| Version: | 1.0.0 |
|---|---|
| Author: | luxick <op@luxick.de> |
OP stands for "Operation Result".
This module contains a generic type that can be used as a return type for operations that could fail. It adds additional messages to the result.
This module improves upon the options module in that additional messages can be passed along with the presence or absence of a value.
Basic Usage
proc divide(a, b: int): OP[float] = ## This could fail if b == 0: return fail "Cannot divide by zero!" else: return ok a / b # Wrap the result let r = divide(42, 0) assert r.isOk == false assert r.error == "Cannot divide by zero!"
Types
OP[T] = object case isOk*: bool of true: val*: T of false: error*: string
-
Object to wrap the result of an operation.
The type is discriminated by the isOK bool. So it is an compiler error to try to access the value without checking if the operation was successful.
- isOk: Indicates if the operation was successful
- val: If successful, this will hold the real result value
- error: Otherwise this will hold an error message
Procs
proc ok[T](val: T): OP[T] {...}{.inline.}
- Wraps the given value in a successful operation result.
proc fail(op: OP; msg: string): OP {...}{.inline.}
-
Will create a new operation result with the given error message. The type for the operation result is taken from the op argument.
Examples:
proc someProc(): OP[int] = result.fail "Not implemented!" let data = someProc() assert data.isOk == false assert data.error == "Not implemented!"
proc fail(T: typedesc; msg: string): OP[T] {...}{.inline.}
-
Will create a new operation result with the given error message. The type for the operation result is given explicitly.
See Also: