feat: basic progress bar

gleam.toml

@@ -14,6 +14,7 @@ version = "1.0.0"
 
 [dependencies]
 gleam_stdlib = ">= 0.34.0 and < 2.0.0"
+ansi = ">= 0.1.0 and < 1.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -0,0 +1,13 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "ansi", version = "0.1.0", build_tools = ["rebar3"], requirements = [], otp_app = "ansi", source = "hex", outer_checksum = "4BF92B41E29E0480350A3260DC3F7ED52073C56FE236EFCAB1680A5E4C3923A5" },
+  { name = "gleam_stdlib", version = "0.38.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "663CF11861179AF415A625307447775C09404E752FF99A24E2057C835319F1BE" },
+  { name = "gleeunit", version = "1.1.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "72CDC3D3F719478F26C4E2C5FED3E657AC81EC14A47D2D2DEBB8693CA3220C3B" },
+]
+
+[requirements]
+ansi = { version = ">= 0.1.0 and < 1.0.0"}
+gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
+gleeunit = { version = ">= 1.0.0 and < 2.0.0" }

src/glitzer.gleam

@@ -1,5 +1,26 @@
-import gleam/io
+import glitzer/progress
+
+@external(erlang, "glitzer_ffi", "sleep")
+@external(javascript, "./glitzer_ffi.mjs", "sleep")
+pub fn sleep(ms: Int) -> a
 
 pub fn main() {
-  io.println("Hello from glitzer!")
+  let bar = progress.default_bar()
+
+  do_something(bar, 0)
+}
+
+fn do_something(bar, count) {
+  case count < 100 {
+    True -> {
+      let bar = case count > 50 {
+        True -> progress.finish(bar)
+        False -> progress.tick(bar)
+      }
+      progress.print_bar(bar)
+      sleep(15)
+      do_something(bar, count + 1)
+    }
+    False -> Nil
+  }
 }

src/glitzer/codes.gleam

@@ -0,0 +1,11 @@
+/// Print this code to clear the whole screen.
+pub const clear_screen_code = "\u{001b}[2J"
+
+/// Print this code to clear the current line.
+pub const clear_line_code = "\u{001b}[2K"
+
+/// Print this code to return the cursor to the "home" position.
+pub const return_home_code = "\u{001b}[H"
+
+/// Print this code to return to the start of the line
+pub const return_line_start_code = "\r"

src/glitzer/progress.gleam

@@ -0,0 +1,191 @@
+import gleam/io
+import gleam/string
+import gleam/string_builder.{type StringBuilder}
+
+import glitzer/codes
+
+/// A `String` with only one character.
+pub opaque type Char {
+  Char(char: String)
+}
+
+/// Create a `Char` from a `String`. Returns a `Char` with the given string if
+/// the strings length is equal to one and a `Char` of "#" otherwise.
+///
+/// <details>
+/// <summary>Example:<summary>
+///
+/// ```gleam
+/// import glitzer/progress
+///
+/// fn example() {
+///   let char = progress.char_from_string("A")
+/// }
+/// ```
+pub fn char_from_string(from in: String) -> Char {
+  let len = string.length(in)
+
+  case len {
+    1 -> Char(in)
+    _ -> Char("#")
+  }
+}
+
+pub fn string_from_char(from in: Char) -> String {
+  in.char
+}
+
+pub opaque type State {
+  State(progress: Int)
+}
+
+/// The style of a progress bar.
+pub opaque type ProgressStyle {
+  ProgressStyle(
+    left: String,
+    right: String,
+    empty: Char,
+    fill: Char,
+    length: Int,
+    state: State,
+  )
+}
+
+/// Create and return a default style for a progress bar.
+pub fn default_bar() -> ProgressStyle {
+  ProgressStyle(
+    left: "[",
+    right: "]",
+    empty: Char(" "),
+    fill: Char("#"),
+    length: 100,
+    state: State(progress: 0),
+  )
+}
+
+/// Create a new (completely empty) progress bar.
+///
+/// <details>
+/// <summary>Example:<summary>
+///
+/// ```gleam
+/// import glitzer/progress
+///
+/// fn example() {
+///   let bar = 
+///     progress.new_bar()
+///     |> progress.with_length(50)
+///     |> progress.with_left_text("Progress: ")
+///     |> progress.with_fill(progress.char_from_string("+"))
+/// }
+/// ```
+pub fn new_bar() -> ProgressStyle {
+  ProgressStyle(
+    left: "",
+    right: "",
+    empty: Char(" "),
+    fill: Char(" "),
+    length: 0,
+    state: State(progress: 0),
+  )
+}
+
+/// Add left text to a progress bar.
+pub fn with_left_text(
+  bar bar: ProgressStyle,
+  left text: String,
+) -> ProgressStyle {
+  ProgressStyle(..bar, left: text)
+}
+
+/// Add right text to a progress bar.
+pub fn with_right_text(
+  bar bar: ProgressStyle,
+  right text: String,
+) -> ProgressStyle {
+  ProgressStyle(..bar, right: text)
+}
+
+/// Add a character to a progress bar that is used to represent the
+/// "background" of the bar.
+pub fn with_empty(bar bar: ProgressStyle, empty char: Char) -> ProgressStyle {
+  ProgressStyle(..bar, empty: char)
+}
+
+/// Add a character to a progress bar that is used to fill the bar on each
+/// tick.
+pub fn with_fill(bar bar: ProgressStyle, fill char: Char) -> ProgressStyle {
+  ProgressStyle(..bar, fill: char)
+}
+
+/// Add length to a progress bar.
+pub fn with_length(bar bar: ProgressStyle, length len: Int) -> ProgressStyle {
+  ProgressStyle(..bar, length: len)
+}
+
+/// Increase the progress of the bar by one.
+pub fn tick(bar bar: ProgressStyle) -> ProgressStyle {
+  ProgressStyle(..bar, state: State(progress: bar.state.progress + 1))
+}
+
+/// Completely fill the progress bar.
+pub fn finish(bar bar: ProgressStyle) -> ProgressStyle {
+  ProgressStyle(..bar, state: State(progress: bar.length + 1))
+}
+
+/// Print the progress bar to stderr.
+///
+/// <details>
+/// <summary>Example:<summary>
+///
+/// ```gleam
+/// import glitzer/progress
+///
+/// fn example() {
+///   let bar = progress.default_bar()
+///
+///   run_example(bar, 0)
+/// }
+///
+/// fn run_example(bar, count) {
+///   case count < 100 {
+///     True -> {
+///       let bar = progress.tick(bar)
+///       // do some awesome stuff :3
+///       progress.print_bar(bar)
+///       run_example(bar, count + 1)
+///     }
+///     False -> Nil
+///   }
+/// }
+/// ```
+pub fn print_bar(bar bar: ProgressStyle) {
+  let fill =
+    build_progress_fill(string_builder.new(), bar, bar.state.progress, 0)
+    |> string_builder.to_string
+
+  io.print_error(
+    codes.clear_line_code
+    <> codes.return_line_start_code
+    <> bar.left
+    <> fill
+    <> bar.right,
+  )
+}
+
+fn build_progress_fill(
+  fill: StringBuilder,
+  bar: ProgressStyle,
+  left_nonempty: Int,
+  count: Int,
+) -> StringBuilder {
+  let fill = case left_nonempty > 0 {
+    True -> string_builder.append(fill, bar.fill.char)
+    False -> string_builder.append(fill, bar.empty.char)
+  }
+
+  case bar.length > count {
+    True -> build_progress_fill(fill, bar, left_nonempty - 1, count + 1)
+    False -> fill
+  }
+}

src/glitzer_ffi.erl

@@ -0,0 +1,7 @@
+-module(glitzer_ffi).
+
+% Public API
+-export([sleep/1]).
+
+sleep(Int) ->
+  timer:sleep(Int).

src/glitzer_ffi.mjs

@@ -0,0 +1,3 @@
+export function sleep(ms = 0) {
+  return new Promise(resolve => setTimeout(resolve, ms));
+}