A statically-typed functional programming language with structural typing, pattern matching, lightweight processes, typed message passing, and postfix-based syntax.

Try Quiver in the online REPL

// Define a recursive list type
list<t> : Nil | Cons[t, &];

// Import standard library
math = %"math",

// Compute the sum of a list using tail recursion
sum' = #[list<int>, int] {
  | ~> =[Nil, acc] => acc
  | ~> =[Cons[head, tail], acc] => {
     math.add[head, acc] ~> &[tail, ~]
  }
},

sum = #list<int> { ~> sum'[~, 0] },

// Build and sum a list
xs = Cons[1, Cons[2, Cons[3, Nil]]],
xs ~> sum  // 6

Run the example above in the REPL (quiv repl, or at quiver.run), or run the executable version in examples/sum.qv with quiv run examples/sum.qv.

Language features

• Postfix syntax: Data flows left-to-right through transformations
• Structural typing: Types are defined by their structure, not their names
• Pattern matching: Destructure and branch on values with expressive pattern syntax
• Union types: Model complex data with algebraic types
• Tail recursion: Efficient recursive algorithms via explicit tail-calls
• Concurrent processes: Erlang-inspired lightweight processes with typed message passing

See docs/spec.md for the complete language specification.

Getting started

Building from source

Clone the repository and build:

git clone https://github.com/joefreeman/quiver.git
cd quiver
cargo build --release

The compiled binary will be at target/release/quiv.

Quick start

Run the REPL:

quiv repl

Execute a Quiver program:

quiv run program.qv

CLI commands

• quiv repl - Start an interactive REPL session
• quiv run [FILE] - Run a Quiver program (.qv source or .qx bytecode)
  • -e, --eval <CODE> - Execute code directly from the command line
• quiv compile [FILE] - Compile source to bytecode
  • -o, --output <FILE> - Write output to file
  • -d, --debug - Include debug information in bytecode
  • -e, --eval <CODE> - Compile code directly from the command line
• quiv inspect <FILE> - Inspect compiled bytecode structure

All commands support reading from stdin when no file is specified.

REPL commands

Within the REPL:

• \? - Show help message
• \q - Exit the REPL
• \! - Reset the environment
• \v - List all variables
• \p - List all processes
• \p X - Inspect process with ID X

License

MIT