Mostly a documentation update

README.md

@@ -2,6 +2,9 @@
 [Universally Unique Lexicographically Sortable Identifier](https://github.com/ulid/spec) implementation in
 Gleam.
 
+What's a ULID? Some say it's a better UUID. In a string form it is shorter (26
+characters vs. 32) and sortable.
+
 # Caveats
 1. Only Erlang build target is supported (at the moment)
 
@@ -16,14 +19,14 @@ gleam add gulid
 
 ```gleam
 import gulid.{ new_as_string, new, new_monotonic, from_string_function,
-                    to_string_function }
+               to_string_function }
 
 pub fn main() {
-  // Quick and dirty ULID string - has performance implications
+  // Quick and dirty ULID string - performance implications
   let ulid_str = new_as_string()
   io.println("ULID is " <> ulid_str)
 
-  // Conver many ULIDs to String with a generator function
+  // Convert many ULIDs to String with a generator function
   let to_string = to_string_function()
   // `to_string_function` returns a function that then can be used to
   // convert `Ulid` values to `String`. The reason this is done this way is
@@ -58,11 +61,11 @@ pub fn main() {
   // Monotonic ULIDs:
   // 1. Generate initial `Ulid` with `new()`
   // 2. Then use `new_monotonic(Ulid)` with initial and subsequently generated
-  list.range(0, 9)
+  list.range(0, 9) // We want 10 monotonic ULIDs
   |> list.scan(new(), fn(ulid, _) { new_monotonic(ulid) })
+  // Convert'em to strings
   |> list.map(to_string_function())
   |> io.debug
-
 }
 ```
 # Advanced Use
@@ -103,7 +106,7 @@ pub fn main() {
 }
 
 @external(erlang, "calendar", "system_time_to_rfc3339")
-fn system_time_to_rfc3339(timestamp_millis_since_epoch: Int) -> List(Int)
+fn system_time_to_rfc3339(seconds_since_epoch: Int) -> List(Int)
 
 fn from_codepoints(code_points: List(Int)) -> String {
   code_points
@@ -118,10 +121,16 @@ fn from_codepoints(code_points: List(Int)) -> String {
 
 Further documentation can be found at <https://hexdocs.pm/gulid>.
 
-## Development
+## Examples
 
 ```sh
 gleam run -m examples/example1   # Run the example one
 gleam run -m examples/example2   # Run the example two
+```
+
+## Development
+
+```sh
 gleam test  # Run the tests
 ```
+

gleam.toml

@@ -1,15 +1,11 @@
 name = "gulid"
-version = "0.0.1"
+version = "0.0.2"
 
-# Fill out these fields if you intend to generate HTML documentation or publish
-# your project to the Hex package manager.
-#
 description = "ULID implementation in Gleam (Erlang target only)"
 licences = ["Apache-2.0"]
 repository = { type = "github", user = "vtomilin", repo = "gulid" }
-# links = [{ title = "Website", href = "" }]
 internal_modules = [
-"gulid/examples/*",
+"examples/*",
 ]
 
 [dependencies]

src/examples/example1.gleam

@@ -2,24 +2,24 @@ import gleam/io
 import gleam/list
 import gulid.{
   DecodeError, InvalidLength, from_string_function, new, new_as_string,
-  to_string_function,
+  new_monotonic, to_string_function,
 }
 
 pub fn main() {
-  // Quick and dirty ULID string - has performance implications
+  // Quick and dirty ULID string - performance implications
   let ulid_str = new_as_string()
   io.println("ULID is " <> ulid_str)
 
-  // Generate many ULIDs with a generator function
+  // Convert many ULIDs with a generator function
   let to_string = to_string_function()
   // `to_string_function` returns a function that then can be used to
   // convert `Ulid` values to `String`. The reason this is done this way is
   // that Gleam doesn't have a way to define module scoped global constants
-  // that could use function calls to initialize. Nor does it have module scoped
-  // `let`. Therefore, the only way to have a `private` reused value is to 
-  // have it as a capture. So, there is a `let` in `to_string_function`, which
-  // binds an Erlang array with ULID character encodings, captured in returned
-  // function. 
+  // that could allow function calls to initialize. Nor does it allow module 
+  // scoped `let`. Therefore, the only way to have a `private` reused immutable
+  // value is to have it as a capture in a lamdba function. So, there is a 
+  // `let` in `to_string_function`, which binds an Erlang array with ULID 
+  // character encodings, captured in the returned function. 
   let bunch_of_ulids = list.map([new(), new(), new(), new(), new()], to_string)
   io.println("A bunch of ULIDs:")
   io.debug(bunch_of_ulids)
@@ -39,6 +39,17 @@ pub fn main() {
       Nil
     }
     Error(InvalidLength(error)) | Error(DecodeError(error)) ->
-      io.println("Oh, noes: " <> error)
+      io.println("Oh, noes, the error: " <> error)
   }
+
+  // Monotonic ULIDs:
+  io.println("Generating 10 monotonic ULIDs")
+  // 1. Generate initial `Ulid` with `new()`
+  // 2. Then use `new_monotonic(Ulid)` with initial and subsequently generated
+  list.range(0, 9)
+  // We want 10 monotonic ULIDs
+  |> list.scan(new(), fn(ulid, _) { new_monotonic(ulid) })
+  // Convert'em to strings
+  |> list.map(to_string_function())
+  |> io.debug
 }

src/examples/example2.gleam

@@ -5,15 +5,16 @@ import gleam/io
 import gleam/list
 import gleam/result
 import gleam/string
-import gulid.{from_parts, from_tuple, to_parts}
+import gulid.{from_parts, from_tuple, to_parts, to_string_function}
 
 pub fn main() {
+  let to_string = to_string_function()
   let ulid =
     from_parts(
       erlang.system_time(erlang.Millisecond),
       int.random(99_999_999_999),
     )
-  io.println("My ulid made from spare parts:")
+  io.println("My ulid made from spare parts: " <> to_string(ulid))
   io.debug(ulid)
 
   let #(timestamp, random) = to_parts(ulid)
@@ -22,16 +23,19 @@ pub fn main() {
     "\tTime: "
     <> { system_time_to_rfc3339(timestamp / 1000) |> from_codepoints },
   )
-  // io.debug(system_time_to_rfc3339(timestamp / 1000))
   io.println("\tRandom: " <> int.to_string(random))
 
   let same_ulid = from_tuple(#(timestamp, random))
+  io.println(
+    "Now, we reconstruct a new ULID back from the earlier extracted components: "
+    <> to_string(same_ulid),
+  )
 
   io.println("Same ulids? " <> { bool.to_string(same_ulid == ulid) })
 }
 
 @external(erlang, "calendar", "system_time_to_rfc3339")
-fn system_time_to_rfc3339(timestamp_millis_since_epoch: Int) -> List(Int)
+fn system_time_to_rfc3339(seconds_since_epoch: Int) -> List(Int)
 
 fn from_codepoints(code_points: List(Int)) -> String {
   code_points

src/gulid.gleam

@@ -1,3 +1,23 @@
+//// ## ULID Implementation in Gleam
+////
+//// ### Create
+//// - `new()`: Non-monotonic.
+//// - `new_monotonic(Ulid)`: Monotonic using previous `Ulid` value
+//// - Parse ULID from a string:
+//// ```gleam
+//// let from_string = from_string_function()
+//// from_string(new()) |> io.debug
+//// ```
+//// - `from_parts(Int, Int)`: Create from a timestamp milliseconds from Epoch
+////                           and random.
+////
+//// ### Convert to `String`
+//// ```gleam
+////    let to_string = to_string_function()
+////    let ulid = new()
+////    io.println("Ulid: " <> to_string(ulid))
+//// ```
+
 import gleam/bit_array
 import gleam/crypto
 import gleam/dict
@@ -8,31 +28,17 @@ import gleam/order
 import gleam/result
 import gleam/string
 
-/// Represents an opaque `Ulid` type.
-///
-/// ## Create
-/// - `new()`: Non-monotonic.
-/// - `new_monotonic(Ulid)`: Monotonic using previous.
-/// - `from_string(String)`: Parse ULID from a string.
-/// - `from_parts(Int, Int)`: Create from a timestamp milliseconds from Epoch
-///                           and random.
-///
-/// ## Convert to `String`
-/// ```gleam
-///    let to_string = to_string_function()
-///    let ulid = new()
-///    io.println("Ulid: " <> to_string(ulid))
-/// ```
+/// Opaque `Ulid` type.
 pub opaque type Ulid {
   /// Create `Ulid` value from a raw `BitArray`
   Ulid(BitArray)
 }
 
-/// Ulid module errors
+/// Ulid module errors to be returned in a `Result`
 pub type UlidError {
-  /// Returned when failed to decode
+  /// Returned when failed to decode `Ulid` from a `String`
   DecodeError(mesage: String)
-  /// Returned when input is of incorrect length
+  /// Returned when input string is of incorrect length
   InvalidLength(message: String)
 }
 
@@ -67,14 +73,14 @@ pub fn to_string_function() -> fn(Ulid) -> String {
 pub fn new() -> Ulid {
   let time = erlang.system_time(erlang.Millisecond)
   let randomness = crypto.strong_random_bytes(10)
-
   Ulid(<<time:big-48, randomness:bits>>)
 }
 
-/// Returns new `Ulid` value based on given previous according to behavior,
-/// described on ULID spec, basically, if previous has the same timestamp then
-/// increment least significant bit of its random by 1 with carry to produce a
-/// new `Ulid` (with the same timestamp).
+/// Returns a new `Ulid` value based on given previous one according to the 
+/// behavior, described in the ULID spec, but basically, if the previous `Ulid`
+/// has the same timestamp then increment the least significant bit of its 
+/// random value by 1 (with carry) to produce a new `Ulid` (with the same 
+/// timestamp).
 pub fn new_monotonic(prev_ulid: Ulid) -> Ulid {
   let time = erlang.system_time(erlang.Millisecond)
   let assert Ulid(<<prev_time:unsigned-48, random:unsigned-80>>) = prev_ulid
@@ -84,8 +90,8 @@ pub fn new_monotonic(prev_ulid: Ulid) -> Ulid {
   }
 }
 
-/// Returns a non-monotonic ULID value as string. Note, this is a shortcut, 
-/// not very good as far as the performance.
+/// Returns a non-monotonic ULID value as a string. Note, this is a shortcut, 
+/// not very good for performance.
 pub fn new_as_string() -> String {
   new() |> to_string_function()
 }
@@ -216,23 +222,21 @@ pub fn from_string_function() -> fn(String) -> Result(Ulid, UlidError) {
   }
 }
 
-/// Returns an `Ulid` components `#(timestamp: Int, random: Int)` tuple.
+/// Returns `Ulid` components in a `#(timestamp, random)` tuple.
 pub fn to_parts(ulid: Ulid) -> #(Int, Int) {
-  // let assert <<timestamp:unsigned-48, random:unsigned-80>> =
-  // bit_array.append(ulid.timestamp, ulid.random)
   let assert Ulid(<<timestamp:unsigned-48, random:unsigned-80>>) = ulid
   #(timestamp, random)
 }
 
-/// Returns `Ulid` value, build from given integer timestamp (millis from Epoch)
-/// and random values
-pub fn from_parts(timestamp: Int, random: Int) -> Ulid {
+/// Returns a `Ulid` value, build from a given integer timestamp (millis from
+/// Epoch) and random values
+pub fn from_parts(timestamp timestamp: Int, random random: Int) -> Ulid {
   Ulid(<<timestamp:big-48, random:big-80>>)
 }
 
-/// Returns `Ulid` value, build from given (timestamp, random) tuple.
+/// Returns a `Ulid` value, built from a given `#(timestamp, random)` tuple.
 pub fn from_tuple(parts: #(Int, Int)) -> Ulid {
-  from_parts(parts.0, parts.1)
+  from_parts(timestamp: parts.0, random: parts.1)
 }
 
 //-- Private stuff