Merge pull request #693 from matthiasbeyer/libimagutil/result-extension-cleanup

Libimagutil/result extension cleanup (documentation)
This commit is contained in:
Matthias Beyer 2016-09-05 17:46:19 +02:00 committed by GitHub
commit 47389f0f24
4 changed files with 57 additions and 2 deletions

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@ -1,3 +1,5 @@
// Generates a extension for the `Result<T, E>`, named `DebugResult` which has functionality to
// print either `T` or `E` via `debug!()`.
generate_result_logging_extension!(
DebugResult,
map_dbg,

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@ -1,3 +1,5 @@
// Generates a extension for the `Result<T, E>`, named `DebugResult` which has functionality to
// print either `T` or `E` via `info!()`.
generate_result_logging_extension!(
InfoResult,
map_info,

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@ -1,3 +1,52 @@
/// This macro is used to generate extensions for the `Result<T, U>` type which only have
/// sideeffects.
///
/// This macro is then used to generate debug/info/log/warning/etc extensions.
///
/// It is exported, so other crates can use it to generate more specific extensions for
/// `Result<T, U>` types
///
/// # Parameters
///
/// The documentation for the parameters of the macro follow.
///
/// ## `$name`
///
/// name of the trait to generate
///
/// ## `$map_name`
///
/// Name of the function which is generated to call the closure with.
///
/// This function gets `&T` from `Result<T, E>` and can now build the argument for
/// `$closure`. So, this function can, for example, `|e| format!("Look here: {:?}", e)`, the
/// result gets fed to `$closure`.
///
/// ## `$map_str_name`
///
/// Name of the function which is generated to call the closure with.
///
/// This function gets simply a `&str` which gets fed to the `$closure` later.
/// So it can be used to `foo().$map_str_name("Something happened")`
///
/// ## `$map_err_name`
///
/// Same as `$map_name`, but gets `&E` from `Resul<T, E>`.
///
/// ## `$map_err_str_name`
///
/// Same as `$map_str_name`, but is called for error cases in `Result<T, E>` (though no
/// argument is passed.
///
/// ## `$closure`
///
/// The closure which should be called when mapping.
///
/// This closure can now do things, but the return value of the closure is discarded.
/// So, this closure can be used for its sideeffects (logging for example) only.
///
/// An example would be: `|element| debug!("Element: {:?}", element)`.
///
#[macro_export]
macro_rules! generate_result_logging_extension {
{
@ -8,7 +57,7 @@ macro_rules! generate_result_logging_extension {
$map_err_str_name: ident,
$closure: expr
} => {
pub trait InfoResult<T, E> : Sized {
pub trait $name<T, E> : Sized {
fn $map_name<F: FnOnce(&T) -> String>(self, f: F) -> Self;
@ -24,7 +73,7 @@ macro_rules! generate_result_logging_extension {
}
impl<T, E> InfoResult<T, E> for Result<T, E> {
impl<T, E> $name<T, E> for Result<T, E> {
fn $map_name<F: FnOnce(&T) -> String>(self, f: F) -> Self {
self.map(|x| { $closure(f(&x)); x })

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@ -1,3 +1,5 @@
// Generates a extension for the `Result<T, E>`, named `DebugResult` which has functionality to
// print either `T` or `E` via `warn!()`.
generate_result_logging_extension!(
WarnResult,
map_warn,