zig/README.md

zig lang

An experiment in writing a low-level programming language with the intent to replace C. Zig intends to be a small language, yet powerful enough to write optimal, readable, safe, and concise code to solve any computing problem.

Porting a C project to Zig should be a pleasant experience - every C feature needs a corresponding Zig feature which solves the problem equivalently or better.

Zig is not afraid to roll the major version number of the language if it improves simplicity, fixes poor design decisions, or adds a new feature which compromises backward compatibility.

Goals

• Completely compatible with C libraries with no wrapper necessary.
• In addition to creating executables, creating a C library is a primary use case. You can export an auto-generated .h file.
• Do not depend on libc unless explicitly imported.
• Provide standard library which competes with the C standard library and is always compiled against statically in source form.
• Generics so that one can write efficient data structures that work for any data type.
• Ability to run arbitrary code at compile time and generate code.
• A type which represents an error and has some convenience syntax with regards to resources.
• Defer statement.
• Memory zeroed by default, unless you explicitly ask for uninitialized memory.
• Eliminate the need for configure, make, cmake, etc.
• Eliminate the need for header files (when using zig internally).
• Tagged union enum type.
• Resilient to parsing errors to make IDE integration work well.
• Source code is UTF-8.
• Ability to mark functions as test and automatically run them in test mode. This mode should automatically provide test coverage.
• Friendly toward package maintainers.
• Ability to declare dependencies as Git URLS with commit locking (can provide a tag or sha1).
• Include documentation generator.
• Shebang line OK so language can be used for "scripting" as well.

Current Status

• Core language features are lacking such as structs, enums, loops.
• Only Linux is supported.
• Only building for the native target is supported.
• Have a look in the examples/ folder to see some code examples.
• Optimized machine code that Zig produces is indistinguishable from optimized machine code produced from equivalent C program.
• Zig can generate dynamic libraries, executables, object files, and C header files.
• The binaries produced by Zig have complete debugging information so you can, for example, use GDB to debug your software.

Roadmap

• structs
• loops
• enums
• calling external variadic functions and exporting variadic functions
• inline assembly and syscalls
• conditional compilation and ability to check target platform and architecture
• main function with command line arguments
• void pointer constant
• sizeof
• static initializers
• assert
• function pointers
• running code at compile time
• standard library print functions
• panic! macro or statement that prints a stack trace to stderr in debug mode and calls abort() in release mode
• unreachable codegen to panic("unreachable") in debug mode, and nothing in release mode
• implement a simple game using SDL2
• implement a GUI with several types of widgets and investigate whether we need any OOP features

Building

mkdir build
cd build
cmake ..
make
./run_tests

Primitive Numeric Types:

zig	C equivalent	Description
bool	bool	unsigned 1-bit integer
i8	int8_t	signed 8-bit integer
u8	uint8_t	unsigned 8-bit integer
i16	int16_t	signed 16-bit integer
u16	uint16_t	unsigned 16-bit integer
i32	int32_t	signed 32-bit integer
u32	uint32_t	unsigned 32-bit integer
i64	int64_t	signed 64-bit integer
u64	uint64_t	unsigned 64-bit integer
f32	float	32-bit IEE754 floating point
f64	double	64-bit IEE754 floating point
f128	long double	128-bit IEE754 floating point
isize	intptr_t	signed pointer sized integer
usize	uintptr_t	unsigned pointer sized integer
c_char	char	for API compatibility with C
c_schar	signed char	for API compatibility with C
c_uchar	unsigned char	for API compatibility with C
c_short	short	for API compatibility with C
c_ushort	unsigned short	for API compatibility with C
c_int	int	for API compatibility with C
c_uint	unsigned int	for API compatibility with C
c_long	long	for API compatibility with C
c_ulong	unsigned long	for API compatibility with C
c_longlong	long long	for API compatibility with C
c_ulonglong	unsigned long long	for API compatibility with C

Grammar

Root : many(TopLevelDecl) token(EOF)

TopLevelDecl : FnDef | ExternBlock | RootExportDecl | Use

Use : many(Directive) token(Use) token(String) token(Semicolon)

RootExportDecl : many(Directive) token(Export) token(Symbol) token(String) token(Semicolon)

ExternBlock : many(Directive) token(Extern) token(LBrace) many(FnDecl) token(RBrace)

FnProto : many(Directive) option(FnVisibleMod) token(Fn) token(Symbol) ParamDeclList option(token(Arrow) Type)

Directive : token(NumberSign) token(Symbol) token(LParen) token(String) token(RParen)

FnVisibleMod : token(Pub) | token(Export)

FnDecl : FnProto token(Semicolon)

FnDef : FnProto Block

ParamDeclList : token(LParen) list(ParamDecl, token(Comma)) token(RParen)

ParamDecl : token(Symbol) token(Colon) Type

Type : token(Symbol) | token(Unreachable) | token(Void) | PointerType | ArrayType

PointerType : token(Star) (token(Const) | token(Mut)) Type

ArrayType : token(LBracket) Type token(Semicolon) Expression token(RBracket)

Block : token(LBrace) list(option(Statement), token(Semicolon)) token(RBrace)

Statement : Label | VariableDeclaration token(Semicolon) | NonBlockExpression token(Semicolon) | BlockExpression

Label: token(Symbol) token(Colon)

VariableDeclaration : token(Let) option(token(Mut)) token(Symbol) (token(Eq) Expression | token(Colon) Type option(token(Eq) Expression))

Expression : BlockExpression | NonBlockExpression

NonBlockExpression : ReturnExpression | AssignmentExpression

AssignmentExpression : BoolOrExpression token(Equal) BoolOrExpression | BoolOrExpression

BlockExpression : IfExpression | Block

BoolOrExpression : BoolAndExpression token(BoolOr) BoolAndExpression | BoolAndExpression

ReturnExpression : token(Return) option(Expression)

IfExpression : token(If) Expression Block option(Else | ElseIf)

ElseIf : token(Else) IfExpression

Else : token(Else) Block

BoolAndExpression : ComparisonExpression token(BoolAnd) ComparisonExpression | ComparisonExpression

ComparisonExpression : BinaryOrExpression ComparisonOperator BinaryOrExpression | BinaryOrExpression

ComparisonOperator : token(BoolEq) | token(BoolNotEq) | token(BoolLessThan) | token(BoolGreaterThan) | token(BoolLessEqual) | token(BoolGreaterEqual)

BinaryOrExpression : BinaryXorExpression token(BinOr) BinaryXorExpression | BinaryXorExpression

BinaryXorExpression : BinaryAndExpression token(BinXor) BinaryAndExpression | BinaryAndExpression

BinaryAndExpression : BitShiftExpression token(BinAnd) BitShiftExpression | BitShiftExpression

BitShiftExpression : AdditionExpression BitShiftOperator AdditionExpression | AdditionExpression

BitShiftOperator : token(BitShiftLeft | token(BitShiftRight)

AdditionExpression : MultiplyExpression AdditionOperator MultiplyExpression | MultiplyExpression

AdditionOperator : token(Plus) | token(Minus)

MultiplyExpression : CastExpression MultiplyOperator CastExpression | CastExpression

MultiplyOperator : token(Star) | token(Slash) | token(Percent)

CastExpression : PrefixOpExpression token(as) Type | PrefixOpExpression

PrefixOpExpression : PrefixOp FnCallExpression | FnCallExpression

FnCallExpression : PrimaryExpression token(LParen) list(Expression, token(Comma)) token(RParen) | PrimaryExpression

PrefixOp : token(Not) | token(Dash) | token(Tilde)

PrimaryExpression : token(Number) | token(String) | KeywordLiteral | GroupedExpression | token(Symbol) | Goto

Goto: token(Goto) token(Symbol)

GroupedExpression : token(LParen) Expression token(RParen)

KeywordLiteral : token(Unreachable) | token(Void) | token(True) | token(False)

Operator Precedence

x()
!x -x ~x
as
* / %
+ -
<< >>
&
^
|
== != < > <= >=
&&
||
=