Quick Reference

Functions

The functions provided fall into a few main types:

Input functions convert values into result types
Output functions convert result types back into values
Transform functions operate on result types
Predicate functions return booleans
Collection functions provide an interface to access collections without exceptions.

Works on	Function	Description
Result	`to_result`	Convert nullable to `Result`
Option	`to_option`	Convert nullable to `Option`

Works on	Function	Description
Both	`unwrap`	Return inner value or throw an error
Both	`unwrap_or`	Return inner value or default value
Both	`to_nullable`	Convert `Result`/`Option` into a nullable value

Works on	Function	Description
Result	`ok`	Convert `Result` to `Option`
Option	`ok_or`	Convert `Option` to `Result`
Both	`try_map`	Map a function over one or more result values
Result	`map_err`	Map a function over an error value
Both	`and_then`	Chain fallable functions together
Both	`try_collect`	Collect an iterable of results into a result containing an array
Option	`try_collect_option`	Version of `try_collect` specialized for `Option`. Unexported.
Result	`try_collect_result`	Version of `try_collect` specialized for `Result`. Unexported.
Both	`flatten`	Flatten a nested result type

Works on	Function	Description
Result	`is_ok`	Return if a `Result` is `Ok`
Result	`is_err`	Return if a `Result` is `Err`
Option	`is_some`	Return if an `Option` is `Some`.
Option	`is_none`	Return if an `Option` is `None`
Both	`has_val`	Return if a result type is a success.

Works on	Function	Description
Option	`try_pop!`	Try to `pop!` a value from a collection. Also works with `Iterators.Stateful`.
Option	`try_get`	Try to `get` a value from a collection
Option	`try_peek`	Try to `peek` a value from an iterator
Option	`try_first`	Try to get the first value in a collection
Option	`try_last`	Try to get the last value in a collection

Macro	Description
`@unwrap_or`	Short-circuiting version of `unwrap_or`, which allows for the embedding of control statements.
`@try_unwrap`	Unwraps a value or bubbles an error upstream.
`@some_if`	Evaluates and returns `Some` if a predicate is satisfied
`@catch_result`	Catch an exception and return it as a `Result` instead
`@if_let`	Conditionally unwrap a value inside of a block
`@while_let`	Run a loop while successful

The following operators are overloaded for use with Result types:

Operator	Description
`Base.:&`	And/all operator, returns the first `Err` value. Supports closures for lazy evaluation.
`Base.:\|`	Or/any operator, returns the first `Ok` value. Supports closures for lazy evaluation.
`Base.:!`	Flips Ok and Error values, turning `Result{T, E}` into `Result{E, T}`.

In addition, three new operators are introduced for use with Results and Options:

Operator	Description
`←`	`try_map`: applies a function to the inside of a result type.
`→`	Argument-flipped version of `try_map`.
`⊗`	`and_then`/monadic bind: connects fallable functions together and returns errors early.

These new operators are not exported by default.