Returns `true` when the text is a numeric literal (integer or float, including hex `0x`, octal `0o`, binary `0b`, and underscored forms).
(t: &str)
| 68 | /// Returns `true` when the text is a numeric literal (integer or float, |
| 69 | /// including hex `0x`, octal `0o`, binary `0b`, and underscored forms). |
| 70 | fn is_numeric_literal(t: &str) -> bool { |
| 71 | if t.is_empty() { |
| 72 | return false; |
| 73 | } |
| 74 | |
| 75 | let bytes = t.as_bytes(); |
| 76 | |
| 77 | // Hex: 0x1F, 0X1f |
| 78 | if bytes.len() >= 3 |
| 79 | && bytes[0] == b'0' |
| 80 | && (bytes[1] == b'x' || bytes[1] == b'X') |
| 81 | && bytes[2..] |
| 82 | .iter() |
| 83 | .all(|b| b.is_ascii_hexdigit() || *b == b'_') |
| 84 | { |
| 85 | return true; |
| 86 | } |
| 87 | |
| 88 | // Binary: 0b101 |
| 89 | if bytes.len() >= 3 |
| 90 | && bytes[0] == b'0' |
| 91 | && (bytes[1] == b'b' || bytes[1] == b'B') |
| 92 | && bytes[2..] |
| 93 | .iter() |
| 94 | .all(|b| *b == b'0' || *b == b'1' || *b == b'_') |
| 95 | { |
| 96 | return true; |
| 97 | } |
| 98 | |
| 99 | // Octal: 0o77 |
| 100 | if bytes.len() >= 3 |
| 101 | && bytes[0] == b'0' |
| 102 | && (bytes[1] == b'o' || bytes[1] == b'O') |
| 103 | && bytes[2..] |
| 104 | .iter() |
| 105 | .all(|b| (b'0'..=b'7').contains(b) || *b == b'_') |
| 106 | { |
| 107 | return true; |
| 108 | } |
| 109 | |
| 110 | // Decimal integer or float |
| 111 | let mut saw_dot = false; |
| 112 | let mut saw_e = false; |
| 113 | for (i, &b) in bytes.iter().enumerate() { |
| 114 | match b { |
| 115 | b'0'..=b'9' | b'_' => {} |
| 116 | b'.' if !saw_dot && !saw_e => saw_dot = true, |
| 117 | b'e' | b'E' if !saw_e && i > 0 => { |
| 118 | saw_e = true; |
| 119 | // Allow optional +/- after exponent |
| 120 | if i + 1 < bytes.len() && (bytes[i + 1] == b'+' || bytes[i + 1] == b'-') { |
| 121 | // Skip the sign — it will be consumed next iteration. |
| 122 | // We need a slightly different approach: just validate |
| 123 | // the whole thing. |
| 124 | return validate_float_suffix(&bytes[i + 1..]); |
| 125 | } |
| 126 | } |
| 127 | _ => return false, |
no test coverage detected