Fix escaping for closing angle brackets.

peteruhnak commented 4 years ago

This reintroduces closing angle bracket escaping as discussed in https://github.com/antlr/stringtemplate4/issues/198 .

Note that this applies only to STGroup, not ST -- same way it was in 4.0.4 and prior.

parrt commented 4 years ago

Hi. Can you sign contributors.txt too?

peteruhnak commented 4 years ago

Hi. Can you sign contributors.txt too?

done

I've realized that the previous \>> case was a subset of the new one so I merged them.

This looks like it could have poor performance if s is very long.

I've also changed the substring to startsWith for all cases.

Out of curiosity I did some basic benchmarks on some files I had:

*Substring is the original implementation
*StartsWith is the new implementation
*Char is experimental implementation that operates on char[] instead of String, but makes it less readable (so imo not worth it unless someone is parsing thousands of massive templates at once)

test name	ops/s	size in chars	ops/s * size
EscapeChangePerf.benchTinySubstring	2,059,220	34	70,013,489
EscapeChangePerf.benchTinyStartsWith	3,154,894	34	107,266,400
EscapeChangePerf.benchTinyChar	10,831,791	34	368,280,883

EscapeChangePerf.benchSmallSubstring	75,085	966	72,532,051
EscapeChangePerf.benchSmallStartsWith	128,906	966	124,522,734
EscapeChangePerf.benchSmallChar	455,153	966	439,677,458

EscapeChangePerf.benchMediumSubstring	7,465	5,403	40,330,775
EscapeChangePerf.benchMediumStartsWith	24,014	5,403	129,749,603
EscapeChangePerf.benchMediumChar	96,988	5,403	524,023,722

EscapeChangePerf.benchLargeSubstring	628	22,556	14,165,145
EscapeChangePerf.benchLargeStartsWith	5,713	22,556	128,858,481
EscapeChangePerf.benchLargeChar	21,201	22,556	478,209,418

parrt commented 4 years ago

Ok, looks great. Thanks guys.

antlr / stringtemplate4