Elm:
Finding the length of a string

How to:

In Elm, you use String.length to find out how many characters a string contains. Witness:

import Html exposing (text)

main =
  text (String.fromInt (String.length "Hello, Elm!"))
  -- Output: "11"

Deep Dive

Historically, string length functions have been crucial for memory management and text processing in languages with low-level access to data. Elm, being high level, abstracts these details, offering built-in functionality with String.length.

Two points worth noting:

1. Elm strings are UTF-16 encoded. String.length returns the number of UTF-16 code units, which can differ from the actual number of Unicode graphemes (user-perceived characters) in strings with complex characters.
2. There aren’t built-in alternatives to String.length in Elm. If you need the number of graphemes, you might need a custom function that accounts for Unicode intricacies.

Internally, String.length iterates over the string data structure, counting elements. As a pure function, its output depends solely on input, maintaining Elm’s functional programming ethos.

See Also

• Elm’s official String documentation: https://package.elm-lang.org/packages/elm/core/latest/String#length
• UTF-16: https://en.wikipedia.org/wiki/UTF-16