q

A simple programming language.

Features

• Fast compilation
• Small binaries
• High performance

Installation

git clone https://git.akyoto.dev/cli/q
cd q
go build

Usage

Build a Linux x86-64 ELF executable from examples/hello and run it:

./q run examples/hello

Todo

Compiler

• Tokenizer
• Scanner
• Functions
• Variables
• Error messages
• Expression parser
• Function calls
• Parallel compilation
• Syscalls
• Variable lifetimes
• Branches
• Loops
• Hexadecimal, octal and binary literals
• Escape sequences
• Multiple return values
• Type system
• Type operator ?
• Data structures
• Slices
• Floating-point arithmetic
• Error handling
• Threading library
• Self-hosted compiler

Keywords

• assert
• else
• for
• if
• import
• loop
• return
• switch

Optimizations

• Exclude unused functions
• Constant folding
• Function call inlining
• Loop unrolls

Linter

• Unused variables
• Unused parameters
• Unused imports
• Unnecessary newlines
• Ineffective assignments

Operators

• =, :=
• +, -, *, /, %
• +=, -=, *=, /=, %=
• &, |, ^
• &=, |=, ^=
• <<, >>
• <<=, >>=
• ==, !=, <, <=, >, >=
• &&, ||
• !, -

Architecture

• arm64
• riscv
• x64

Platform

• Linux
• Mac
• Windows

Documentation

main.go

Entry point. It simply calls cli.Main which we can use for testing.

src/cli/Main.go

The command line interface expects a command like build as the first argument. Commands are implemented as functions in the src/cli directory. Each command has its own set of parameters.

src/cli/Build.go

The build command creates a new Build instance with the given directory and calls the Run method.

If no directory is specified, it will use the current directory.

If the --dry flag is specified, it will perform all tasks except the final write to disk. This flag should be used in most tests and benchmarks to avoid needless disk writes.

q build
q build examples/hello
q build examples/hello --dry

Adding the -a or --assembler flag shows the generated assembly instructions:

q build examples/hello -a

Adding the -v or --verbose flag shows verbose compiler information:

q build examples/hello -v

src/build/Build.go

The Build type defines all the information needed to start building an executable file. The name of the executable will be equal to the name of the build directory.

Run starts the build which will scan all .q source files in the build directory. Every source file is scanned in its own goroutine for performance reasons. Parallelization here is possible because the order of files in a directory is not significant.

The main thread is meanwhile waiting for new function objects to arrive from the scanners. Once a function has arrived, it will be stored for compilation later. We need to wait with the compilation step until we have enough information about all identifiers from the scan.

Then all the functions that were scanned will be compiled in parallel. We create a separate goroutine for each function compilation. Each function will then be translated to generic assembler instructions.

All the functions that are required to run the program will be added to the final assembler. The final assembler resolves label addresses, optimizes the performance and generates the specific x86-64 machine code from the generic instruction set.

src/core/Function.go

This is the "heart" of the compiler. Each function runs f.Compile which organizes the source code into an abstract syntax tree that is then compiled via f.CompileAST. You can think of AST nodes as the individual statements in your source code.

src/ast/Parse.go

This is what generates the AST from tokens.

src/expression/Parse.go

This is what generates expressions from tokens.

Tests

go test ./... -v -cover

Benchmarks

go test ./tests -bench=. -benchmem

License

Please see the license documentation.

Copyright

© 2023 Eduard Urbach