Fully refactored the code to make it more rusty!

versions before 1.3.0 were mostly a rewrite of python library in rust, but in this version I tried to make it more rusty, it still can be a lot better, but its a job for other times.
- we now store all different forms of a letter as a single character instead of old `&'static str` so thats a plus, although I used `\0` for showing empty character, we still have to see how it'll work out.
- fully changed how `letters` work.
- create a new module named `form` to store all the code related to form that is shared between different modules. we use enum now instead of const variables!
- updated ligatures.
- updated reshaper to use the new changes.
- moved test outside of crate.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ar-reshaper"
-version = "1.1.0"
+version = "1.3.0"
 authors = ["Saeid Ghafari <saeid025@yahoo.com>"]
 edition = "2021"
 description = "Reconstruct Arabic sentences to be used in applications that don't support Arabic script."

src/config.rs

@@ -1,4 +1,4 @@
-use crate::{letters::LettersType, ligatures::*, ArabicReshaper};
+use crate::{form::LettersType, ligatures::*, ArabicReshaper};
 
 /// Flags to enable some or all groups of ligatures
 #[derive(Default, Clone, Copy)]
@@ -46,6 +46,7 @@ pub enum Language {
     /// work with both unicode and classic Arabic-Kurdish keybouard
     Kurdish,
     /// Custom language
+    #[cfg_attr(feature = "serde", serde(skip))] // we can't serialize this
     Custom(&'static [LettersType]),
 }
 
@@ -61,6 +62,27 @@ impl std::fmt::Display for Language {
     }
 }
 
+/// Hold state of whatever some ligatures are enabled or not.
+#[derive(Clone)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub struct Ligatures {
+    pub(crate) vec: Vec<bool>,
+}
+
+impl Ligatures {
+    fn new(vec: Vec<bool>) -> Self {
+        Self { vec }
+    }
+
+    fn is_any_enabled(&self) -> bool {
+        self.vec.iter().any(|enabled| *enabled)
+    }
+
+    pub fn is_ligature_enabled(&self, name: LigatureNames) -> bool {
+        self.vec[name as usize]
+    }
+}
+
 /// The main Config struct for the [ArabicReshaper]
 ///
 /// You can change all kinds of settings about [ArabicReshaper] using this struct.
@@ -88,7 +110,7 @@ pub struct ReshaperConfig {
     /// Separate ligatures configuration take precedence over it.
     /// When `support_ligatures` is disabled,
     /// separate ligatures configurations are ignored.
-    pub(crate) ligatures: Vec<bool>,
+    pub ligatures: Ligatures,
 }
 
 impl Default for ReshaperConfig {
@@ -113,7 +135,7 @@ impl Default for ReshaperConfig {
             support_zwj: true,
             use_unshaped_instead_of_isolated: false,
             support_ligatures: true,
-            ligatures,
+            ligatures: Ligatures::new(ligatures),
         }
     }
 }
@@ -146,7 +168,7 @@ impl ReshaperConfig {
         Self {
             language,
             support_ligatures: !ligatures_flags.is_none_enabled(),
-            ligatures,
+            ligatures: Ligatures::new(ligatures),
             ..Default::default()
         }
     }
@@ -239,9 +261,9 @@ impl ReshaperConfig {
     }
 
     /// Update the given [LigatureNames].
-    pub fn update_ligature(&mut self, key: LigatureNames, enable: bool) {
-        self.ligatures[key as usize] = enable;
+    pub fn update_ligature(&mut self, name: LigatureNames, enable: bool) {
+        self.ligatures.vec[name as usize] = enable;
         // enable or disable ligatures if anything is enabled
-        self.support_ligatures = self.ligatures.iter().any(|enabled| *enabled);
+        self.support_ligatures = self.ligatures.is_any_enabled();
     }
 }

src/form.rs

@@ -0,0 +1,45 @@
+/// Type of letters
+pub type LettersType = (char, Forms);
+
+/// Form of the letter
+#[derive(Clone, Copy, PartialEq, Eq)]
+#[repr(usize)]
+pub(crate) enum LetterForm {
+    Isolated,
+    Initial,
+    Medial,
+    Final,
+    Unsupported,
+    Unshaped,
+}
+
+/// The main type used to show letter form in each position
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub struct Forms {
+    pub isolated: char,
+    pub initial: char,
+    pub medial: char,
+    pub end: char,
+}
+
+impl Forms {
+    pub const fn new(isolated: char, initial: char, medial: char, end: char) -> Self {
+        Self {
+            isolated,
+            initial,
+            medial,
+            end,
+        }
+    }
+
+    pub(crate) const fn get(&self, form: LetterForm) -> char {
+        match form {
+            LetterForm::Isolated => self.isolated,
+            LetterForm::Initial => self.initial,
+            LetterForm::Medial => self.medial,
+            LetterForm::Final => self.end,
+            _ => panic!("Unsupported Letter form"),
+        }
+    }
+}