Speed up the lexer for Ruby 3.4+ (#1832)

* Speed up lexing

* Bump msrv to 3.0 (from 2.7)

* Normalize test for ruby-head compat

* Fix bug when parsing negative numbers

performance/benchmark.rb

@@ -3,6 +3,7 @@
 require 'benchmark/ips'
 require_relative 'theme_runner'
 
+RubyVM::YJIT.enable if defined?(RubyVM::YJIT)
 Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
 profiler = ThemeRunner.new
 

performance/unit/lexer_benchmark.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "benchmark/ips"
+
+# benchmark liquid lexing
+
+require 'liquid'
+
+RubyVM::YJIT.enable
+
+EXPRESSIONS = [
+  "foo[1..2].baz",
+  "12.0",
+  "foo.bar.based",
+  "21 - 62",
+  "foo.bar.baz",
+  "foo > 12",
+  "foo < 12",
+  "foo <= 12",
+  "foo >= 12",
+  "foo <> 12",
+  "foo == 12",
+  "foo != 12",
+  "foo contains 12",
+  "foo contains 'bar'",
+  "foo != 'bar'",
+  "'foo' contains 'bar'",
+  '234089',
+  "foo | default: -1",
+]
+
+EXPRESSIONS.each do |expr|
+  lexer_1_result = Liquid::Lexer1.new(expr).tokenize
+  lexer_2_result = Liquid::Lexer2.new(expr).tokenize
+
+  next if lexer_1_result == lexer_2_result
+
+  warn "Lexer1 and Lexer2 results are different for expression: #{expr}"
+  warn "expected: #{lexer_1_result}"
+  warn "got: #{lexer_2_result}"
+  abort
+end
+
+Benchmark.ips do |x|
+  x.config(time: 10, warmup: 5)
+
+  x.report("Liquid::Lexer1#tokenize") do
+    EXPRESSIONS.each do |expr|
+      l = Liquid::Lexer1.new(expr)
+      l.tokenize
+    end
+  end
+
+  x.report("Liquid::Lexer2#tokenize") do
+    EXPRESSIONS.each do |expr|
+      l = Liquid::Lexer2.new(expr)
+      l.tokenize
+    end
+  end
+
+  x.compare!
+end