Faster scanner

[tenderlove]

This commit speeds up the scanner by using instance variables for storing line / column information (rather than a hash).

IVs have faster read / write speeds than hash keys

I couldn't get the c ext to build, so I commented it out from the benchmarks.

On master:

$ bundle exec ruby -S rake bench:scan
Warming up --------------------------------------
scan - introspection   315.000  i/100ms
    scan - fragments   463.000  i/100ms
    scan - big query    52.000  i/100ms
Calculating -------------------------------------
scan - introspection      3.153k (± 0.7%) i/s -     16.065k in   5.096124s
    scan - fragments      4.638k (± 0.7%) i/s -     23.613k in   5.091799s
    scan - big query    524.253  (± 0.6%) i/s -      2.652k in   5.058781s

This branch:

$ bundle exec ruby -S rake bench:scan
Warming up --------------------------------------
scan - introspection   358.000  i/100ms
    scan - fragments   523.000  i/100ms
    scan - big query    60.000  i/100ms
Calculating -------------------------------------
scan - introspection      3.587k (± 0.4%) i/s -     18.258k in   5.090098s
    scan - fragments      5.305k (± 0.5%) i/s -     26.673k in   5.028207s
    scan - big query    600.081  (± 0.3%) i/s -      3.060k in   5.099354s

Seems about 14% faster on big queries.

Again with YJIT:

master:

$ bundle exec ruby --jit -S rake bench:scan
Warming up --------------------------------------            
scan - introspection   486.000  i/100ms                      
    scan - fragments   714.000  i/100ms                      
    scan - big query    80.000  i/100ms                      
Calculating -------------------------------------            
scan - introspection      4.855k (± 0.3%) i/s -     24.300k in   5.004814s
    scan - fragments      7.124k (± 0.4%) i/s -     35.700k in   5.011340s
    scan - big query    805.246  (± 0.5%) i/s -      4.080k in   5.066896s

This branch:

$ bundle exec ruby --jit -S rake bench:scan
Warming up --------------------------------------
scan - introspection   557.000  i/100ms
    scan - fragments   825.000  i/100ms
    scan - big query    94.000  i/100ms
Calculating -------------------------------------
scan - introspection      5.599k (± 0.3%) i/s -     28.407k in   5.074005s
    scan - fragments      8.313k (± 0.3%) i/s -     42.075k in   5.061280s
    scan - big query    943.246  (± 0.3%) i/s -      4.794k in   5.082520s

[rmosolgo]

Thanks for this improvement! I moved replace_escaped_characters_in_place back to being a class method because the C parser actually calls out to it 🙈 (I didn't dare try to re-implement it without Ruby....).