function_Id(alias.target)}
+			function_index += 1
+		}
+	}
 	slice.sort_by(checker.function_index, function_index_less)
 
-	checker.global_index = make([]Global_Index_Entry, len(checker.ast_module.globals), checker.allocator)
+	global_count := len(checker.ast_module.globals)
+	for alias in checker.ast_module.aliases {
+		if alias.valid && alias.kind == .Global {
+			global_count += 1
+		}
+	}
+	checker.global_index = make([]Global_Index_Entry, global_count, checker.allocator)
 	for global, id in checker.ast_module.globals {
 		checker.global_index[id] = Global_Index_Entry{scope=global.pkg, file=global.file, hidden=global.file_hidden, name=global.name, id=ast.global_id(id)}
 	}
+	global_index := len(checker.ast_module.globals)
+	for alias in checker.ast_module.aliases {
+		if alias.valid && alias.kind == .Global {
+			checker.global_index[global_index] = Global_Index_Entry{scope=alias.pkg, file=alias.file, hidden=alias.file_hidden, name=alias.name, id=ast.Global_Id(alias.target)}
+			global_index += 1
+		}
+	}
 	slice.sort_by(checker.global_index, global_index_less)
 
 	checker.import_index = make([]Import_Index_Entry, len(checker.ast_module.imports), checker.allocator)

compiler/loader/loader.odin

@@ -1293,6 +1293,235 @@ find_type_import :: proc(module: ^ast.Module, file: ast.File_Id, alias: symbol.I
 	return ast.INVALID_IMPORT
 }
 
+alias_declarations_conflict :: proc(left_file: ast.File_Id, left_hidden: bool, right_file: ast.File_Id, right_hidden: bool) -> bool {
+	return left_file == right_file if left_hidden && right_hidden else true
+}
+
+alias_conflicts_with_declaration :: proc(module: ^ast.Module, alias: ast.Declaration_Alias) -> bool {
+	for function in module.functions {
+		if function.pkg == alias.pkg && function.name == alias.name &&
+		   alias_declarations_conflict(alias.file, alias.file_hidden, function.file, function.file_hidden) {
+			return true
+		}
+	}
+	for global in module.globals {
+		if global.pkg == alias.pkg && global.name == alias.name &&
+		   alias_declarations_conflict(alias.file, alias.file_hidden, global.file, global.file_hidden) {
+			return true
+		}
+	}
+	for item in module.type_store.nodes {
+		if item.declared && item.pkg == u32(alias.pkg) && item.name == u32(alias.name) &&
+		   alias_declarations_conflict(alias.file, alias.file_hidden, ast.File_Id(item.file), item.file_hidden) {
+			return true
+		}
+	}
+	return false
+}
+
+direct_alias_target :: proc(module: ^ast.Module, pkg: ast.Package_Id, name: symbol.Id) -> (ast.Declaration_Alias_Kind, u32, int) {
+	kind := ast.Declaration_Alias_Kind.Invalid
+	target: u32
+	kinds := 0
+	for function, index in module.functions {
+		if function.pkg == pkg && function.name == name && !function.generated && !function.file_hidden {
+			kind = .Function
+			target = u32(ast.function_id(index))
+			kinds += 1
+			break
+		}
+	}
+	for global, index in module.globals {
+		if global.pkg == pkg && global.name == name && !global.file_hidden {
+			kind = .Global
+			target = u32(ast.global_id(index))
+			kinds += 1
+			break
+		}
+	}
+	if value := types.find_named(&module.type_store, u32(pkg), u32(name)); types.is_valid(value) {
+		if item, ok := types.node(&module.type_store, value); ok && item.declared {
+			kind = .Type
+			target = u32(value)
+			kinds += 1
+		}
+	}
+	return kind, target, kinds
+}
+
+hidden_alias_target_exists :: proc(module: ^ast.Module, pkg: ast.Package_Id, name: symbol.Id) -> bool {
+	for function in module.functions {
+		if function.pkg == pkg && function.name == name && function.file_hidden {
+			return true
+		}
+	}
+	for global in module.globals {
+		if global.pkg == pkg && global.name == name && global.file_hidden {
+			return true
+		}
+	}
+	for item in module.type_store.nodes {
+		if item.declared && item.pkg == u32(pkg) && item.name == u32(name) && item.file_hidden {
+			return true
+		}
+	}
+	for alias in module.aliases {
+		if alias.valid && alias.pkg == pkg && alias.name == name && alias.file_hidden {
+			return true
+		}
+	}
+	return false
+}
+
+find_public_alias :: proc(module: ^ast.Module, pkg: ast.Package_Id, name: symbol.Id) -> int {
+	for alias, index in module.aliases {
+		if alias.valid && alias.pkg == pkg && alias.name == name && !alias.file_hidden {
+			return index
+		}
+	}
+	return -1
+}
+
+resolve_declaration_alias :: proc(state: ^State, index: int, states: []u8) -> bool {
+	alias := &state.module.aliases[index]
+	if !alias.valid {
+		return false
+	}
+	if states[index] == 2 {
+		return alias.kind != .Invalid
+	}
+	if states[index] == 1 {
+		alias.diagnostic = source.addf(
+			state.diagnostics,
+			alias.span,
+			"declaration alias cycle involving '%s'",
+			symbol.resolve(state.symbols, alias.name),
+		)
+		alias.valid = false
+		return false
+	}
+	states[index] = 1
+	defer states[index] = 2
+
+	kind, target, kinds := direct_alias_target(state.module, alias.target_pkg, alias.member)
+	if kinds > 1 {
+		alias.diagnostic = source.addf(
+			state.diagnostics,
+			alias.span,
+			"package member '%s.%s' is ambiguous",
+			symbol.resolve(state.symbols, alias.qualifier),
+			symbol.resolve(state.symbols, alias.member),
+		)
+		alias.valid = false
+		return false
+	}
+	if kinds == 1 {
+		alias.kind = kind
+		alias.target = target
+		return true
+	}
+
+	if target_alias := find_public_alias(state.module, alias.target_pkg, alias.member); target_alias >= 0 {
+		if resolve_declaration_alias(state, target_alias, states) {
+			resolved := state.module.aliases[target_alias]
+			alias.kind = resolved.kind
+			alias.target = resolved.target
+			return true
+		}
+		alias.valid = false
+		return false
+	}
+
+	if hidden_alias_target_exists(state.module, alias.target_pkg, alias.member) {
+		alias.diagnostic = source.addf(
+			state.diagnostics,
+			alias.span,
+			"package member '%s.%s' is file-hidden",
+			symbol.resolve(state.symbols, alias.qualifier),
+			symbol.resolve(state.symbols, alias.member),
+		)
+	} else {
+		alias.diagnostic = source.addf(
+			state.diagnostics,
+			alias.span,
+			"package '%s' has no member '%s'",
+			symbol.resolve(state.symbols, alias.qualifier),
+			symbol.resolve(state.symbols, alias.member),
+		)
+	}
+	alias.valid = false
+	return false
+}
+
+validate_declaration_aliases :: proc(state: ^State) {
+	for &alias, index in state.module.aliases {
+		name := symbol.resolve(state.symbols, alias.name)
+		if alias_conflicts_with_declaration(state.module, alias) {
+			alias.diagnostic = source.addf(state.diagnostics, alias.span, "declaration alias '%s' conflicts with a package declaration", name)
+			alias.valid = false
+			continue
+		}
+		for previous in state.module.aliases[:index] {
+			if previous.pkg == alias.pkg && previous.name == alias.name &&
+			   alias_declarations_conflict(alias.file, alias.file_hidden, previous.file, previous.file_hidden) {
+				alias.diagnostic = source.addf(state.diagnostics, alias.span, "duplicate declaration alias '%s'", name)
+				alias.valid = false
+				break
+			}
+		}
+		if !alias.valid {
+			continue
+		}
+		for import_item in state.module.imports {
+			if import_item.file == alias.file && import_item.alias == alias.name {
+				alias.diagnostic = source.addf(state.diagnostics, alias.span, "declaration alias '%s' conflicts with an import", name)
+				alias.valid = false
+				break
+			}
+		}
+		if !alias.valid {
+			continue
+		}
+
+		import_id := find_type_import(state.module, alias.file, alias.qualifier)
+		if import_id == ast.INVALID_IMPORT {
+			alias.diagnostic = source.addf(state.diagnostics, alias.span, "unknown package alias '%s'", symbol.resolve(state.symbols, alias.qualifier))
+			alias.valid = false
+			continue
+		}
+		state.module.imports[import_id].used = true
+		import_item := state.module.imports[import_id]
+		alias.target_pkg = import_item.target
+		if !import_item.valid || import_item.target == ast.INVALID_PACKAGE ||
+		   int(import_item.target) >= len(state.module.packages) || !state.module.packages[import_item.target].available {
+			alias.diagnostic = source.addf(state.diagnostics, alias.span, "unavailable imported package '%s'", symbol.resolve(state.symbols, alias.qualifier))
+			alias.valid = false
+		}
+	}
+
+	states := make([]u8, len(state.module.aliases), state.allocator)
+	defer delete(states, state.allocator)
+	for _, index in state.module.aliases {
+		_ = resolve_declaration_alias(state, index, states)
+	}
+	for &alias in state.module.aliases {
+		if !alias.valid || alias.kind != .Type {
+			continue
+		}
+		id := types.named(
+			&state.module.type_store,
+			u32(alias.pkg),
+			u32(alias.name),
+			file=u32(alias.file),
+			file_hidden=alias.file_hidden,
+		)
+		if !types.define_alias(&state.module.type_store, id, types.Type(alias.target)) {
+			alias.diagnostic = source.addf(state.diagnostics, alias.span, "duplicate type declaration '%s'", symbol.resolve(state.symbols, alias.name))
+			alias.valid = false
+		}
+	}
+}
+
 canonical_type :: proc(
 	module: ^ast.Module,
 	value: types.Type,
@@ -1456,6 +1685,7 @@ load :: proc(
 		state.root_failed = true
 	}
 	validate_imports(&state)
+	validate_declaration_aliases(&state)
 	canonicalize_types(&module, allocator)
 	return module, !state.root_failed
 }

compiler/parser/parser.odin

@@ -2425,6 +2425,31 @@ parse_distinct :: proc(parser: ^Parser, name: token.Token) {
 
 parse_alias :: proc(parser: ^Parser, name: token.Token) {
 	start := advance(parser)
+	saved := parser.cursor
+	if current(parser).kind == .Identifier && peek(parser).kind == .Dot {
+		qualifier := advance(parser)
+		advance(parser)
+		if current(parser).kind == .Identifier {
+			member := advance(parser)
+			if current(parser).kind == .Newline || current(parser).kind == .Eof {
+				append(&parser.module.aliases, ast.Declaration_Alias{
+					span=span_from(name.span, member.span),
+					name=name.symbol,
+					qualifier=qualifier.symbol,
+					member=member.symbol,
+					pkg=parser.pkg,
+					file=parser.file,
+					target_pkg=ast.INVALID_PACKAGE,
+					file_hidden=file_hidden_name(parser, name),
+					valid=true,
+					diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+				_ = finish_statement(parser)
+				return
+			}
+		}
+	}
+	parser.cursor = saved
 	child := parse_type(parser)
 	id := types.named(&parser.module.type_store, u32(parser.pkg), u32(name.symbol), file=u32(parser.file), file_hidden=file_hidden_name(parser, name))
 	if !types.define_alias(&parser.module.type_store, id, child) {

compiler_tests.odin

@@ -7125,6 +7125,149 @@ imports_do_not_reexport_members :: proc(t: ^testing.T) {
 	testing.expect(t, !state.success)
 }
 
+@(test)
+declaration_aliases_preserve_identity_and_chain :: proc(t: ^testing.T) {
+	root :: "/tmp/brolang-test-declaration-aliases"
+	dep_dir :: root + "/dep"
+	facade_dir :: root + "/facade"
+	top_dir :: root + "/top"
+	app_dir :: root + "/app"
+	output :: "/tmp/brolang-test-declaration-aliases-output"
+	_ = os2.remove_all(root)
+	defer _ = os2.remove_all(root)
+	defer _ = os.remove(output)
+	directories := [?]string{root, dep_dir, facade_dir, top_dir, app_dir}
+	for directory in directories {
+		testing.expect(t, os.make_directory(directory) == nil)
+	}
+	dep_text := `Box func($T type) type {
+	return struct { value T }
+}
+Point :: struct { value i32 }
+counter i32 = 1
+answer func() i32 { return 40 }
+`
+	facade_text := `dep :: import "../dep"
+RenamedBox :: alias dep.Box
+RenamedPoint :: alias dep.Point
+counter :: alias dep.counter
+answer :: alias dep.answer
+_local_answer :: alias dep.answer
+local_answer func() i32 { return _local_answer() }
+Scalar :: alias i32
+MaybePoint :: alias ?@dep.Point
+Concrete :: alias dep.Box(i32)
+`
+	top_text := `facade :: import "../facade"
+Box :: alias facade.RenamedBox
+Point :: alias facade.RenamedPoint
+counter :: alias facade.counter
+answer :: alias facade.answer
+`
+	app_text := `dep :: import "../dep"
+facade :: import "../facade"
+top :: import "../top"
+
+main func() i32 {
+	box top.Box(i32) :: top.Box(i32) { value = 2 }
+	point top.Point :: top.Point { value = 3 }
+	maybe facade.MaybePoint :: none
+	scalar facade.Scalar :: 5
+	top.counter = 7
+	if box.value != 2 or point.value != 3 { return 1 }
+	if scalar != 5 or top.answer() != 40 or facade.local_answer() != 40 or dep.counter != 7 { return 2 }
+	_ = maybe
+	return 0
+}
+`
+	testing.expect(t, os.write_entire_file(dep_dir + "/dep.bro", transmute([]byte)dep_text))
+	testing.expect(t, os.write_entire_file(facade_dir + "/facade.bro", transmute([]byte)facade_text))
+	testing.expect(t, os.write_entire_file(top_dir + "/top.bro", transmute([]byte)top_text))
+	testing.expect(t, os.write_entire_file(app_dir + "/main.bro", transmute([]byte)app_text))
+
+	status := compiler_core.compile_package(app_dir, output)
+	testing.expect_value(t, status, 0)
+	state := run_executable(output)
+	testing.expect_value(t, state.exit_code, 0)
+}
+
+@(test)
+declaration_aliases_diagnose_invalid_targets :: proc(t: ^testing.T) {
+	root :: "/tmp/brolang-test-declaration-alias-errors"
+	dep_dir :: root + "/dep"
+	facade_dir :: root + "/facade"
+	a_dir :: root + "/a"
+	b_dir :: root + "/b"
+	app_dir :: root + "/app"
+	_ = os2.remove_all(root)
+	defer _ = os2.remove_all(root)
+	directories := [?]string{root, dep_dir, facade_dir, a_dir, b_dir, app_dir}
+	for directory in directories {
+		testing.expect(t, os.make_directory(directory) == nil)
+	}
+	dep_text := `visible func() i32 { return 1 }
+_hidden func() i32 { return 2 }
+ambiguous func() i32 { return 3 }
+ambiguous i32 :: 4
+`
+	facade_text := `dep :: import "../dep"
+gone :: import "../gone"
+missing :: alias dep.missing
+hidden :: alias dep._hidden
+unknown :: alias nope.visible
+unavailable :: alias gone.visible
+ambiguous :: alias dep.ambiguous
+duplicate :: alias dep.visible
+duplicate :: alias dep.visible
+collision func() i32 { return 0 }
+collision :: alias dep.visible
+dep :: alias dep.visible
+`
+	a_text := `b :: import "../b"
+value :: alias b.value
+`
+	b_text := `a :: import "../a"
+value :: alias a.value
+`
+	app_text := `facade :: import "../facade"
+a :: import "../a"
+main func() void {}
+`
+	testing.expect(t, os.write_entire_file(dep_dir + "/dep.bro", transmute([]byte)dep_text))
+	testing.expect(t, os.write_entire_file(facade_dir + "/facade.bro", transmute([]byte)facade_text))
+	testing.expect(t, os.write_entire_file(a_dir + "/a.bro", transmute([]byte)a_text))
+	testing.expect(t, os.write_entire_file(b_dir + "/b.bro", transmute([]byte)b_text))
+	testing.expect(t, os.write_entire_file(app_dir + "/main.bro", transmute([]byte)app_text))
+
+	sources := source.init_store()
+	defer source.destroy_store(&sources)
+	diagnostics := source.init_store_diagnostics(&sources)
+	defer source.destroy_diagnostics(&diagnostics)
+	symbols := symbol.init_table()
+	defer symbol.destroy_table(&symbols)
+	module, loaded := loader.load(app_dir, &sources, &diagnostics, &symbols)
+	defer ast.destroy_module(&module)
+	testing.expect(t, loaded)
+	wants := []string{
+		"has no member 'missing'",
+		"is file-hidden",
+		"unknown package alias 'nope'",
+		"unavailable imported package 'gone'",
+		"package member 'dep.ambiguous' is ambiguous",
+		"duplicate declaration alias 'duplicate'",
+		"declaration alias 'collision' conflicts with a package declaration",
+		"declaration alias 'dep' conflicts with an import",
+		"declaration alias cycle",
+	}
+	for want in wants {
+		found := false
+		for diagnostic in diagnostics.items {
+			found = found || strings.contains(diagnostic.message, want)
+		}
+		testing.expect(t, found)
+	}
+}
+
 @(test)
 self_import_via_dot_is_valid :: proc(t: ^testing.T) {
 	output := "/tmp/brolang-test-package-self"

examples/programs/arraylist/main.bro

@@ -1,5 +1,6 @@
 arraylist :: import "@std/arraylist"
 mem :: import "@std/mem"
+std :: import "@std"
 
 _fail_alloc func(_ ?*mut anyopaque, _ usize, _ usize) ?*mut u8 {
 	return none
@@ -25,7 +26,7 @@ _fail_allocator mem.Allocator :: mem.Allocator {
 _noop func() void {}
 
 run func() i32 ! mem.AllocError {
-	values arraylist.ArrayList(i32) = arraylist.init(mem.c_allocator)
+	values std.ArrayList(i32) = arraylist.init(mem.c_allocator)
 	defer arraylist.deinit(&values)
 	if (values.items.len != 0 or values.capacity != 0) return 1
 

std/std.bro

@@ -0,0 +1,3 @@
+import "arraylist"
+
+ArrayList :: alias arraylist.ArrayList

testbed/lexer/main.bro

@@ -1,6 +1,7 @@
-arraylist :: import "@std/arraylist"
-mem :: import "@std/mem"
-c :: import "@ffi/c"
+import "@ffi/c"
+import "@std"
+import "@std/mem"
+import "@std/arraylist"
 
 Kind :: enum(u8) {
 	invalid
@@ -37,7 +38,7 @@ _word_kind func(word []u8) Kind {
 	return .identifier
 }
 
-_append func(tokens @mut arraylist.ArrayList(Token), kind Kind, start, end usize) void ! mem.AllocError {
+_append func(tokens @mut std.ArrayList(Token), kind Kind, start, end usize) void ! mem.AllocError {
 	try arraylist.append(tokens, Token {
 		start = start,
 		length = end - start,
@@ -46,7 +47,7 @@ _append func(tokens @mut arraylist.ArrayList(Token), kind Kind, start, end usize
 	return _
 }
 
-lex func(source []u8, tokens @mut arraylist.ArrayList(Token)) void ! mem.AllocError {
+lex func(source []u8, tokens @mut std.ArrayList(Token)) void ! mem.AllocError {
 	cursor usize = 0
 	while cursor < source.len {
 		value u8 :: source[cursor]
@@ -131,7 +132,7 @@ main func() i32 {
 		`   hello()
 		`}
 
-	tokens arraylist.ArrayList(Token) = arraylist.init(mem.c_allocator)
+	tokens std.ArrayList(Token) = arraylist.init(mem.c_allocator)
 	defer arraylist.deinit(&tokens)
 
 	lex(source, &tokens) catch |_| {

testbed/lexer/std/arraylist/arraylist.bro

@@ -30,7 +30,7 @@ reserve func($T type, list @mut ArrayList(T), minimum_capacity usize) void ! mem
 
 	new_capacity usize = 8
 	if list.capacity >= 8 {
-		half usize :: list.capacity / 2
+		half usize :: div_trunc(list.capacity, 2)
 		if list.capacity > max_value(usize) - half {
 			new_capacity = minimum_capacity
 		} else {

testbed/lexer/std/io/io.bro

@@ -0,0 +1,122 @@
+c :: import "@ffi/c"
+
+ReadError :: enum {
+	read_failed
+}
+
+WriteError :: enum {
+	write_failed
+	no_progress
+}
+
+Io :: struct {
+	context ?*mut anyopaque
+	vtable @IoVTable
+}
+
+IoVTable :: struct {
+	read @func(context ?*mut anyopaque, stream ReadStream, buffer []mut u8) usize ! ReadError
+	write @func(context ?*mut anyopaque, stream WriteStream, bytes []u8) usize ! WriteError
+}
+
+ReadStream :: enum(c_int) {
+	stdin = 0
+}
+
+WriteStream :: enum(c_int) {
+	stdout = 1
+	stderr = 2
+}
+
+Reader :: struct {
+	impl Io
+	stream ReadStream
+}
+
+Writer :: struct {
+	impl Io
+	stream WriteStream
+}
+
+read func(reader Reader, buffer []mut u8) usize ! ReadError {
+	if buffer.len == 0 {
+		return 0
+	}
+	count usize :: try reader.impl.vtable.read(reader.impl.context, reader.stream, buffer)
+	if count > buffer.len {
+		return .read_failed
+	}
+	return count
+}
+
+write func(writer Writer, bytes []u8) usize ! WriteError {
+	if bytes.len == 0 {
+		return 0
+	}
+	count usize :: try writer.impl.vtable.write(writer.impl.context, writer.stream, bytes)
+	if count > bytes.len {
+		return .write_failed
+	}
+	return count
+}
+
+write_all func(writer Writer, bytes []u8) void ! WriteError {
+	offset usize = 0
+	while offset < bytes.len {
+		count usize :: write(writer, bytes[offset..]) catch |err| {
+			return err
+		}
+		if count == 0 {
+			return .no_progress
+		}
+		offset += count
+	}
+	return _
+}
+
+_system_read func(_ ?*mut anyopaque, stream ReadStream, buffer []mut u8) usize ! ReadError {
+	request usize = buffer.len
+	maximum usize :: usize(max_value(c_long))
+	if request > maximum {
+		request = maximum
+	}
+	while true {
+		count c_long :: c.read(c_int(stream), buffer.ptr, c_ulong(request))
+		if count >= 0 {
+			return usize(count)
+		}
+		if c.__error()^ != 4 {
+			return .read_failed
+		}
+	}
+}
+
+_system_write func(_ ?*mut anyopaque, stream WriteStream, bytes []u8) usize ! WriteError {
+	fd c_int :: c_int(stream)
+	request usize = bytes.len
+	maximum usize :: usize(max_value(c_long))
+	if request > maximum {
+		request = maximum
+	}
+	while true {
+		count c_long :: c.write(fd, bytes.ptr, c_ulong(request))
+		if count >= 0 {
+			return usize(count)
+		}
+		if c.__error()^ != 4 {
+			return .write_failed
+		}
+	}
+}
+
+_system_vtable IoVTable :: IoVTable {
+	read = _system_read,
+	write = _system_write,
+}
+
+_system func() Io {
+	return Io {
+		context = none,
+		vtable = &_system_vtable,
+	}
+}

testbed/lexer/std/mem/mem.bro

@@ -61,7 +61,7 @@ alloc func($T type, allocator Allocator, count usize) []mut T ! AllocError {
 	if element_size == 0 {
 		return _empty_slice(T, count)
 	}
-	if count > max_value(usize) / element_size {
+	if count > div_trunc(max_value(usize), element_size) {
 		return .out_of_memory
 	}
 
@@ -86,7 +86,7 @@ realloc func($T type, allocator Allocator, memory []mut T, new_count usize) []mu
 	if element_size == 0 {
 		return _empty_slice(T, new_count)
 	}
-	if new_count > max_value(usize) / element_size {
+	if new_count > div_trunc(max_value(usize), element_size) {
 		return .out_of_memory
 	}
 
@@ -125,7 +125,7 @@ _power_of_two func(value usize) bool {
 
 	current usize = value
 	while current > 1 {
-		half usize = current / 2
+		half usize = div_trunc(current, 2)
 		if half * 2 != current {
 			return false
 		}

testbed/lexer/std/std.bro

@@ -0,0 +1,3 @@
+import "arraylist"
+
+ArrayList :: alias arraylist.ArrayList