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Types

Pebble supports a few built-in types.

Each of these builtin types maps directly a corresponding UPLC type under the hood.

Primitives​

Pebble provides four primitive types that map directly to Plutus Core:

  • int
  • bool
  • bytes
  • string

These types form the foundation for all Pebble contracts.

int​

Arbitrary-precision signed integer.
Backed by Plutus Integer.

Example​

const supply: int = 1_000_000;
let spent: int = 500;

assert (supply - spent) >= 0;

Operators​

  • Arithmetic: +, -, *, /, %
  • Comparison: <, <=, >, >=, ==, !=

bytes​

Raw byte arrays. Commonly used for hashes, policy IDs, token names, and low-level identifiers.

Example​

const policy: bytes = #deadbeef;
const token: bytes = "MyToken".toBytes();

assert tx.outputs[0].value.amountOf(policy, token) > 0;

Pebble represents token names as bytes const token: bytes = "MyToken".toBytes(). This ensures compatibility with Plutus, where token names are byte arrays.

Common Operators​

  • Equality: ==, !=
  • Concatenation: a + b
  • Conversion: "hello".toBytes()
  • Hashing: hash(bytesVal)

string​

UTF-8 encoded text. Primarily for logging and off-chain metadata. Avoid storing large strings on-chain due to cost.

Example​

const msg: string = "Order filled";
trace(msg);

bool​

Logical true/false values. Derived from comparisons or logical expressions.

Example​

const signed: bool = tx.signatories.includes(ownerHash);

if (signed && tx.outputs.length() > 0) {
    trace("Valid transaction");
} else {
    fail "Unauthorized";
}

Operators​

  • Logical: &&, ||, !
  • Comparisons return bool

Cardano-Specific​

See Types for all cardano-specific types supported in Pebble.

Refer stdScope.ts for details regarding their definition.

Optional / Sum Types​

Option<T>​

Use Option<T> to represent values that may or may not exist.

Example​

const maybeDatum: Option<int> = Some{ value: 10 };

case/match used for destructuring​

match maybeDatum {
    Some{ value }: trace(value),
    None{}       : fail "missing datum"
}

Destructuring -

const InlineDatum{ datum: { owner, token, minAmount } as Order } = spendingInput.datum;

Structs​

Defined using struct declarations.

struct defines custom composite type with named fields.

struct Order {
    ownerPaymentCreds: Credential,
    policy: bytes,
    tokenName: bytes,
    minReceiveAmount: int
}