0.4.md

March 25, 2024 · View on GitHub

V 0.4

1 July 2023

Improvements in the language

  • Coroutines with a scheduler. Only Linux/macOS for now, requires -use-coroutines and coroutines.sleep() instead of time.sleep(). They work with IO and net, but not with GC for now.
  • spawn now spawns system threads, go spawns coroutines.
  • Static type methods: Foo.new() to replace factory functions like new_foo().
  • Smartcasting with complex conditions: if sum_type is Foo && !sum_type.is_info && get_name(sum_type.info.name) == 'foo' .
  • Functions can now return fixed size arrays.
  • Enum values now can have attributes.
  • Generic functions as function parameters are now supported: fn f[T](x T, i int, f_ Fn[T]) T { .
  • Anonymous structs can no longer have attributes.
  • A new [spawn_stack: 131072] function attribute for controlling the max size of the stack of the spawned threads.
  • Channel pop now works with an or block: ch := <-self.item or { return none }
  • it has been renamed to index in array inits.
  • String interpolation simplified to just '${name}', enforced by vfmt, and updated in the entire code base.
  • go foo() has been replaced with spawn foo() (launches an OS thread, go will be used for upcoming coroutines instead).
  • vfmt now supports // vfmt off and // vfmt on for turning off the formatting locally for short snippets of code. Useful for keeping your carefully arranged matrices intact.
  • Match branch range expressions with consts: match x { const1...const2 {} }
  • Hot code reloading via [live] is now supported in imported modules, not just the main module.
  • Syntax sugar for map inits without needing explicit casts for interfaces: all.children := { "abc": rect, "def": ui.rectangle()}.
  • $embed_file() fixes, including variable args support.
  • none fixes: no longer allowed to be used as a separate type, dump() support, not allowed inside unsafe.
  • Const functions: const y = term.yellow, then println(y('abc')).
  • Builtin type names can no longer be used as identifiers.
  • Generic typeof[T](), sizeof[T](), isreftype[T]() functions.
  • Deprecated -error-limit in favour of the documented -message-limit option.
  • Maps now support aliased keys.
  • Operator overloading now works with reference types.
  • Generic struct inits with nested generic structs and generic optional types are now allowed.
  • During array creation, len: is required when using default values for the array.
  • Optimized one byte []u8 arrays creation.
  • Recursive aliasing is no longer allowed (e.g. type Alias = map[string]Alias).
  • Easier custom error creation: return MyCustomErr{} instead of return IError(MyCustomErr).
  • All floats outputs now have .0 conditionally appended to them to improve clarity.
  • Custom integer enum types: enum Xyz as u64 {.
  • AST transformer fixes and optimizations.
  • Stylistic improvements and bug fixes in vfmt.
  • Casting integers to enums now requires unsafe{}.
  • Improved error and warning messages.
  • Parallel compilation now uses sync.Pool.
  • -skip-unused fixes, soon to be made the default.
  • Anonymous structs.
  • Lots of bug fixes: 90% of all bugs ever submitted are closed.
  • New keyword/type: nil. Only to be used inside unsafe. Replaces voidptr(0).
  • V can now find code in the src/ directory. This allows making V repos much cleaner.
  • Support assert condition, extra_message, where the extra_message will be evaluated and shown if the assertion fails.
  • Operator overloading now works with aliases and generics.
  • Scanner optimizations.
  • Using C's #define is no longer allowed in normal V code, only in .c.v files.

Breaking changes

  • byte deprecated in favor of u8 (byte is automatically converted to u8 by vfmt).
  • json: enums are serialized as strings by default, [json_as_number] attribute can be used for the old behavior.
  • Variable shadowing has been completely banned (previously variable names could conflict with module names).
  • [] is now used for generics instead of <>.
  • Accessing a pointer map value requires an or {} block outside unsafe.
  • Anonymous sumtypes have been removed (deprecated for now) due to complicating the language and the compiler too much.

Checker improvements/fixes

  • Disallow Result type aliases (type Foo = !Bar) and Result in maps (map[key]!Type).
  • Add a missing check for taking address of literal value member.
  • Fixed map initialization for maps with option values.
  • Allow a << none, where a is []?&int.
  • Disallow multiple else branches in a match.
  • Fix index expression with sumtype of array types.
  • Remove hardcoded check for function calls for C.stat, C.sigaction, etc.
  • Fix multiple embedded external module interface.
  • Fix missing check for diff type on map value declaration.
  • Simplify error handling in the checker (#18507).
  • Option alias fixes.
  • Fix alias to struct ptr on struct init.
  • Sumtypes can no longer hold references.
  • Fix a bug checking generic closures.
  • A hard to reach limit of 1 million iterations for resolving all generics.
  • Fix missing check for unwrapped shift operation.
  • Fix enum max value validation.
  • Add a missing mutability check for array.delete calls.
  • Disallow _ = <- quit.
  • Disallow type matching with primitive vars.
  • Warning instead of error for unnecessary brackets in if/match.
  • Include import aliases when checking for import duplicates.
  • Fix inferring generic array type in nested call.
  • Allow casted enum val and const as fixed array size.
  • Disallow multiple return values in const declarations.
  • Fix contains() with array of interfaces.
  • Disallow mut for blank idents.
  • If guards now work with struct fields which are Option functions. Such fields can now also be assigned to other fields/variables.
  • Option receivers can no longer have methods.
  • none can now be cast to all Option types, including aliases.
  • Option references are now supported: ?&Type.
  • Arrays of Options are now allowed.
  • Allow foo := Foo{}, when Foo has an Option field, that is a struct, that has a [required] tag on its fields.
  • Enums can no longer be initialized like structs.
  • Capture variables can no longer shadow anonymous function params.
  • Mixing multi-return results with other types in return statements is no longer allowed.
  • Assigning anonymous structs to named structs is no longer allowed.
  • [required] fields are now checked for embedded structs.
  • Fixed a bug with closures with fixed array variables.
  • Builtin methods first/last/repeat can now be used in custom user types (previously they only worked in builtin arrays).
  • Generic struct initialization no longer needs explicit types to be provided: 
    struct Foo[T, U] {
	a T
	b U
}

foo := Foo{
	a: 2
	b: 'x'
}

println(foo)
  • unsafe: dereferencing nil references is no longer allowed in the following case: 
    a := unsafe { nil }
println(*a)
  • Lots of fixes in the type checker.
  • Int signedness mismatch is now checked: cannot use literal signed integer as u8.
  • Improved type checker: lots of new type checks and fixed checker bugs.
  • Unused last expression in if is now checked.
  • Anonymous structs visibility issues fixed.
  • More type checks.
  • Lots of fixes in shared types.

Standard library

  • json: Enum value string serialization supports [json:'alias'] to change its string values.
  • Struct fields can now be skipped during JSON/ORM serialization via [json:'-'] and [sql:'-'], in addition to [skip]. This allows having custom behavior for different serialization methods.
  • builtin: heap usage API (gc_memory_use() and gc_heap_usage())
  • math.big: refactoring, gcd fixes/improvements, overflow fixes, mod_inverse.
  • flag: fix finalize with multiple shortargs.
  • runtime: add new functions total_memory/0 and free_memory/0.
  • time: small cleanup of parse_iso8601 comments, make the C.strftime declaration forwards compatible
  • stbi: allow customization of number of channels in stbi.load().
  • stbi: add a resize_uint8 function for resizing images in memory.
  • time, x.json2: improve iso8601 time decoding.
  • builtin: zero out internal map/array pointers on m.free(), to reduce the work for the GC mark phase for non escaping maps/arrays, used in hot loops.
  • time: add more detailed error descriptions, add custom format parsing with time.parse_format.
  • sync: add Mutex.destroy and RwMutex.destroy methods.
  • datatypes: add Bloom filter.
  • rand: add missing rand.u16(), update doc comments, add test.
  • builtin: speed up string methods with vmemcpy instead of for loop for copying data.
  • Added new termios module.
  • net.ssl: types using ssl contexts can now be converted to strings via .str()/printed via println().
  • v.reflection: added type symbol info metadata.
  • crypto and math modules have been updated to use Result instead of Option.
  • datatypes.LinkedList[map] now works correctly.
  • urllib.Values.get() now returns an Option.
  • strconv: v_printf() was made private, v_sprintf() was deprecated. String interpolation should be used instead.
  • net.http: mime types have been updated to include all official types.
  • gg: create_image() now returns !Image instead of Image, allowing to handle errors.
  • sokol: errors during image creation no longer result in a panic, but can be handled by the programmer.
  • sokol: macOS apps can now be quit using Cmd+Q.
  • os.hostname() and os.loginname() now return Result.
  • strconv.atoi optimizations.
  • println() now supports arrays with recursive references.
  • termux: support for cross-compilation from termux to other platforms.
  • readline module now works much better on macOS: key navigation, history, etc (now on par with Linux).
  • os: fixed a memleak in getline().
  • os.Process now has a create_no_window option (Windows only).
  • os.Process now has a set_work_folder() method to set the initial working folder of the new child process.
  • math.vec module for generic vector math including 2D, 3D, and 4D vector operations.
  • Builtin stb_image.h used by gg has been updated to the latest v2.28.
  • All of vlib has been updated to use separate Option/Result types.
  • To avoid confusion, all references in the code and documentation to Optional have been replaced with Option.
  • gg.Context pipeline has more effects, including the additive effect.
  • Much cleaner eof checks in os: refactor err == IError(os.Eof{}) to err is os.Eof.
  • Lots of work on x.json2, the pure V json encoder, soon to become official.
  • New v.reflection module for runtime reflection.
  • Improved os.mv(), which now works consistently even across different windows drives/mount points.
  • string.trim_indent(), useful with multi line strings, that start/end with new lines and indentation.
  • Reduced memory consumption in the crypto modules.
  • Official V UI library is now licensed under MIT.
  • Deprecated math.util and math.mathutil have been removed.
  • New time format support: time.format_rfc3339().
  • encoding.html.escape().
  • All public functions in the hash and encoding.base32 modules have been documented.
  • New crypto.pem module.
  • New map.reserve() method.
  • net.ssl has been migrated from a dynamically linked OpenSSL to a statically linked Mbed TLS. This means that V binaries will no longer have an OpenSSL dependency. OpenSSL can still be enabled via -d use_openssl.
  • msgpack module for decoding/encoding msgpack. (v install msgpack)
  • Most of vlib has been updated to use the new Option/Result types.
  • net, net.http, vweb bugs and fixes.
  • QuadTree and RingBuffer types in datatypes.
  • Forward iterator for datatypes.LinkedList<T>, forward and backward iterators for datatypes.DoublyLinkedList<T>.
  • A new maps module, similar to existing arrays. It has generic filter, flatten, invert, to_map, to_array, from_array functions.
  • utf8.is_number(), utf8.is_space() functions.
  • New encoding.base32 module.
  • gg.TouchPoint to differentiate between different types of touch input.
  • str.int() conversion speedup (without -prod).
  • os.mkdir() now has an optional mode parameter.
  • encoding.csv is now generic, supports bools, accepts a custom delimiter, and is compatible with io.Reader/io.Writer.
  • datatypes module now uses operator overloading.
  • All datatypes types can be converted to V arrays.
  • smtp improvements including multiple recipients and base64/utf8 support.
  • arrays.carray_to_varray<T>() for converting C arrays to V arrays.
  • strconv.v_sprintf() has been deprecated in favor of string interpolation.
  • TOML module now supports [toml:...] attributes, just like the JSON module.
  • os.walk() is no longer recursive (still works the same).
  • io has been migrated to Result.
  • Third party window control in Sokol.
  • string.replace_char(), math.round_sig().
  • Improved multiplication performance in math.big.

Web

  • The builtin websocket library is now thread safe.
  • Enhanced builtin csrf protection in vweb.
  • vweb: ability to set and get values on vweb.Context.
  • vweb: support for host specific static files.
  • vweb: host option added to controller, and a new host attribute.
  • vweb: middleware docs improved; same with docs for [vweb_global] and shared.
  • vweb: return 404 on file not found.
  • net.http: copy IANA's list of methods to the http.Method enum.
  • net.conv: use a pure V implementation instead of C.hton etc.
  • net.html: get_tag() methods to find first tag occurrence.
  • net.html: fixed text parsing for inline tags.
  • net.html: fix parsing of nested quoted strings in code tags.
  • picoev: FreeBSD support.
  • vweb now supports live page reloading. The web app is instantly updated in the browser (no need to refresh the page) every time a .v or a .html file is changed.
  • vweb is now significantly faster and more stable under load, due to a new multithreaded worker pool, which is much more efficient at spreading the workload among all threads equally.
  • vweb now supports middleware.
  • vweb now supports controllers. It's now possible to have multiple app structs to better separate logic.
  • vweb now supports overridable .not_found() method for custom 404 pages in vweb.
  • vweb now uses database pool.
  • Fixed multipart form parsing in vweb.
  • Improved vweb stability under load.
  • vweb.csrf module.
  • net.urllib ipv6 support.
  • net.Http.Response.text renamed to body.
  • net.websocket timeout is now configurable.

ORM

  • Fixed a foreign key bug that could result in an extra insert.
  • Comptime bug with [skip] and [sql:'-'] fixed.
  • Checker error for unsupported field types.
  • Allow structs without the id field, more flexible primary keys.
  • Improved docs and examples.
  • Uninitialized structs are no longer inserted into related tables.
  • All ORM queries now return ![] (Result of an array). This allows handling/propagating DB errors and simplifies working with ORM (one way).
  • Many ORM improvements: type checks for limit/offset/order by/where; support of reference objects in insert; struct fields can be used with limit/offset; Connection interface.
  • ORM now supports the like operator: 
    users := sql db {
    select from User where name like 'Bob%'
}
  • A new -d trace_orm option to see all SQL queries generated and used by V ORM and -d trace_pg_error to trace PG errors.
  • Various ORM fixes and improvements, including string interpolation support, type checks, fn calls in where.
  • Support parenthesized expressions like select from User where (name == 'Sam' && is_customer == true) || id == 1.
  • ORM functions now return Result, so the errors can be handled.

Database drivers

  • mysql: TIMESTAMP support.
  • mysql: allocate memory for each string and blob dynamically depending on its value length.
  • mysql: add the ability to commit transactions.
  • VFS support in the builtin sqlite module; sqlite.get_affected_rows_count().
  • Improved pg compatibility with older PostgreSQL versions before 2014.
  • sqlite, pg, mysql have been moved to db.sqlite, db.pg, db.mysql.

Native backend

  • Refactoring, splitting large files into multiple.
  • Lots of fixes and new features in the native backend, including making codegen logic platform independent.
  • Operator support for floats, multi return.
  • Lots of native backend improvements, including library calls, comptime conditionals, enums, method definitions/calls, structs.
  • Major improvements to the fast native backend including linking support on Linux. The goal is to be able to self host V soon.

V interpreter

  • Some further interpreter work.

C backend

  • Fix code generation for generic unions.
  • Fix [N]chan (fixed arrays of channels).
  • Fix nested fixed array instantiation.
  • Fix fixed array of map.
  • Fix stringification of usize struct fields (before, they were treated as 32 bit signed numbers).
  • Now code generated by the С backend, can be compiled by a C++20 compiler.
  • C backend does not generate unused interface functions now.
  • Parallelized cc step. Speeds up -prod and clang/gcc compilation by 300-500% (depending on the number of cores). Experimental and hidden behind a -parallel-cc flag, soon to be the default.
  • Intel C compiler support.
  • Go backend fixes.
  • #preinclude for low level C interop.

WASM backend

  • A new pure WASM backend, based on binaryen, a WASM builtin module, and a pure V WASM serialization library.

Comptime

  • A new $res comptime function to get returned value in defer block (#18382).
  • Fix comptimeselector option propagation.
  • A mutability check for comptime assignments.
  • Fix comptime assigning to sumtype or indexexpr.
  • Make comptime calls work with or-block.
  • Compile-time interface fields evaluation.
  • Compile-time enum evaluation: 
    $for item in MyEnum.fields {
    println(item.value)
    println(item.name)
}
  • Added $option as a compile-time reflection type representing an any Option type.
  • All special compile-time reflection types are now lowercase ($int, $enum, $option, etc).
  • Improved compile time checks, like $if x is Type {; $if T in [$Array, $Struct, $Alias, $Function] {.
  • $for in works with alias types.
  • New comptime features for fields: field.is_<field>, field.is_alias, field.is_enum.

Compiler CLI

  • v share file.v for sharing code via the playground.
  • v up speed up for when it hasn't been run for a long time (vc/ bootstrapping has been optimized).
  • v init no longer overwrites existing src/main.v.
  • v self now uses a faster TCC backend on macOS (Intel/Apple Silicon), just like on Windows/Linux.
  • A new command line flag -e for running short V programs on command line: v -e "println(2+5)" ( works just like in Perl).
  • A new -ldflags option, in addition to -cflags. Works just like LDFLAGS in C.

OS support

  • Added basic QNX support.
  • Installation instructions for using V on NixOS.
  • Better make support for OpenBSD.
  • Much improved experience for v install pcre on Windows (it now bundles its own .c files, so it compiles cleanly, even if the platform does not have another pcre package installed).
  • V can now be compiled with tcc on latest macOS and Apple Silicon.
  • Removed the need for the [console] attribute in Windows GUI apps.
  • More precise WINAPI declarations for easier integration on Windows.
  • More CI tests on FreeBSD.
  • Full termux support via $if termux {, more predictable logging on Android.
  • Older macOS support (<10.12).
  • Windows code has been removed from v.c distributed on non-Windows systems. (v_windows.c is used on Windows.)

Tooling

  • A new VPM site: vpm.vlang.io. A better design, discoverability of packages, descriptions, most downloaded packages etc.
  • vpm: installation of mixed modules.
  • v ls --install -p D:\path\vls.exe to install a local vls executable.
  • vdoc: highlight comments with gray color.
  • vet: allow vetting files with global variables.
  • Make util.launch_tool/3 more robust, by recompiling V tools always in a known current working folder.
  • Lots of documentation/readme improvements.
  • Lots of playground improvements: play.vlang.io, including a really cool feature: "Show generated C code".
  • "Is V still fast?" web-page has been sped up by splitting the result table into multiple years.
  • GitHub Copilot summaries in PRs.
  • fast.vlang.io fixes & improvements, new server.
  • New official IntelliJ plugin: https://intellij-v.github.io.
  • Lots of new language documentation, a nicer table of contents.
  • Improved documentation for most of the vlib modules
  • make.bat & v up improvements on Windows.
  • TeamCity test runner support via v -test-runner teamcity foo_test.v.
  • CI optimizations for faster runs.
  • New official AdventOfCode repo with AOC solutions, also added to CI.
  • More detailed timings in v -show-timings.
  • v new <name> web for quickly scaffolding new web projects.
  • New stunning playground with an improved look and feel, a much better and more responsive editor, code sharing by link, more convenient keyboard control, reusability for potential embedding: https://play.vlang.io.
  • Improved call tracing via -trace-calls.
  • Lots of documentation improvements, including a better documentation of the recent Option/Result split.
  • V REPL: Home/End keys support. Lots of clean up.
  • DOOM is now translated/compiled and launched on CI servers. A screenshot of the running game is made via vgret and is compared to the expected result.
  • VLS performance improvements, especially on Windows.
  • v ls tool for installing, for updating, and for launching VLS (V Language Server).
  • v doc now has syntax highlighting.