From 1db483f7eca72e35bd361d87de52d350fd9dfbed Mon Sep 17 00:00:00 2001
From: Joshua Reusch <jreusch4@gmail.com>
Date: Wed, 2 Oct 2024 21:55:28 +0200
Subject: [PATCH] Size, Piece custom types

---
 src/string_width.gleam       | 59 ++++++++++++++++++------------------
 test/despair_test.gleam      |  2 +-
 test/string_width_test.gleam | 14 ++++-----
 3 files changed, 38 insertions(+), 37 deletions(-)

diff --git a/src/string_width.gleam b/src/string_width.gleam
index e1471a1..d12b1be 100644
--- a/src/string_width.gleam
+++ b/src/string_width.gleam
@@ -130,6 +130,12 @@ pub fn at_tab_offset(options: Options, tab_offset: Int) -> Options {
 
 // -- MEASURING STRINGS --------------------------------------------------------
 
+/// A custom type making it easy to differentiate the width (columns) and
+/// height (rows).
+pub type Size {
+  Size(rows: Int, columns: Int)
+}
+
 /// Get the number of columns required to print a line in a terminal.
 ///
 /// If multiple lines are given, the length of the longest line is returned.
@@ -150,8 +156,8 @@ pub fn at_tab_offset(options: Options, tab_offset: Int) -> Options {
 /// // --> 5
 /// ```
 pub fn line(str: String) -> Int {
-  let #(_, cols) = dimensions_with(str, default_options)
-  cols
+  let Size(columns:, rows: _) = dimensions_with(str, default_options)
+  columns
 }
 
 /// Like `line`, but use custom options.
@@ -167,8 +173,8 @@ pub fn line(str: String) -> Int {
 /// // --> 2
 /// ```
 pub fn line_with(str: String, options: Options) -> Int {
-  let #(_, cols) = dimensions_with(str, options)
-  cols
+  let Size(columns:, rows: _) = dimensions_with(str, options)
+  columns
 }
 
 /// The required number of rows and columns to display the given text.
@@ -185,12 +191,12 @@ pub fn line_with(str: String, options: Options) -> Int {
 /// dimensions("hello,\n안녕하세요")
 /// // --> #(2, 10)
 /// ```
-pub fn dimensions(str: String) -> #(Int, Int) {
+pub fn dimensions(str: String) -> Size {
   dimensions_with(str, default_options)
 }
 
 /// Like `dimensions`, but use custom options.
-pub fn dimensions_with(str: String, options: Options) -> #(Int, Int) {
+pub fn dimensions_with(str: String, options: Options) -> Size {
   let #(str, ranges, range_width) = prepare_measure(options, str)
 
   let fun = fn(state, chr, width) {
@@ -218,9 +224,10 @@ pub fn dimensions_with(str: String, options: Options) -> #(Int, Int) {
   let #(rows, cols_max, cols_curr) =
     fold_parts(str, 0, ranges, #(0, 0, options.tab_offset), on_chars, on_range)
 
+  let columns = int.max(cols_max, cols_curr) - options.tab_offset
   case cols_curr > 0 {
-    True -> #(rows + 1, int.max(cols_max, cols_curr) - options.tab_offset)
-    False -> #(rows, cols_max - options.tab_offset)
+    True -> Size(rows: rows + 1, columns:)
+    False -> Size(rows:, columns:)
   }
 }
 
@@ -230,7 +237,7 @@ fn tab(options: Options, col: Int) -> Int {
 }
 
 // magic hook that allows us to not be stupid with FFI and still get
-// _most_ of the performance (we are now like 50% slower).
+// _most_ of the performance (we are now like 50% slower, or back to old speed).
 @external(javascript, "./string_width_ffi.mjs", "prepare_measure")
 fn prepare_measure(
   options: Options,
@@ -249,18 +256,7 @@ fn prepare_measure(
 // line to short? align left/right/center/stretch
 // line to long? truncate/wrap
 // break at? shys/whitespace/unicode word boudnaries/grahpeme boundaries? this is hard
-// widows when wrapping
-// margins
-//
-
-// if one component is followed by another zero-width component treat them as one?
-// maybe even in fold?
-// mode_ext
-// mode_wcwidth
-
-// mixed: pass grapheme clusters but measure codepoints
-// individual_codepoints (default see above) / for grapheme clusters, pass width at the first cp
-// passing codepoints is only useful for measure? I don't think a user ever wants that
+// justify vs text align
 
 // fold over words? (handle shy hyphens/soft breaks etc)
 // I do not want to implement full unicode word segmentation here though
@@ -282,6 +278,11 @@ pub fn is_ansi_component(str: String, options: Options) -> Bool {
   }
 }
 
+/// The measured pieces of a string, passed to you by `fold` and `fold_with`
+pub type Piece {
+  Piece(piece: String, row: Int, column: Int, width: Int)
+}
+
 /// A higher-level `fold` that keeps track of the position inside of the string.
 ///
 /// Handles tabs and newlines, and always passes full grapheme clusters,
@@ -291,7 +292,7 @@ pub fn is_ansi_component(str: String, options: Options) -> Bool {
 pub fn fold(
   over str: String,
   from state: state,
-  with fun: fn(state, String, Int, Int, Int) -> state,
+  with fun: fn(state, Piece) -> state,
 ) -> state {
   fold_with(str, default_options, state, fun)
 }
@@ -306,17 +307,17 @@ pub fn fold_with(
   over str: String,
   using options: Options,
   from state: state,
-  with fun: fn(state, String, Int, Int, Int) -> state,
+  with fun: fn(state, Piece) -> state,
 ) -> state {
-  let fun = fn(state, chr, width) {
-    let #(state, row, col) = state
+  let fun = fn(state, piece, width) {
+    let #(state, row, column) = state
 
-    let state = fun(state, chr, width, row, col)
+    let state = fun(state, Piece(piece:, row:, column:, width:))
 
-    case chr {
+    case piece {
       "\n" -> #(state, row + 1, options.tab_offset)
-      "\t" -> #(state, row, tab(options, col))
-      _ -> #(state, row, col + width)
+      "\t" -> #(state, row, tab(options, column))
+      _ -> #(state, row, column + width)
     }
   }
 
diff --git a/test/despair_test.gleam b/test/despair_test.gleam
index 44d3140..a10f52e 100644
--- a/test/despair_test.gleam
+++ b/test/despair_test.gleam
@@ -4,7 +4,7 @@ import string_width
 fn sw(str: String) {
   let options =
     string_width.new()
-    |> string_width.mode_2027
+    |> string_width.mode_2027_ext
 
   string_width.line_with(str, options)
 }
diff --git a/test/string_width_test.gleam b/test/string_width_test.gleam
index 689c029..9747c94 100644
--- a/test/string_width_test.gleam
+++ b/test/string_width_test.gleam
@@ -1,6 +1,6 @@
 import gleeunit
 import gleeunit/should
-import string_width.{dimensions, line as sw}
+import string_width.{Size, dimensions, line as sw}
 
 pub fn main() {
   gleeunit.main()
@@ -41,16 +41,16 @@ pub fn docs_test() {
   swg("👩‍👩‍👦‍👦") |> should.equal(2)
   sw("\u{1B}[31mhello\u{1B}[39m") |> should.equal(5)
 
-  dimensions("안녕하세요") |> should.equal(#(1, 10))
+  dimensions("안녕하세요") |> should.equal(Size(1, 10))
 
-  dimensions("hello,\n안녕하세요") |> should.equal(#(2, 10))
+  dimensions("hello,\n안녕하세요") |> should.equal(Size(2, 10))
 }
 
 pub fn dimensions_test() {
-  dimensions("") |> should.equal(#(0, 0))
-  dimensions("\n") |> should.equal(#(1, 0))
-  dimensions("\nhello") |> should.equal(#(2, 5))
-  dimensions("hello,\n안녕하세요\n") |> should.equal(#(2, 10))
+  dimensions("") |> should.equal(Size(0, 0))
+  dimensions("\n") |> should.equal(Size(1, 0))
+  dimensions("\nhello") |> should.equal(Size(2, 5))
+  dimensions("hello,\n안녕하세요\n") |> should.equal(Size(2, 10))
 }
 
 pub fn pedantic_test() {
-- 
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