refactor(parser): rename vars (#4565)

Use `b` everywhere in lexer for a `u8` byte, keeping the name `c` for a vars containing a `char`.

crates/oxc_parser/src/lexer/kind.rs

@@ -206,12 +206,12 @@ impl Kind {
         )
     }
 
-    pub fn matches_number_char(self, c: u8) -> bool {
+    pub fn matches_number_char(self, b: u8) -> bool {
         match self {
-            Decimal => c.is_ascii_digit(),
-            Binary => matches!(c, b'0'..=b'1'),
-            Octal => matches!(c, b'0'..=b'7'),
-            Hex => c.is_ascii_hexdigit(),
+            Decimal => b.is_ascii_digit(),
+            Binary => matches!(b, b'0'..=b'1'),
+            Octal => matches!(b, b'0'..=b'7'),
+            Hex => b.is_ascii_hexdigit(),
             _ => unreachable!(),
         }
     }

crates/oxc_parser/src/lexer/number.rs

@@ -49,14 +49,14 @@ pub fn parse_float(s: &str, has_sep: bool) -> Result<f64, &'static str> {
 
 /// b'0' is 0x30 and b'9' is 0x39.
 ///
-/// So we can convert from any decimal digit to its value with `c & 15`.
-/// This is produces more compact assembly than `c - b'0'`.
+/// So we can convert from any decimal digit to its value with `b & 15`.
+/// This is produces more compact assembly than `b - b'0'`.
 ///
 /// <https://godbolt.org/z/WMarz15sq>
 #[inline]
-const fn decimal_byte_to_value(c: u8) -> u8 {
-    debug_assert!(c >= b'0' && c <= b'9');
-    c & 15
+const fn decimal_byte_to_value(b: u8) -> u8 {
+    debug_assert!(b >= b'0' && b <= b'9');
+    b & 15
 }
 
 #[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
@@ -71,15 +71,15 @@ fn parse_decimal(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
+    for b in s.as_bytes() {
         // The latency of the multiplication can be hidden by issuing it
         // before the result is needed to improve performance on
         // modern out-of-order CPU as multiplication here is slower
         // than the other instructions, we can get the end result faster
         // doing multiplication first and let the CPU spends other cycles
         // doing other computation and get multiplication result later.
         result *= 10;
-        let n = decimal_byte_to_value(*c);
+        let n = decimal_byte_to_value(*b);
         result += n as u64;
     }
     result as f64
@@ -97,10 +97,10 @@ fn parse_decimal_with_underscores(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
+    for b in s.as_bytes() {
+        if *b != b'_' {
             result *= 10;
-            let n = decimal_byte_to_value(*c);
+            let n = decimal_byte_to_value(*b);
             result += n as u64;
         }
     }
@@ -121,14 +121,14 @@ fn parse_decimal_slow(s: &str) -> f64 {
 
 /// b'0' is 0x30 and b'1' is 0x31.
 ///
-/// So we can convert from binary digit to its value with `c & 1`.
-/// This is produces more compact assembly than `c - b'0'`.
+/// So we can convert from binary digit to its value with `b & 1`.
+/// This is produces more compact assembly than `b - b'0'`.
 ///
 /// <https://godbolt.org/z/1vvrK78jf>
 #[inline]
-const fn binary_byte_to_value(c: u8) -> u8 {
-    debug_assert!(c == b'0' || c == b'1');
-    c & 1
+const fn binary_byte_to_value(b: u8) -> u8 {
+    debug_assert!(b == b'0' || b == b'1');
+    b & 1
 }
 
 /// NOTE: bit shifting here is is safe and much faster than f64::mul_add.
@@ -159,9 +159,9 @@ fn parse_binary(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
+    for b in s.as_bytes() {
         result <<= 1;
-        result |= binary_byte_to_value(*c) as u64;
+        result |= binary_byte_to_value(*b) as u64;
     }
     result as f64
 }
@@ -170,8 +170,8 @@ fn parse_binary(s: &str) -> f64 {
 #[inline(never)]
 fn parse_binary_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        let value = f64::from(binary_byte_to_value(*c));
+    for b in s.as_bytes() {
+        let value = f64::from(binary_byte_to_value(*b));
         result = result.mul_add(2.0, value);
     }
     result
@@ -191,10 +191,10 @@ fn parse_binary_with_underscores(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
+    for b in s.as_bytes() {
+        if *b != b'_' {
             result <<= 1;
-            result |= binary_byte_to_value(*c) as u64;
+            result |= binary_byte_to_value(*b) as u64;
         }
     }
     result as f64
@@ -204,9 +204,9 @@ fn parse_binary_with_underscores(s: &str) -> f64 {
 #[inline(never)]
 fn parse_binary_with_underscores_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
-            let value = f64::from(binary_byte_to_value(*c));
+    for b in s.as_bytes() {
+        if *b != b'_' {
+            let value = f64::from(binary_byte_to_value(*b));
             result = result.mul_add(2.0, value);
         }
     }
@@ -217,14 +217,14 @@ fn parse_binary_with_underscores_slow(s: &str) -> f64 {
 
 /// b'0' is 0x30 and b'7' is 0x37.
 ///
-/// So we can convert from any octal digit to its value with `c & 7`.
-/// This is produces more compact assembly than `c - b'0'`.
+/// So we can convert from any octal digit to its value with `b & 7`.
+/// This is produces more compact assembly than `b - b'0'`.
 ///
 /// <https://godbolt.org/z/9rYTsMoMM>
 #[inline]
-const fn octal_byte_to_value(c: u8) -> u8 {
-    debug_assert!(c >= b'0' && c <= b'7');
-    c & 7
+const fn octal_byte_to_value(b: u8) -> u8 {
+    debug_assert!(b >= b'0' && b <= b'7');
+    b & 7
 }
 
 #[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
@@ -239,8 +239,8 @@ fn parse_octal(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        let n = octal_byte_to_value(*c);
+    for b in s.as_bytes() {
+        let n = octal_byte_to_value(*b);
         result <<= 3;
         result |= n as u64;
     }
@@ -252,8 +252,8 @@ fn parse_octal(s: &str) -> f64 {
 #[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
 fn parse_octal_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        let value = f64::from(octal_byte_to_value(*c));
+    for b in s.as_bytes() {
+        let value = f64::from(octal_byte_to_value(*b));
         result = result.mul_add(8.0, value);
     }
     result
@@ -271,9 +271,9 @@ fn parse_octal_with_underscores(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
-            let n = octal_byte_to_value(*c);
+    for b in s.as_bytes() {
+        if *b != b'_' {
+            let n = octal_byte_to_value(*b);
             result <<= 3;
             result |= n as u64;
         }
@@ -286,9 +286,9 @@ fn parse_octal_with_underscores(s: &str) -> f64 {
 #[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
 fn parse_octal_with_underscores_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
-            let value = f64::from(octal_byte_to_value(*c));
+    for b in s.as_bytes() {
+        if *b != b'_' {
+            let value = f64::from(octal_byte_to_value(*b));
             result = result.mul_add(8.0, value);
         }
     }
@@ -301,22 +301,22 @@ fn parse_octal_with_underscores_slow(s: &str) -> f64 {
 /// - b'A' is 0x41 and b'F' is 0x46.
 /// - b'a' is 0x61 and b'f' is 0x66.
 ///
-/// So we can convert from a digit to its value with `c & 15`,
-/// and from `A-F` or `a-f` to its value with `(c & 15) + 9`.
-/// We could use `(c & 7) + 9` for `A-F`, but we use `(c & 15) + 9`
-/// so that both branches share the same `c & 15` operation.
+/// So we can convert from a digit to its value with `b & 15`,
+/// and from `A-F` or `a-f` to its value with `(b & 15) + 9`.
+/// We could use `(b & 7) + 9` for `A-F`, but we use `(b & 15) + 9`
+/// so that both branches share the same `b & 15` operation.
 ///
 /// This is produces more slightly more assembly than explicitly matching all possibilities,
 /// but only because compiler unrolls the loop.
 ///
 /// <https://godbolt.org/z/5fsdv8rGo>
 #[inline]
-const fn hex_byte_to_value(c: u8) -> u8 {
-    debug_assert!((c >= b'0' && c <= b'9') || (c >= b'A' && c <= b'F') || (c >= b'a' && c <= b'f'));
-    if c < b'A' {
-        c & 15 // 0-9
+const fn hex_byte_to_value(b: u8) -> u8 {
+    debug_assert!((b >= b'0' && b <= b'9') || (b >= b'A' && b <= b'F') || (b >= b'a' && b <= b'f'));
+    if b < b'A' {
+        b & 15 // 0-9
     } else {
-        (c & 15) + 9 // A-F or a-f
+        (b & 15) + 9 // A-F or a-f
     }
 }
 
@@ -333,8 +333,8 @@ fn parse_hex(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        let n = hex_byte_to_value(*c);
+    for b in s.as_bytes() {
+        let n = hex_byte_to_value(*b);
         result <<= 4;
         result |= n as u64;
     }
@@ -345,8 +345,8 @@ fn parse_hex(s: &str) -> f64 {
 #[inline(never)]
 fn parse_hex_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        let value = f64::from(hex_byte_to_value(*c));
+    for b in s.as_bytes() {
+        let value = f64::from(hex_byte_to_value(*b));
         result = result.mul_add(16.0, value);
     }
     result
@@ -365,9 +365,9 @@ fn parse_hex_with_underscores(s: &str) -> f64 {
     }
 
     let mut result = 0_u64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
-            let n = hex_byte_to_value(*c);
+    for b in s.as_bytes() {
+        if *b != b'_' {
+            let n = hex_byte_to_value(*b);
             result <<= 4;
             result |= n as u64;
         }
@@ -379,9 +379,9 @@ fn parse_hex_with_underscores(s: &str) -> f64 {
 #[inline(never)]
 fn parse_hex_with_underscores_slow(s: &str) -> f64 {
     let mut result = 0_f64;
-    for c in s.as_bytes() {
-        if *c != b'_' {
-            let value = f64::from(hex_byte_to_value(*c));
+    for b in s.as_bytes() {
+        if *b != b'_' {
+            let value = f64::from(hex_byte_to_value(*b));
             result = result.mul_add(16.0, value);
         }
     }

crates/oxc_parser/src/lexer/numeric.rs

@@ -42,30 +42,30 @@ impl<'a> Lexer<'a> {
     fn read_non_decimal(&mut self, kind: Kind) -> Kind {
         self.consume_char();
 
-        if self.peek_byte().is_some_and(|c| kind.matches_number_char(c)) {
+        if self.peek_byte().is_some_and(|b| kind.matches_number_char(b)) {
             self.consume_char();
         } else {
             self.unexpected_err();
             return Kind::Undetermined;
         }
 
-        while let Some(c) = self.peek_byte() {
-            match c {
+        while let Some(b) = self.peek_byte() {
+            match b {
                 b'_' => {
                     self.consume_char();
                     // NOTE: it looks invalid numeric tokens are still parsed.
                     // This seems to be a waste. It also requires us to put this
                     // call here instead of after we ensure the next character
                     // is a number character
                     self.token.set_has_separator();
-                    if self.peek_byte().is_some_and(|c| kind.matches_number_char(c)) {
+                    if self.peek_byte().is_some_and(|b| kind.matches_number_char(b)) {
                         self.consume_char();
                     } else {
                         self.unexpected_err();
                         return Kind::Undetermined;
                     }
                 }
-                c if kind.matches_number_char(c) => {
+                b if kind.matches_number_char(b) => {
                     self.consume_char();
                 }
                 _ => break,

crates/oxc_parser/src/lexer/regex.rs

@@ -58,16 +58,16 @@ impl<'a> Lexer<'a> {
         let pattern_end = self.offset() - 1; // -1 to exclude `/`
         let mut flags = RegExpFlags::empty();
 
-        while let Some(ch @ (b'$' | b'_' | b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9')) =
+        while let Some(b @ (b'$' | b'_' | b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9')) =
             self.peek_byte()
         {
             self.consume_char();
-            let Ok(flag) = RegExpFlags::try_from(ch) else {
-                self.error(diagnostics::reg_exp_flag(ch as char, self.current_offset()));
+            let Ok(flag) = RegExpFlags::try_from(b) else {
+                self.error(diagnostics::reg_exp_flag(b as char, self.current_offset()));
                 continue;
             };
             if flags.contains(flag) {
-                self.error(diagnostics::reg_exp_flag_twice(ch as char, self.current_offset()));
+                self.error(diagnostics::reg_exp_flag_twice(b as char, self.current_offset()));
                 continue;
             }
             flags |= flag;

crates/oxc_parser/src/lexer/unicode.rs

@@ -161,9 +161,9 @@ impl<'a> Lexer<'a> {
 
     fn hex_digit(&mut self) -> Option<u32> {
         let value = match self.peek_byte() {
-            Some(c @ b'0'..=b'9') => u32::from(c) - '0' as u32,
-            Some(c @ b'a'..=b'f') => 10 + (u32::from(c) - 'a' as u32),
-            Some(c @ b'A'..=b'F') => 10 + (u32::from(c) - 'A' as u32),
+            Some(b @ b'0'..=b'9') => u32::from(b) - '0' as u32,
+            Some(b @ b'a'..=b'f') => 10 + (u32::from(b) - 'a' as u32),
+            Some(b @ b'A'..=b'F') => 10 + (u32::from(b) - 'A' as u32),
             _ => return None,
         };
         self.consume_char();