Use Regexp instead of // for regex in router.rb for a more efficient …

…string allocation.

Changelog

CHANGELOG.md

@@ -3,7 +3,7 @@
 #### Features
 
 * Your contribution here.
-* [#1942](https://github.com/ruby-grape/grape/pull/1942): Optimized retained memory methods - [@ericproulx](https://github.com/ericproulx).
+* [#1943](https://github.com/ruby-grape/grape/pull/1943): Reduce number of regex string allocations - [@ericproulx](https://github.com/ericproulx).
 * [#1941](https://github.com/ruby-grape/grape/pull/1941): Frozen string literal - [@ericproulx](https://github.com/ericproulx).
 * [#1940](https://github.com/ruby-grape/grape/pull/1940): Get rid of a needless step in HashWithIndifferentAccess - [@dnesteryuk](https://github.com/dnesteryuk).
 * [#1938](https://github.com/ruby-grape/grape/pull/1938): Add project metadata to the gemspec - [@orien](https://github.com/orien).

lib/grape/router.rb

@@ -38,7 +38,7 @@ def compile!
  routes = map[method]
  @optimized_map[method] = routes.map.with_index do |route, index|
  route.index = index
- route.regexp = /(?<_#{index}>#{route.pattern.to_regexp})/
+ route.regexp = Regexp.new("(?<_#{index}>#{route.pattern.to_regexp})")
  end
  @optimized_map[method] = Regexp.union(@optimized_map[method])
  end
@@ -50,7 +50,7 @@ def append(route)
  end
 
  def associate_routes(pattern, **options)
- regexp = /(?<_#{@neutral_map.length}>)#{pattern.to_regexp}/
+ regexp = Regexp.new("(?<_#{@neutral_map.length}>)#{pattern.to_regexp}")
  @neutral_map << Any.new(pattern, regexp: regexp, index: @neutral_map.length, **options)
  end