Quickstart

Vela is a Stage-0 from-scratch interpreter today, so this section is anchored in what the seed actually runs.

1. Build and run

From the interpreter repo:

cargo build --release
./target/release/vela run examples/hello.vela
./target/release/vela repl

The same commands are documented in ../README.md and mirror platform/apps/stretchdevdocs-web/.sources/vela/docs/README.md.

2. Hello world

# hello.vela
print("Hello, Vela!")

Hello, Vela!

3. One binding style

Bindings are immutable by default:

x = 1
x = 2

vela: line 2: cannot reassign immutable binding `x` (declare it with `mut`)

Use mut when a value must be reassigned.

mut count = 0
count = count + 1

4. Source layout pattern

The command-line takes a .vela file:

vela run examples/hello.vela
vela run examples/calculator.vela

vela run <file> and vela <file> are both shown as valid in the docs; both execute the same file.

5. Built-in command-line args

ARGV is a global list:

if ARGV.len == 0:
    print("no arguments given.  try:  vela run examples/args.vela Alice Bob")
else:
    print("got", ARGV.len, "argument(s):")
    for name in ARGV:
        print("  hello,", name)

6. Imports in the seed

Stage-0 supports importing another file with use "path":

use "lib/greet.vela"

print(greet("Vela"))

The reference says it is loaded once and use paths are resolved by path string.

7. Next

• Language Tour for the first 20 minutes walkthrough.
• Syntax & Types to learn each language form and evaluation rule.
• Design Notes for what is still planned in the self-hosted compiler.