Documentation
¶
Overview ¶
A Try/Handle/Catch error handling mechanism implemented using generics, which provides an API similar to previous error handling proposals for the language such as https://github.com/golang/go/issues/32437.
In contrast to previous proposals, however, this implementation makes uses of calls to panic() to handle errors, rather than implicit function returns, since the latter requires language changes. This has performance implications in error cases, so it is not recommended to for use in situations where a high frequency of error returns are expected, but rather for exceptional cases. Fortunately, this is still likely to cover the majority of situations.
This package is intended to be imported unqualified, e.g.
import . "github.com/robdavid/genutil-go/errors/handler"
There are three main functions: Try(), Catch() and Handle(). Try can be used to remove the error component from a function where the function returns a value and an error, e.g.
f := Try(os.Open(fname))
If the error non-nil, the function panics, with a value of a particular type (TryError), which wraps the error. The error can recovered via the Catch() or Handle() functions.
Index ¶
- func Catch(retErr *error)
- func Check(err error)
- func Handle(handler func(err error))
- func Must[T any](t T, err error) T
- func PackageName() string
- func Raise(err error)
- func Try[T any](t T, err error) T
- func Try0(err error)
- func Try1[T any](t T, err error) T
- func Try2[T1 any, T2 any](p1 T1, p2 T2, err error) (T1, T2)
- func Try3[T1 any, T2 any, T3 any](p1 T1, p2 T2, p3 T3, err error) (T1, T2, T3)
- func Try4[T1 any, T2 any, T3 any, T4 any](p1 T1, p2 T2, p3 T3, p4 T4, err error) (T1, T2, T3, T4)
- func Try5[T1 any, T2 any, T3 any, T4 any, T5 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, err error) (T1, T2, T3, T4, T5)
- func Try6[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, err error) (T1, T2, T3, T4, T5, T6)
- func Try7[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any, T7 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, p7 T7, err error) (T1, T2, T3, T4, T5, T6, T7)
- func Try8[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any, T7 any, T8 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, p7 T7, p8 T8, err error) (T1, T2, T3, T4, T5, T6, T7, T8)
- func Try9[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any, T7 any, T8 any, T9 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, p7 T7, p8 T8, p9 T9, err error) (T1, T2, T3, T4, T5, T6, T7, T8, T9)
- type TryError
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Catch ¶
func Catch(retErr *error)
A function that will recover a panic created by Try. This should be called in a defer statement prior to calls to Try. The parameter should be a pointer to the calling function's error return value which will be set to the error intercepted by Try.
e.g.
func readFileTest(fname string) (content []byte, err error) {
defer Catch(&err)
f := Try(os.Open(fname))
defer f.Close()
content = Try(io.ReadAll(f))
return
}
func Handle ¶
func Handle(handler func(err error))
A function that will recover a panic created by Try. This should be called in a defer statement prior to calls to Try. The handler parameter is an error handling function that can be used to place error handling in one place in your function, such as wrapping the error in another error type. e.g.
func readFileWrapErr(fname string) (content []byte, err error) {
defer Handle(func(e error) {
err = fmt.Errorf("Error reading %s: %w", fname, e)
})
content = Try(os.ReadFile(fname))
return
}
func Must ¶
Must removes the error value from a return value. Panics if err is non-nil, otherwise returns the value e.g.
f := Must(os.Open("myfile"))
func PackageName ¶ added in v0.17.1
func PackageName() string
PackageName returns the pull path of this package
func Raise ¶ added in v0.15.0
func Raise(err error)
Raise an error. No-op if err is nil. An alias for Try0.
func Try ¶
Removes the error component of a function's return value. If there is no error, the non-error value is returned. Otherwise the function panics with a TryError value, wrapping the error. The panic and the error can be recovered via Catch or Handle functions. e.g.
f := Try(os.Open("myfile"))
func Try0 ¶
func Try0(err error)
Zero argument variant of Try (for functions that return an error value only)
func Try5 ¶
func Try5[T1 any, T2 any, T3 any, T4 any, T5 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, err error) (T1, T2, T3, T4, T5)
Variant of try with 5 non-error arguments
func Try6 ¶
func Try6[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, err error) (T1, T2, T3, T4, T5, T6)
Variant of try with 6 non-error arguments
func Try7 ¶
func Try7[T1 any, T2 any, T3 any, T4 any, T5 any, T6 any, T7 any](p1 T1, p2 T2, p3 T3, p4 T4, p5 T5, p6 T6, p7 T7, err error) (T1, T2, T3, T4, T5, T6, T7)
Variant of try with 7 non-error arguments
Source Files