Feature Request: Add support for hyperlinks with -R

[tomprince]

There is a standard for displaying hyperlinks in terminals here. It would be nice if less passed through those escapes when -R is passed, like it does colors.

(Originally reported as 308 on the bug list)

There is a patch here (from here).

[poettering]

Note that bigger projects including gcc and systemd nowadays generate hyperlinks like that in their output. It would be excellent if less would handle this correctly!

(I am systemd maintainer)

[dandavison]

In case it helps the process of getting this feature into master, I have applied the patch (with minor modifications to fix the conflicts) on master, confirmed that hyperlinks are working, and opened a PR: #75.

(My motivation for this is that I'm the author of an application that relies on less for paging and would like to use hyperlinks: dandavison/delta#261.)

[torarnv]

If adding to what -R does is seen as too risky for backwards compatibility, perhaps a new environment variable similar to LESSANSIENDCHARSand LESSANSIMIDCHARS could be added that controls which control codes to pass through, defaulting to the existing ANSI color escape sequences?

[gwsw]

This is implemented in 3bb781e. My tests with self-constructed files seem to work fine, but could someone who regularly uses files containing such hyperlinks confirm that the behavior is as expected?

[dandavison]

Thanks very much for working on this @gwsw. I have built 3bb781e locally and can confirm that it is working as expected for me.

(The way I tested was a bit idiosyncratic, but for the record I used delta with the setting hyperlinks = true and issued git show. With the version of less that I had installed already, the hyperlink was displayed correctly only if I used the -r flag, but not with -R (as expected). With the version of less built from 3bb781e the hyperlink was displayed correctly when I used less -R and also less -r. So that all matched my expectations. This was on MacOS under iTerm2.).

[tomprince]

I can confirm that 607c9b6 works as expected with hyperlinks. Thanks!

[torarnv]

Can confirm that this works as expected in v570. Thanks!!