Add json string parsing

[johnynek]

close #433

[johnynek]

benchmark of this code:

[info] Benchmark                          (test)  Mode  Cnt      Score      Error  Units
[info] BarBench.catsParseParse               N/A  avgt    5     ≈ 10⁻⁴             ms/op
[info] BarBench.fastparseParse               N/A  avgt    5     ≈ 10⁻⁴             ms/op
[info] BarBench.jawnParse                    N/A  avgt    5     ≈ 10⁻⁴             ms/op
[info] BarBench.parboiled2Parse              N/A  avgt    5     ≈ 10⁻⁴             ms/op
[info] BarBench.parsleyParseCold             N/A  avgt    5      0.062 ±    0.001  ms/op
[info] Bla25Bench.catsParseParse             N/A  avgt    5     42.636 ±    0.282  ms/op
[info] Bla25Bench.fastparseParse             N/A  avgt    5     15.629 ±    0.143  ms/op
[info] Bla25Bench.jawnParse                  N/A  avgt    5      7.452 ±    0.043  ms/op
[info] Bla25Bench.parboiled2Parse            N/A  avgt    5     16.390 ±    0.087  ms/op
[info] Bla25Bench.parsleyParseCold           N/A  avgt    5     30.787 ±    0.158  ms/op
[info] CountriesBench.catsParseParse         N/A  avgt    5      9.264 ±    0.033  ms/op
[info] CountriesBench.fastparseParse         N/A  avgt    5      5.052 ±    0.025  ms/op
[info] CountriesBench.jawnParse              N/A  avgt    5      1.257 ±    0.008  ms/op
[info] CountriesBench.parboiled2Parse        N/A  avgt    5      2.773 ±    0.012  ms/op
[info] CountriesBench.parsleyParseCold       N/A  avgt    5     11.621 ±    0.392  ms/op
[info] Qux2Bench.catsParseParse              N/A  avgt    5     11.809 ±    0.049  ms/op
[info] Qux2Bench.fastparseParse              N/A  avgt    5      6.461 ±    0.047  ms/op
[info] Qux2Bench.jawnParse                   N/A  avgt    5      2.176 ±    0.006  ms/op
[info] Qux2Bench.parboiled2Parse             N/A  avgt    5      5.452 ±    0.006  ms/op
[info] Qux2Bench.parsleyParseCold            N/A  avgt    5     10.108 ±    0.189  ms/op
[info] StringInBenchmarks.linearMatchIn      foo  avgt    5     78.571 ±    0.797  ns/op
[info] StringInBenchmarks.linearMatchIn    broad  avgt    5  93375.006 ± 3022.573  ns/op
[info] StringInBenchmarks.oneOfParse         foo  avgt    5     94.752 ±    0.751  ns/op
[info] StringInBenchmarks.oneOfParse       broad  avgt    5   1095.949 ±   25.393  ns/op
[info] StringInBenchmarks.radixMatchIn       foo  avgt    5     59.749 ±    0.037  ns/op
[info] StringInBenchmarks.radixMatchIn     broad  avgt    5    742.420 ±    0.113  ns/op
[info] StringInBenchmarks.stringInSParse     foo  avgt    5     94.084 ±    0.254  ns/op
[info] StringInBenchmarks.stringInSParse   broad  avgt    5   1004.531 ±    1.304  ns/op
[info] StringInBenchmarks.stringInVParse     foo  avgt    5     97.028 ±   13.912  ns/op
[info] StringInBenchmarks.stringInVParse   broad  avgt    5   1082.276 ±    1.764  ns/op
[info] Ugh10kBench.catsParseParse            N/A  avgt    5     83.426 ±    0.073  ms/op
[info] Ugh10kBench.fastparseParse            N/A  avgt    5     45.765 ±    0.156  ms/op
[info] Ugh10kBench.jawnParse                 N/A  avgt    5     11.227 ±    0.049  ms/op
[info] Ugh10kBench.parboiled2Parse           N/A  avgt    5     27.397 ±    0.086  ms/op
[info] Ugh10kBench.parsleyParseCold          N/A  avgt    5     76.632 ±    0.270  ms/op

[johnynek]

seems like the performance of the json benchmark is rather worse with this version of the parser. A big change with using a charIn to check for valid json characters rather just anyChar, which I guess may be the problem. I'll see if I can get it back to where it was before.

[codecov-commenter]

Codecov Report

Merging #438 (3948f44) into main (d7ed829) will increase coverage by 0.13%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #438      +/-   ##
==========================================
+ Coverage   94.98%   95.12%   +0.13%     
==========================================
  Files           9       10       +1     
  Lines        1436     1476      +40     
  Branches      324      327       +3     
==========================================
+ Hits         1364     1404      +40     
  Misses         72       72              

Impacted Files	Coverage Δ
...hared/src/main/scala/cats/parse/strings/Json.scala	100.00% <100.00%> (ø)
...shared/src/main/scala/cats/parse/Accumulator.scala	97.56% <0.00%> (-2.44%)	:arrow_down:
core/shared/src/main/scala/cats/parse/Parser.scala	94.49% <0.00%> (+0.08%)	:arrow_up:

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[johnynek]

@regadas this is ready if you would have time to review.

I will post updated benchmarks but it is basically as fast as the previous benchmarks (but should be faster for escaped strings, but the benchmark doesn't stress those now).

The nice thing is that users of the library can now very easily make a quick and dirty json parser since the hard parts (numbers and strings) are provided here.

[johnynek]

No problem! Thanks for taking the time to review.