Multistring

Introduction

multistring defines a new type, Wrap, that has the underlying type []string, with methods defined on it that correspond to¹ the free functions in the standard library's strings package. Each method performs the equivalent of applying the corresponding function over the slice, like the map higher-order function would.

Example

w := multistring.Wrap{" apple  ", "banana ", "  celery"}
s := w.TrimSpace().ToUpper().Repeat(3).JoinBy(",")

println(s)
// APPLEAPPLEAPPLE,BANANABANANABANANA,CELERYCELERYCELERY

Method signatures

The methods' signatures are derived from those of the corresponding functions, subject to two transformations:

1. The elements in the Wrap will be implicitly passed as the first string argument to the strings function
2. Every return type T will be transformed to the slice type []T, unless T is string, in which case it will be transformed to Wrap, to allow chaining.

Other methods

There are two additional methods on Wrap that are not derived from strings, JoinBy and MapString:

• JoinBy can be used for cases where, as a final step, you want to join a group of strings (contained in a Wrap) with the same separator, rather than join a group of strings (passed to the Join method) with a group of separators contained in a Wrap.
• MapString is the analogue of strings.Map, but taking a function that takes a string (func(string) string), instead of a rune.

Why did I do this?

For a side project, I needed to apply functions from strings over slices of strings. After writing a few for loops, I decided to abstract it out into what is now Wrap, and then I thought - what if I could generate these method definitions?

A couple of days later...