Current File : //usr/share/doc/re2c/examples/rust/submatch/03_posix.re
// re2rust $INPUT -o $OUTPUT
// Maximum number of capturing groups among all rules.
/*!maxnmatch:re2c*/
#[derive(Debug, PartialEq)]
struct SemVer(u32, u32, u32); // version: (major, minor, patch)
fn s2n(str: &[u8]) -> u32 { // convert a pre-parsed string to a number
let mut n = 0;
for i in str { n = n * 10 + *i as u32 - 48; }
return n;
}
fn parse(str: &[u8]) -> Option<SemVer> {
let (mut cur, mut mar) = (0, 0);
// Allocate memory for capturing parentheses (twice the number of groups).
let yynmatch: usize;
let mut yypmatch = [0; YYMAXNMATCH*2];
// Autogenerated tag variables used by the lexer to track tag values.
const NONE: usize = std::usize::MAX;
/*!stags:re2c format = 'let mut @@{tag} = NONE;'; */
/*!re2c
re2c:define:YYCTYPE = u8;
re2c:define:YYPEEK = "*str.get_unchecked(cur)";
re2c:define:YYSKIP = "cur += 1;";
re2c:define:YYBACKUP = "mar = cur;";
re2c:define:YYRESTORE = "cur = mar;";
re2c:define:YYSTAGP = "@@{tag} = cur;";
re2c:define:YYSTAGN = "@@{tag} = NONE;";
re2c:define:YYSHIFTSTAG = "@@{tag} -= -@@{shift}isize as usize;";
re2c:yyfill:enable = 0;
re2c:posix-captures = 1;
num = [0-9]+;
(num) "." (num) ("." num)? [\x00] {
// `yynmatch` is the number of capturing groups
assert_eq!(yynmatch, 4);
// Even `yypmatch` values are for opening parentheses, odd values
// are for closing parentheses, the first group is the whole match.
let major = s2n(&str[yypmatch[2]..yypmatch[3]]);
let minor = s2n(&str[yypmatch[4]..yypmatch[5]]);
let patch = if yypmatch[6] == NONE {0}
else {s2n(&str[yypmatch[6] + 1..yypmatch[7]])};
return Some(SemVer(major, minor, patch));
}
* { return None; }
*/
}
fn main() {
assert_eq!(parse(b"23.34\0"), Some(SemVer(23, 34, 0)));
assert_eq!(parse(b"1.2.99999\0"), Some(SemVer(1, 2, 99999)));
assert_eq!(parse(b"1.a\0"), None);
}
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