(https://github.com/ruby/strscan/pull/106) It supports non-head match cases such as StringScanner#scan_until. If we use a String as a pattern, we can improve match performance. Here is a result of the including benchmark. ## CRuby It shows String as a pattern is 1.18x faster than Regexp as a pattern. ``` $ benchmark-driver benchmark/check_until.yaml Warming up -------------------------------------- regexp 9.403M i/s - 9.548M times in 1.015459s (106.35ns/i) regexp_var 9.162M i/s - 9.248M times in 1.009479s (109.15ns/i) string 8.966M i/s - 9.274M times in 1.034343s (111.54ns/i) string_var 11.051M i/s - 11.190M times in 1.012538s (90.49ns/i) Calculating ------------------------------------- regexp 10.319M i/s - 28.209M times in 2.733707s (96.91ns/i) regexp_var 10.032M i/s - 27.485M times in 2.739807s (99.68ns/i) string 9.681M i/s - 26.897M times in 2.778397s (103.30ns/i) string_var 12.162M i/s - 33.154M times in 2.726046s (82.22ns/i) Comparison: string_var: 12161920.6 i/s regexp: 10318949.7 i/s - 1.18x slower regexp_var: 10031617.6 i/s - 1.21x slower string: 9680843.7 i/s - 1.26x slower ``` ## JRuby It shows String as a pattern is 2.11x faster than Regexp as a pattern. ``` $ benchmark-driver benchmark/check_until.yaml Warming up -------------------------------------- regexp 7.591M i/s - 7.544M times in 0.993780s (131.74ns/i) regexp_var 6.143M i/s - 6.125M times in 0.997038s (162.77ns/i) string 14.135M i/s - 14.079M times in 0.996067s (70.75ns/i) string_var 14.079M i/s - 14.057M times in 0.998420s (71.03ns/i) Calculating ------------------------------------- regexp 9.409M i/s - 22.773M times in 2.420268s (106.28ns/i) regexp_var 10.116M i/s - 18.430M times in 1.821820s (98.85ns/i) string 21.389M i/s - 42.404M times in 1.982519s (46.75ns/i) string_var 20.897M i/s - 42.237M times in 2.021187s (47.85ns/i) Comparison: string: 21389191.1 i/s string_var: 20897327.5 i/s - 1.02x slower regexp_var: 10116464.7 i/s - 2.11x slower regexp: 9409222.3 i/s - 2.27x slower ``` See: https://github.com/jruby/jruby/blob/be7815ec02356a58891c8727bb448f0c6a826d96/core/src/main/java/org/jruby/util/StringSupport.java#L1706-L1736 --------- https://github.com/ruby/strscan/commit/f9d96c446a Co-authored-by: Sutou Kouhei <[email protected]>