Hello, World — Prism

Every language has one. Ours is a builtin and a string concatenation.

Create a file called hello.prism:

fn main() {
    let name = "developer"
    println("Hello, " + name + "!")
}

Run it:

prism run hello.prism

Hello, developer!

What just happened

Let’s walk through each part.

Every executable needs a main function. fn declares a function; the empty parentheses say it takes no arguments.

main may omit its return type — the compiler treats a missing return type as no value.

let declares an immutable binding. The type is inferred: name is a str. To rebind a value, use let mut:

let mut count = 0
count += 1

println is a builtin — no module import needed. Strings are concatenated with +; there is no {} interpolation in v0.1.0.

prism run is for iteration. When you want a binary, build one:

prism build hello.prism
./hello

The output is a single static executable with no runtime dependency. On Linux you can copy it to a machine without Prism installed and it will run.

Note: by default prism build produces a binary named after the source file. Use prism build -o myapp to choose the output name.

Next: Syntax — or skip ahead to PrismX UI if you came for the interface part.