iterutil

Overview ¶

Package iterutil provides a set of iterutil for various data structures.

Elements of slices as pointers ¶

The main motivation is making it easier to work with slices of large structures, where people often choose an iterator pattern, which makes a shallow copy of each struct in the slice:

var myStructs []MyStruct
for _, myStruct := range myStructs {
	// myStruct is a shallow *COPY* of each element - any changes in the loop have no effect on the slice element.
}

In order to improve that, and also not have to use the throw-away `_` variable, SlicePointerValues may be used to iterate across pointers to each element in the slice:

var myStructs []MyStruct
for myStructPtr := range iterutil.SlicePointerValues(myStructs) {
	// myStructPtr is a pointer to each element - any changes in the loop will be reflected in the slice element.
}

If you still need the index, you can use SlicePointers:

var myStructs []MyStruct
for i, myStructPtr := range iterutil.SlicePointers(myStructs) {
	// myStructPtr is a pointer to each element - any changes in the loop will be reflected in the slice element.
	// i is the index of the element.
}

Walking json ¶

The https://github.com/tidwall/gjson library is already included as a dependency. If you need to walk a json document, the WalkGjsonLeaves iterator is available, which will yield the json paths to all leaves in the document along with the gjson.Result for each leaf.