--- name: compact-core:standard-library description: Use when importing from CompactStandardLibrary, working with crypto functions (persistentHash, persistentCommit, ecAdd, ecMul), utility types (Maybe, Either), token operations (mintToken, send, receive, mergeCoin), or time functions (blockTime, blockTimeBefore, blockTimeAfter). --- # Compact Standard Library Complete reference for `CompactStandardLibrary` - the built-in module providing cryptographic functions, utility types, token operations, and time functions. ## Import ```compact import { persistentHash, Maybe, mintToken, blockTime } from "CompactStandardLibrary"; ``` ## Quick Reference ### Cryptographic Functions | Function | Safe? | Purpose | |----------|-------|---------| | `persistentCommit(value)` | Yes | Create hiding commitment with nonce (cross-transaction stable) | | `transientCommit(value)` | Yes | Create hiding commitment with nonce (transaction-local) | | `persistentHash(domain, value)` | No | Domain-separated hash (cross-transaction stable) | | `transientHash(domain, value)` | No | Domain-separated hash (transaction-local) | | `ecAdd(p1, p2)` | - | Elliptic curve point addition | | `ecMul(scalar, point)` | - | Elliptic curve scalar multiplication | **Safe vs Unsafe**: Commit functions include a random nonce, making them hiding. Hash functions do not include a nonce - if the input has low entropy, the hash can be brute-forced. ### Utility Types | Type | Purpose | Variants | |------|---------|----------| | `Maybe` | Optional value | `Some(T)`, `None` | | `Either` | Result/choice | `Left(L)`, `Right(R)` | ### Token Operations | Function | Purpose | |----------|---------| | `mintToken(info)` | Create new tokens | | `send(coin, recipient)` | Send tokens to address | | `receive()` | Receive tokens in circuit | | `mergeCoin(coins)` | Combine multiple coins | ### Time Functions | Function | Purpose | |----------|---------| | `blockTime()` | Current block timestamp | | `blockTimeBefore(time)` | Assert current time < time | | `blockTimeAfter(time)` | Assert current time > time | ## Common Patterns ### Safe Commitment ```compact import { persistentCommit } from "CompactStandardLibrary"; witness get_secret(): Field; export circuit commit_secret(): Bytes<32> { const secret = get_secret(); // Safe: commitment hides the secret return persistentCommit(secret); } ``` ### Nullifier Generation ```compact import { persistentHash } from "CompactStandardLibrary"; witness get_secret(): Field; export circuit generate_nullifier(): Bytes<32> { const secret = get_secret(); // Unsafe but intentional: nullifier should be deterministic return persistentHash("nullifier", secret); } ``` ### Optional Value Handling ```compact import { Maybe } from "CompactStandardLibrary"; ledger values: Map, Field>; export circuit get_or_default(key: Bytes<32>): Field { const result = values.lookup(key); return if result is Maybe::Some(v) { v } else { 0 }; } ``` ### Time-Locked Action ```compact import { blockTime, blockTimeAfter } from "CompactStandardLibrary"; ledger unlock_time: Cell>; export circuit withdraw(): [] { // Fails if current block time <= unlock_time blockTimeAfter(unlock_time.read()); // Perform withdrawal... } ``` ## References - [Crypto Functions](./references/crypto-functions.md) - Hash, commit, EC operations - [Utility Types](./references/utility-types.md) - Maybe, Either patterns - [Token Operations](./references/token-operations.md) - mintToken, send, receive, mergeCoin - [Time Functions](./references/time-functions.md) - blockTime and time constraints ## Examples - [Crypto Patterns](./examples/crypto-patterns.compact) - Cryptographic function usage - [Token Contract](./examples/token-contract.compact) - Token operations example - [Time-Locked](./examples/time-locked.compact) - Time-based logic example

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