Reprocess Escape Sequences

[Nathaniel Madura]

I am getting a string that has escape sequences in it, and I would like
to print it to the screen after reprocessing the escape sequences. Maybe
I have missed something obvious but I haven't seen anything in the docs
that suggest how to do this. To replicate the behaviour I create a
string in irb like so:

$ irbsome \n\r string \t with \r escape \n sequences
=> nilsome \n\r string \t with \r escape \n sequences
=> nil

I recognize that I can simply do a gsub:
some
\r string \t with \r escape
sequences
=> nil

but that would mean I would have to pattern match all sequences, and it
seems like there should be a better way

Any suggestions?

 

[Robert Klemme]

I am getting a string that has escape sequences in it, and I would like
to print it to the screen after reprocessing the escape sequences. Maybe
I have missed something obvious but I haven't seen anything in the docs
that suggest how to do this. To replicate the behaviour I create a
string in irb like so:

$ irb
some \n\r string \t with \r escape \n sequences
=3D> nil

If you use eval you rather need to do something like this

irb(main):004:0> str =3D 'some \n\r string \t with \r escape \n sequences'
=3D> "some \\n\\r string \\t with \\r escape \\n sequences"
irb(main):005:0> puts eval('"'+str+'"')
some
escape with
sequences
=3D> nil
irb(main):006:0>

some \n\r string \t with \r escape \n sequences
=3D> nil

I recognize that I can simply do a gsub:

some
\r string \t with \r escape
=A0sequences
=3D> nil

but that would mean I would have to pattern match all sequences, and it
seems like there should be a better way

Actually doing a replacement would probably be my preferred way
because of the security implications of eval.

You can do it in one go

irb(main):008:0> PAT =3D {'n'=3D>"\n",'t'=3D>"\t",'r'=3D>"\r"}
=3D> {"n"=3D>"\n", "t"=3D>"\t", "r"=3D>"\r"}
irb(main):009:0> str.gsub(/\\(.)/){|m| PAT[$1]}
=3D> "some \n\r string \t with \r escape \n sequences"

Kind regards

robert

--=20
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