gassert is Go package that provides function like assert of Python or C++.
With gassert, you can check validation of parameters or values more easily and cleaner.
Since Golang don't provide assert function by default, if you want to check validation of params, you should write like below.
func MyFunc(n int, s string, arr []string, p *MyStruct) {
if n == 0 || len(s) == 0 || arr == nil || p == nil {
// error
}
}With gassert, you can write that:
func MyFunc(n int, s string, arr []string, p *MyStruct) {
// raise panic if any of them has zero-value
gassert.Zeros(n, s, arr, p)
}And you can check other conditions besides zero-value.
func MyFunc(n int, s string, arr []string, p *MyStruct) {
gassert.NumLess(n, 100)
gassert.StrLenGreater(s, 10)
gassert.SliceLenEquals(arr, 0)
gassert.Zeros(p)
}If you want to check multiple condition on one line, you can write below:
func MyFunc(n int, s string, arr []string, p *MyStruct) {
// raise panic if any of conditions is true
gassert.New().NumLess(n, 5).StrLenGreater(s, 10).SliceLenEquals(arr, 0).Zeros(0).Panic()
if err := gassert.New().NumLess(n, 5).StrLenGreater(s, 10).SliceLenEquals(arr, 0).Zeros(0).Err(); err != nil {
// handle error
}
}When you write like this, SHOULD start with New() and end with Panic() , PanicDetails(), Err(), ErrDetails.
-
Panic(): raise panic if any of condition is true -
PanicDetail(): raise panic if any of condition is true with information -
Err(): returnerrorif any of condition is true -
ErrDetails(): returnerrorif any of condition is true with information
There is difference from general comparison statement in number. In Go, you can compare in only same types.
But gassert compares its values no matter what types. For example, you can write this:
func MyFunc(n int) {
gassert.NumLess(n, 12.34)
}It may lose type-safety, but i thougth it is better idea for convenience.
gassert is thread-safety because it makes internal event object every calls. And the object is managed by sync.Pool, so it is economical in memory usage.
If you want to check complex condition which doesn't exists in gassert. You can just use Go().
func MyFunc(n int, s string) {
gassert.Go((n-5) % 10 == 10 || len(s)*2 > 10)
}