.zar and .zex Files

zolo build supports two ZIP-based output formats:

.zar (Zolo ARchive) — library archive. Bundles bytecode and assets to be reused as a dependency by other projects.
.zex (Zolo EXecutable archive) — executable archive. Packages the entire program and can be run with zolo run.

A .zar file is generated with the --emit zar flag. The file can still be run directly with zolo run (top-level statements execute), but its main purpose is to be linked as a dependency:

pub fn exports symbols; zolo build --emit zar generates the reusable archive.

01-zar-library.zolo

Playground

// Feature: library archive — `zolo build --emit zar`
// Syntax: `zolo build file.zolo --emit zar`
// When to use: package reusable code as a `.zar` (Zolo ARchive) that
//   other Zolo programs can depend on / link against.

// Run:
//   zolo build 31-distribution/01-zar-library.zolo --emit zar
//   # -> Built target/01-zar-library-0.0.0.zar (...)
//
// A `.zar` is a ZIP-based container (alongside `.zbc` bytecode and the
// `.zex` executable archive). It bundles the module's bytecode + any
// assets/manifest so it can be shipped and reused as a dependency.

pub fn add(a: int, b: int) -> int {
  return a + b
}

pub fn mul(a: int, b: int) -> int {
  return a * b
}

// A library file still runs on its own (the top-level statements execute):
print("add(2, 3) =", add(2, 3))
print("mul(2, 3) =", mul(2, 3))

// See ../../../specs/zar-zex-archives.md for the container format.
// expected:
//   add(2, 3) =	5
//   mul(2, 3) =	6

Requires the Zolo CLI/host — open in the playground or run locally.

To package a program as a portable executable, use --emit zex. The resulting .zex still depends on zolo being installed on the target machine — but eliminates the need to distribute the source code:

zolo build --emit zex packages it; zolo run target/app.zex runs it without source.

02-zex-executable.zolo

Playground

// Feature: executable archive — `zolo build --emit zex`
// Syntax: `zolo build file.zolo --emit zex`
// When to use: ship a single runnable `.zex` (Zolo EXecutable archive)
//   that `zolo run` can execute directly.

// Run:
//   zolo build 31-distribution/02-zex-executable.zolo --emit zex
//   # -> Built target/02-zex-executable-0.0.0.zex (...)
//   zolo run target/02-zex-executable-0.0.0.zex
//   # -> runs the program below
//
// A `.zex` packages bytecode + assets into one ZIP-based file. Unlike a
// native `zolo build`, a plain `.zex` still needs the `zolo` runtime to
// execute it — use `--standalone` (see 03) to embed the runtime and make
// it self-contained.

print("This program was shipped as a .zex archive.")
for i in 1..=3 {
  print("  tick", i)
}

// expected:
//   This program was shipped as a .zex archive.
//     tick	1
//     tick	2
//     tick	3

Requires the Zolo CLI/host — open in the playground or run locally.

Challenge

Create a util.zolo file with a pub fn greet(name: str) -> str function and compile it with --emit zar. Then write a second file that imports the generated .zar and calls greet.