supporting ascii literals

Signed-off-by: Jakub Doka <jakub.doka2@gmail.com>

lang/README.md

@@ -121,10 +121,12 @@ main := fn(): uint {
 	decimal := 255
 	octal := 0o377
 	binary := 0b11111111
+	ascii := '\n'
 
 	if hex == decimal & octal == decimal & binary == decimal {
 		return 0
 	}
+
 	return 1
 }
 ```

lang/src/fmt.rs

@@ -314,6 +314,7 @@ impl<'a> Formatter<'a> {
             }
             Expr::Slf { .. } => f.write_str("Self"),
             Expr::String { literal, .. } => f.write_str(literal),
+            Expr::Char { literal, .. } => f.write_str(literal),
             Expr::Comment { literal, .. } => f.write_str(literal),
             Expr::Mod { path, .. } => write!(f, "@use(\"{path}\")"),
             Expr::Embed { path, .. } => write!(f, "@embed(\"{path}\")"),

lang/src/lib.rs

@@ -306,7 +306,7 @@ fn endoce_string(
     literal: &str,
     str: &mut Vec<u8>,
     report: impl Fn(&core::str::Bytes, &str),
-) -> Option<()> {
+) -> Option<usize> {
     let report = |bytes: &core::str::Bytes, msg: &_| {
         report(bytes, msg);
         None::<u8>
@@ -332,7 +332,9 @@ fn endoce_string(
     };
 
     let mut bytes = literal.bytes();
+    let mut char_len = 0;
     while let Some(b) = bytes.next() {
+        char_len += 1;
         if b != b'\\' {
             str.push(b);
             continue;
@@ -354,11 +356,7 @@ fn endoce_string(
         str.push(b);
     }
 
-    if str.last() != Some(&0) {
-        report(&bytes, "string literal must end with null byte (for now)");
-    }
-
-    Some(())
+    Some(char_len)
 }
 
 pub fn quad_sort<T>(mut slice: &mut [T], mut cmp: impl FnMut(&T, &T) -> core::cmp::Ordering) {

lang/src/parser.rs

@@ -356,6 +356,7 @@ impl<'a, 'b> Parser<'a, 'b> {
             T::Idk => E::Idk { pos },
             T::Die => E::Die { pos },
             T::DQuote => E::String { pos, literal: self.tok_str(token) },
+            T::Quote => E::Char { pos, literal: self.tok_str(token) },
             T::Packed => {
                 self.packed = true;
                 let expr = self.unit_expr()?;
@@ -896,6 +897,11 @@ generate_expr! {
             pos: Pos,
             literal: &'a str,
         },
+        /// `'\'([^']|\\\')\''`
+        Char {
+            pos: Pos,
+            literal: &'a str,
+        },
         /// `'//[^\n]' | '/*' { '([^/*]|*/)*' | Comment } '*/'
         Comment {
             pos: Pos,

lang/src/son.rs

@@ -2975,7 +2975,7 @@ impl<'a> Codegen<'a> {
             }
             Expr::Ident { id, pos, .. } => self.find_type_as_value(pos, self.ci.parent, id, ctx),
             Expr::Comment { .. } => Some(Value::VOID),
-            Expr::String { pos, literal } => {
+            Expr::Char { pos, literal } | Expr::String { pos, literal } => {
                 let literal = &literal[1..literal.len() - 1];
                 let mut data = core::mem::take(&mut self.pool.lit_buf);
                 debug_assert!(data.is_empty());
@@ -2984,7 +2984,30 @@ impl<'a> Codegen<'a> {
                     self.error(pos + (literal.len() - bytes.len()) as u32 - 1, message);
                 };
 
-                crate::endoce_string(literal, &mut data, report).unwrap();
+                let char_count = crate::endoce_string(literal, &mut data, report).unwrap();
+
+                if matches!(expr, Expr::Char { .. }) {
+                    if char_count != 1 {
+                        return self.error(
+                            pos,
+                            fa!("character literal can only contain one character, \
+                            but you supplied {char_count}"),
+                        );
+                    }
+
+                    let value = match data.as_slice() {
+                        &[v] => v as i64,
+                        _ => return self.error(pos, "TODO: support utf-8 characters"),
+                    };
+
+                    data.clear();
+                    self.pool.lit_buf = data;
+
+                    self.gen_inferred_const(ctx, ty::Id::U8, value, ty::Id::is_integer)
+                } else {
+                    if data.last() != Some(&0) {
+                        self.error(pos, "string literal must end with null byte (for now)");
+                    }
 
                     let ty = self.tys.make_ptr(ty::Id::U8);
                     let global = self
@@ -3006,6 +3029,7 @@ impl<'a> Codegen<'a> {
 
                     Some(Value::new(global).ty(ty))
                 }
+            }
             Expr::Defer { pos, value } => {
                 self.ci.defers.push((pos, ExprRef::new(value)));
                 Some(Value::VOID)