Working with Strings

A string is text data — a name, a sentence, a message, or anything made of letters. In AHA! Lang, strings are written between double quotes: "..."

Creating Strings

let nama = "Budi";
let pesan = "Selamat datang di AHA! Lang!";
let kosong = "";

Printing and Concatenating

To join two strings, use +:

let nama = "Budi";
let sapaan = "Halo, " + nama + "!";

print_str(sapaan); // Halo, Budi!

Concatenation works for string with string only — "umur " + 25 will be rejected by the compiler because the types don't match (String + Int).

Escape Sequences

Some special characters need a special way to be written inside a string:

Example:

print_str("Kelas A\tKelas B\nSelesai");

Output:

Kelas A	Kelas B
Selesai

What if you want to print a quote inside a string? Use \":

print_str("Dia berkata, \"AHA!\"");

String Length with len()

The builtin len() returns the number of characters:

print(len("hello"));  // 5
print(len(""));       // 0
print(len("AHA! Lang"));
// 9 — count it yourself!

len() in AHA! Lang is very fast: the string's length is already stored as part of the data, so it's read directly in O(1) — no need to recount.

Comparing Strings

Strings can be compared by content with == and !=:

let jawaban = "aha";

if jawaban == "aha" {        // the result is 1 (true)
    print_str("Benar!\n");
} else {
    print_str("Salah.\n");
}

Comparison compares the content — "aha" == "aha aja" is 0 (false).

Strings Inside Functions

Strings can be passed to functions and returned from functions:

fn seru(teks) {
    teks + "!"
}

fn sapaan_panjang(nama) {
    "Halo, " + nama + "! Semoga harimu menyenangkan."
}

print_str(seru("yuhuu"));              // yuhuu!
print_str(sapaan_panjang("Dina"));     // Halo, Dina! ...

The compiler infers a function's return type automatically.

Summary

Exercises

1. Concatenate "Nama saya " with your name, then print it.
2. Print a three-line poem using a single print_str with \n.
3. Create a function kata_sambutan(jam) that returns "Selamat pagi!" if jam < 12 and "Selamat malam!" otherwise (hint: use if, which you'll learn more deeply in the next lesson — feel free to try it now!).
4. Print the length of your full name with len().

On to Decisions with if / else