Your first Kiroha program

Let's write a small program and run it. You only need a text editor and a terminal. If Kiroha isn't installed yet, the installation guide will help you get ready.

1. Check that Kiroha is ready

Open a terminal and run:

kiroha --version

You should see one line of JSON that includes kiroha-rs/0.6.0 and the language version 0.6.0. If your shell says command not found, try:

export PATH="$HOME/.local/bin:$PATH"

Then run the version command again. More installation help.

2. Save a small program

Create a file called hello.kiroha in your editor and paste this:

greeting = "Hello";
name = "Kiroha";
greeting + ", " + name + "!"

The first two lines give names to values. A semicolon separates one item from the next. The last expression is the program's result.

Newlines make the program easier to read, but don't replace semicolons. You can leave a semicolon after the last expression too.

3. Check and run it

In the folder where you saved the file, run:

kiroha check hello.kiroha --json

This checks the syntax and names without running your program. A successful check looks like this:

{"protocol":"kiroha-cli/1","ok":true,"phase":"check"}

Now run it:

kiroha run hello.kiroha --json

The result is:

{"protocol":"kiroha-cli/1","ok":true,"result":{"t":"string","v":"Hello, Kiroha!"}}

The wrapper is there so people and other programs can read results reliably. ok: true means the program succeeded. Inside result, t is the value's kind and v is its value. Here, the value is the string Hello, Kiroha!. The --json flag is required in this release.

4. Try a number

Replace the contents of hello.kiroha with:

0.1 + 0.2

Run the same command again. The result now contains:

{"t":"number","v":"0.3"}

Kiroha uses exact decimal numbers. The wire format stores a number's spelling as a string so large or precise numbers survive the trip through JSON. The Kiroha value itself is a number.

5. Give a calculation a name

Try this in the same file:

fun add_tax(price:num)
  tax = price * 0.1;
  price + tax
end fun add_tax

add_tax(20)
// 22

fun add_tax(price:num) starts the function. end fun add_tax closes it with the same name. Between them, tax is a local value, and the last expression becomes the function's result.

You've now saved, checked and run a program, read its result, and written a function. A good next step is Functions, step by step, or Work with data if you have a list you'd like to transform.

If your result looks different

Check that the file was saved, and that the terminal is in the same folder. If Kiroha reports an error, this short guide explains the message and a few common fixes.