Question

Try the following code:

s = '#value#'
puts s.gsub('#value#', Regexp.escape('*'))         # => '\*'
puts s.gsub('#value#', Regexp.escape('+'))         # => ''

Wtf? It looks like the char '\+' (returned by Regexp.escape) is completely ignored by gsub. How to fix this?

Answer 1

xsdg of #ruby worked this out

Looks like that gsub’s replacement is parsed, so the + is lost somewhere in the process. A workaround is using gsub’s block syntax. This way:

s = '#value#'
puts s.gsub('#value#') { |v| Regexp.escape('+') }          # => '+'

Works as expected 🙂

Thanks, xsdg!