stdlib

Description

A function to pad a string with zeros or another symbol to a given width could be helpful in many cases, especially together with the to_string() function for integer to string conversion.

Currently available methods to achieve this are using concatenation

width = 32
str = "hello"
padded_str = repeat('0',width-len(str)')//str

and perhaps also internal file I/O

import gleeunit
import gleam/bit_builder

pub fn main() {
  gleeunit.main()
}

pub fn bit_string_size_test() {
  <<1:int-size(1)>>
  |> bit_builder.from_bit_string()
  |> bit_builder.byte_size()
}

crashes with

λ ~/bitstringsize/ master* gleam test
  Compiling gleam_stdlib
  Compiling gleeunit
  Compiling bitstringsize
   Compiled in 1.41s
    Running bitstrings

We would need a symmetrical operation to product from Applicative but for Monad (or Bind) backed by a let-operator: val (and*) : 'a t -> 'b t -> ('a * 'b) t.