bettys-bike-shop

bettys-bike-shop/README.md

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+# Betty's Bike Shop
+
+Welcome to Betty's Bike Shop on Exercism's Gleam Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
+
+## Introduction
+
+## Ints
+
+There are two different kinds of numbers in Gleam - ints and floats.
+
+Ints are whole numbers.
+
+```gleam
+let integer = 3
+// -> 3
+```
+
+Gleam has several operators that work with ints.
+
+```gleam
+1 + 1 // -> 2
+5 - 1 // -> 4
+5 / 2 // -> 2
+3 * 3 // -> 9
+5 % 2 // -> 1
+
+2 > 1  // -> True
+2 < 1  // -> False
+2 >= 1 // -> True
+2 <= 1 // -> False
+```
+
+## Floats
+
+Floats are numbers with one or more digits behind the decimal separator.
+
+```gleam
+let float = 3.45
+// -> 3.45
+```
+
+Floats also have their own set of operators.
+
+```gleam
+1.0 +. 1.4 // -> 2.4
+5.0 -. 1.5 // -> 3.5
+5.0 /. 2.0 // -> 2.5
+3.0 *. 3.1 // -> 9.3
+
+2.0 >. 1.0  // -> True
+2.0 <. 1.0  // -> False
+2.0 >=. 1.0 // -> True
+2.0 <=. 1.0 // -> False
+```
+
+## Modules
+
+### Modules
+
+Gleam code is organised into modules, and each file is one Gleam module.
+
+Up until now we have written functions with the `pub fn` syntax, which defines a function that is publicly available to other modules. Functions defined with `fn` are private to the module they are defined in and cannot be used by other modules.
+
+```gleam
+// This function is public
+pub fn add(x, y) {
+  x + y
+}
+
+// This function is private
+fn subtract(x, y) {
+  x - y
+}
+```
+
+Gleam modules have names, and the name is based on their file path within the `src` or `test` directory.
+
+For example, a module defined in `src\geometry\rectangle.gleam` (on Windows) or `src/geometry/rectangle.gleam` (on UNIX-like operating systems) would be named `geometry/rectangle`.
+
+### Importing functions from other modules
+
+Accessing functions defined in other modules is done via imports.
+All functions within that module that were exposed by it are made accessible when importing that module.
+But how they are accessed varies depending on how the module is imported.
+
+Qualified imports are the default, and accessing a function within such module (for example the `map` function in the `gleam/list` module) is done by prefixing the module name (`list.map`).
+
+```gleam
+// Import the int module
+import gleam/int
+
+pub fn run(x: Int) -> String {
+  // Use the to_string function from the int module
+  int.to_string(x)
+}
+```
+
+By default the name used to refer to the module is the last part of the module name, in this case `int`, but this can be changed by using the `as` keyword.
+
+```gleam
+// Import the int module and refer to it as i
+import gleam/int as i
+
+pub fn run(x: Int) -> String {
+  i.to_string(x)
+}
+```
+
+Unqualified imports enable direct access to the exposed functions within that module, without prefixing.
+
+```gleam
+// Import the to_string function from the int module
+import gleam/int.{to_string}
+
+pub fn run(x: Int) -> String {
+  to_string(x)
+}
+```
+
+Qualified imports are preferred as they make it clearer to the reader where a function comes from, and to avoid name clashes.
+
+
+### Standard library
+
+Gleam has a rich and well-documented standard library. The documentation is available online at [hexdocs.pm/gleam_stdlib][docs]. Save this link somewhere - you will use it a lot!
+
+Most built-in data types have a corresponding module that offers functions for working with that data type, e.g. there's the `gleam/int` module for ints, `gleam/string` module for strings, `gleam/list` module for lists and so on.
+
+[docs]: https://hexdocs.pm/gleam_stdlib/
+
+## Instructions
+
+In this exercise you're going to write some code to help Betty's Bike Shop, an online shop for bikes and parts.
+You have three tasks, aiming at correctly displaying the bikes and parts prices on the website.
+
+## 1. Export the `pence_to_pounds` function
+
+Your colleague has already written the skeleton of the module, the incomplete functions `pence_to_pounds` and `pounds_to_string`.
+However, they have forgotten to export the `pence_to_pounds` function, so it is currently not visible by other modules or by the test suite.
+
+Export the `pence_to_pounds` function.
+
+## 2. Convert pence to pounds
+
+Currently, the price is stored as an integer number of *pence* (the bike shop is based in the UK).
+On the website, we want to show the price in *pounds*, where 1.00 pound amounts to 100 pence.
+Your first task is to implement the `pence_to_pounds` function, taking an `Int` amount of pence, and converting it into its equivalent pounds as a `Float`.
+You should also add type annotations for that function.
+
+```gleam
+pence_to_pounds(106)
+// -> 1.06
+```
+
+## 3. Format the price for display on the website
+
+Since Betty's bikes are sold in pounds, prices should be displayed with the symbol "£".
+Your second task is thus to implement the `pounds_to_string` function, taking an amount of pounds as a `Float` and returning its price displayed as a `String` with the pound symbol prepended.
+
+You should import the `gleam/float` and `gleam/string` modules before using them.
+
+You should also define the type annotation for `pounds_to_string`.
+
+```gleam
+pounds_to_string(1.06)
+// -> "£1.06"
+```
+
+## Source
+
+### Created by
+
+- @lpil