This is currently a PoC for a DFA that supports submatches extraction. The match time complexity is linear in length of the text to match. Read the article if you are interested in the implementation.
nimble install nregex
Nim +1.0.4
import pkg/nregex
var m: RegexMatch
doAssert match("abc", re"abc", m)
doAssert match("ab", re"a(b|c)", m)
doAssert match("aabcd", re"(aa)bcd", m)
doAssert m.group(0) == @[0 .. 1]
doAssert match("aab", re"((a)*b)", m)
doAssert m.group(0) == @[0 .. 2]
doAssert m.group(1) == @[0 .. 0, 1 .. 1]
doAssert "abcd".find(re"bc", m)
doAssert "2222".find(re"(22)*", m)
doAssert m.group(0) == @[0 .. 1, 2 .. 3]
doAssert re"bc" in "abcd"
doAssert re"(23)+" in "112323211"The following benchmarks show nregex is up to 22 times faster than PCRE. However, when the RE contains capture groups, PCRE is about 4 times faster than nregex.
| relative | time/iter | iters/s | regex | text | |
|---|---|---|---|---|---|
| CPU | 294.85ps | 3.39G | |||
| PCRE | 1.10ms | 912.11 | ^\w*sol\w*$ | (a*100000)sol(b*100000) | |
| nregex | 739.52% | 148.25us | 6.75K | ||
| PCRE | 174.87ns | 5.72M | ^[0-9]+-[0-9]+-[0-9]+$ | 650-253-0001 | |
| nregex | 2280.84% | 7.67ns | 130.43M | ||
| PCRE | 179.23ns | 5.58M | ^[0-9]+..+$ | 650-253-0001 | |
| nregex | 1447.15% | 12.38ns | 80.74M |
nimble test
MIT