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Types and statements

Account parameters and the checks they emit

Every account exposes key, lamports, dataLen, isSigner, isWritable. At most 32 accounts per instruction (more is refused, 5113).

Two writable parameters can never be the same account: aliasing is refused with error 2040 (also when a remaining account written through .lamports or loadAccountMut is another account of the instruction).

Built-ins

• systemProgram.transfer(from: Mut<Signer>, to, lamports), systemProgram.createAccount(payer, account, lamports, space, owner, signerSeeds?) (the new account signs: a keypair Mut<Signer> or this program's PDA), rentExempt(space), MINT_SIZE, TOKEN_ACCOUNT_SIZE
• Token programs (TokenProgram, Token2022Program, TokenInterface) — pass signerSeeds (with the bump) when the authority is a PDA: transfer, transferChecked(from, mint, to, authority, amount) (required by Token-2022 mints with fees/hooks), mintTo, burn, closeAccount, approve(source, delegate, owner, amount), revoke, setAuthority(target, current, AuthorityType.MintTokens, next | null), freezeAccount / thawAccount(account, mint, freezeAuthority), syncNative(account), initializeMint2(mint, decimals, mintAuthority, freezeAuthority | null), initializeAccount3(account, mint, owner), and on Token-2022 initializeMetadata(mint, updateAuthority, mintAuthority, name, symbol, uri) (metadata extension)
• account.lamports read/write on Mut accounts, close(account, destination) for program accounts
• requirePda(account, seeds, bump)

Implementing another program's interface (transfer hooks)

/** @discriminator spl-transfer-hook-interface:execute */ above an instruction replaces its Anchor discriminator with sha256(preimage)[..8] (or @discriminator 0x… for raw bytes), so a TypeSOL program can be a Token-2022 transfer hook: execute(source, mint, destination, owner, extraMetas, amount) plus initExtraAccountMetas(payer, account, mint, systemProgram) for the validation account. See test/fixtures/hook.ts.

Calling other programs

export function relayIncrement(authority: Signer, counter: Mut<AccountInfo>, counterProgram: Program<"JD2v…99Y2">, by: u64): void {
  invoke(counterProgram, [readonlySigner(authority), writable(counter)], [sighash("increment"), by]);
}

// Sign for a PDA of this program: raw System transfer (u32 tag 2, u64 lamports) out of a treasury PDA.
invoke(systemProgram, [writableSigner(treasury), writable(recipient)], [u32(2n), amount], ["treasury", admin.key, bump]);

• accounts: readonly(x), writable(x), readonlySigner(x), writableSigner(x). The compiler refuses writable on a non-Mut parameter and a signer flag on an account that neither signed nor is covered by signerSeeds.
• data (Borsh): integers little-endian at their declared width (u32(2n) is 4 bytes, a bare 5n is a u64), booleans, Pubkeys, strings, Options, structs and FixedArrays (their fixed layout), data enums, Vec arguments, sighash("name") (Anchor discriminator), hex("0a0b"). Up to 1024 bytes.
• signerSeeds (with the bump) signs for this program's PDA.
• After the call, returnData<u64>(program) reads what the callee returned, checking the size and that it came from program.

Typed calls from an IDL: typesol cpi other.json --out other_cpi.ts writes one helper per instruction (vaultDeposit(program, owner, vault, systemProgram, amount, seeds)), with the account flags, discriminator and argument encoding taken from the IDL (Anchor 0.30+ / 1.x, or TypeSOL's own). Call it with signer([...seeds, bump]) when a PDA of your program signs, or signer([]). Instructions whose arguments have no Borsh-identical TypeSOL type (strings or Options inside structs, data-carrying enums) are listed and left out.

PDAs in the IDL

When an instruction calls x.create(payer, seeds) or requirePda(x, seeds, bump) and every seed is a string literal, an integer literal, an argument, acct.key or a scalar field of an account, the IDL entry for x gets Anchor pda.seeds (const / arg / account), so Anchor and Codama clients derive the address themselves.

Not supported yet

Vecs anywhere but the last account field, growing an account by more than 10 KiB in one instruction, growing a Vec inside a helper, data-enum arguments carrying strings/structs, Pubkeys in templates, ?. / ! / **, switch on 128-bit integers, mulDiv beyond u64, transfer hooks with extra accounts, Token Metadata creators/collections, Core plugins, Bubblegum v2 / collections / transfers, floating point (by design), do … while. They are rejected at compile time rather than half-supported.

Init.create handles a PDA address someone pre-funded: it tops up rent, then allocates and assigns instead of create_account (which would fail).