OxL Reference
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kw fail

Reserved keyword

The list of words: §1.4

Syntax

ebnf
Primary     = Literal | Path | "it" | "self" | "(" Expr { "," Expr } ")" | ListLit | MapLit
            | StructLit | Lambda | Block | If | Match | For | While | Loop | Scope | Select | Query
            | "spawn" ( Postfix | Block ) | "await" Unary | "atomic" [ "(" Args ")" ] Block
            | "return" [ Expr ] | "fail" Expr | "yield" Expr | "respond" Expr | "break" [ Label ] [ Expr ]
            | "continue" [ Label ] | "emit" Path "(" Expr ")" | "unsafe" Block | "blocking" Block
            | "comptime" Block | "." Ident [ "(" [ Args ] ")" ] ;

Grammar: App. A

Defined in

  • 5.8 Other expressions — defer e — executes e on leaving the block (including on fail, return, cancellation), in the reverse order of declaration.
  • 6.5 Errors — There are no exceptions.
  • 3.1 Primitives — Integer arithmetic.
  • 8.4 Chains — A chain links asynchronous steps so that either the whole chain is executed or the first unhandled error is returned.
  • 10.3 Streams — The type is stream<T, E = never>.
  • 18.4 Simulation — In sim the scheduler, network, clocks, randomness and disk failures are deterministic; the result depends only on the seed.
  • 1.4 Keywords — Reserved (cannot be used as names)
  • 4.3 Construction and constructors — Literal. T{ f1: e1, f2, ..base }

Examples

oxl
@error data NotFound { what: str }
@error enum PayError { Declined(reason: str), Fraud }

fn charge(card: Card, sum: Money) -> Receipt | PayError | NetError  net {
  let token = Vault.tokenize(card)?          // ? propagates the errors of the call
  if sum <= Money.zero() { fail PayError.Declined("zero sum") }
  Bank.pay(token, sum)
}

— 6.5 Errors

Related diagnostics

fail-type, question-context, unhandled-error, it-outside-chain, yield-outside-stream, bad-init, missing-field, must-close, positional-literal, sealed-literal

See also