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Examples

Explore real Ora snippets and repository fixtures that reflect the current implementation.

Simple Storage​

contract SimpleStorage {
    storage var value: u256;

    pub fn set(new_value: u256) {
        value = new_value;
    }

    pub fn get() -> u256 {
        return value;
    }
}

Region Transitions (validated)​

storage var s: u32;

fn f() -> void {
    let x: u32 = s;  // storage -> stack read
    s = x;           // stack -> storage write
}

Error Unions (partial)​

error InsufficientBalance;
error InvalidAddress;

fn transfer(to: address, amount: u256) -> !u256 | InsufficientBalance | InvalidAddress {
    if (amount == 0) return error.InvalidAddress;
    if (balance < amount) return error.InsufficientBalance;
    balance -= amount;
    return balance;
}

Switch (basic expression)​

fn classify(x: u32) -> u32 {
    switch (true) {
        x == 0 => 0,
        x < 10 => 1,
        else   => 2,
    }
}

Switch (advanced)​

1) Statement form with expression arms​

fn tally(kind: u32) -> void {
    var counter: u32 = 0;
    switch (kind) {
        0 => counter += 1;,
        1 => counter += 2;,
        else => counter = 0;,
    }
}
  • Note: statement arms using expressions must end with ;. Commas between arms are optional.

2) Statement form with block bodies​

fn update(kind: u32) -> void {
    var counter: u32 = 0;
    switch (kind) {
        0 => {
            counter += 1;
        },
        1 => {
            counter += 2;
        },
        else => {
            counter = 0;
        },
    }
}

3) Range patterns (inclusive)​

fn grade(score: u32) -> u8 {
    var g: u8 = 0;
    switch (score) {
        0...59   => g = 0;,
        60...69  => g = 1;,
        70...79  => g = 2;,
        80...89  => g = 3;,
        90...100 => g = 4;,
        else     => g = 5;,
    }
    return g;
}

4) Enum variant patterns (qualified)​

enum Status : u8 { Pending, Active, Suspended, Closed }

fn describe(s: Status) -> u32 {
    switch (s) {
        Status.Pending   => 0,
        Status.Active    => 1,
        Status.Suspended => 2,
        else             => 3,
    }
}

Where to find more​

  • Semantics fixtures:
    • tests/fixtures/semantics/valid/
    • tests/fixtures/semantics/invalid/
  • Parser fixtures: tests/fixtures/parser/
  • Reference snippets: ora-example/ (some files are experimental and may not compile under the current parser)

To inspect examples quickly:

./zig-out/bin/ora lex path/to/example.ora
./zig-out/bin/ora parse path/to/example.ora
./zig-out/bin/ora -o build ast path/to/example.ora