KUJO THE COURSESTAGE 1 / Kujo foundations · LESSON 02
Where you are
You have a development goal; now establish an execution environment you can identify and reproduce. All captured course results use the official Kujo 1.3.1 release binary, not an unreleased checkout that happens to report the same version.
Install and identify
Download the archive for your operating system and architecture from the 1.3.1 release. Verify it against the published SHA-256 file before extracting it. Put the extracted kujo binary in a directory on your PATH. On Windows, use kujo.exe and verify the archive with Get-FileHash -Algorithm SHA256. On macOS use shasum -a 256; on Linux use sha256sum. Compare the full hash, not a prefix.
Run kujo --version and kujo --help. If your shell finds an older binary first, inspect your PATH before changing source code. The course verifier refuses versions other than 1.3.1, making version drift visible.
Runtime contract
Save the example in a UTF-8 file ending in .kujo. Run kujo check examples/02.kujo before execution. The normal command uses the VM. For an explicit comparison use kujo run --interpreter examples/02.kujo. Interpreter mode is a fallback and diagnostic path, not a prerequisite for ordinary modules.
JIT remains experimental and opt-in. Do not add --jit to a beginner workflow or use its performance as the baseline contract. Browser/WASM targeting is deferred; the online course therefore shows tested source and captured output instead of sending arbitrary code to a server.
Read diagnostics as feedback
A syntax error occurs before execution; changing capabilities cannot fix it. A runtime error happens after parsing and may depend on input. A command-line usage error means the invocation itself was invalid. Later you will consume their distinct exit codes in automation.
Editor setup
Use an editor integration that starts kujo lsp over standard input/output. Confirm the server binary is the same release your terminal uses. Keep diagnostics in the language server rather than writing editor-specific approximations of Kujo syntax. Lesson 21 returns to navigation, completion, and protocol limits.
Working example
func greet() {
print("Kujo Kujo!")
}
greet()
Run it
From the course repository root, use the pinned Kujo 1.3.1 runtime.
kujo check examples/02.kujo
kujo run --untrusted examples/02.kujo
Captured output
Kujo Kujo!
Break it and diagnose it
The parameter list is malformed. This is a parser failure; the body never runs.
func greet( {
print("Kujo Kujo!")
}
kujo run --untrusted examples/02-break.kujo
Exit status: 3. Captured diagnostic:
[KUJOPARSE001] [parser] error: Expected ')' to close function parameter list but found Punctuation('{')
--> examples/02-break.kujo:1:13
= help: Fix the parse error and rerun Kujo.
[KUJOPARSE001] [parser] error: Expected ':' in dictionary literal
--> examples/02-break.kujo:3:1
= help: Fix the parse error and rerun Kujo.
Exercise
Install and identify the runtime, check and run the greeting, then run the interpreter comparison. Save the version and both outputs. Introduce a missing closing brace and identify the source location in the diagnostic.
Checkpoint
- I can identify the exact binary I run.
- I use the VM as the normal execution path.
- I can separate a parser error from a runtime error.
Verified 2026-09-06 · Official Kujo 1.3.1 release · Source contract · Download example