wrote opening url in kak post

content/blog/kak/url-open.md

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+---
+title: Opening URLs In Kakoune
+date: 07 Jul 2025
+---
+
+[Kakoune]: https://kakoune.org
+
+One feature built into [Helix](https://docs.helix-editor.com/) is the
+ability to super-easily open URLs in your browser. All you need to do is
+move your cursor over a URL, and press `gf`. This is _very_ helpful when
+reading documentation, emails, et cetera...
+
+So, how can we do this in [Kakoune]?
+
+[TOC]
+
+## Goal
+
+Here's our target user experience:
+
+1. The user moves their cursor over a URL.
+2. The user presses a key.
+3. The URL is selected, validated, and opened.
+4. The user is notified of any errors or success.
+
+Like any bit of custom functionality, the best way to go is to define a
+**command**. This gives us re-usability, and greater flexibility (since
+`map` only allows mapping to _key sequences_, not any arbitrary string of
+commands).
+
+## Selecting
+
+First, we need to find the URL under the cursor. Of course, if there
+_isn't_ one, we should fail at this step. The standard way to do this in
+Kakoune is by using a regular expression to filter the selection. If
+there's no matches at all, that's something we can `try/catch`.
+
+We won't get far without a URL regex. When I'm including long regexes in
+`#!kak execute-keys` commands, I like saving them to a register, like so:
+
+```kak
+set-register b 'https?://(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)'
+```
+
+Then, we just need to check if this regex exists around the user's cursor.
+Since URLs don't have spaces, we can select the surrounding `WORD`, and
+filter from there:
+
+```kak
+execute-keys -draft '<a-a><a-w>s<c-r>b<ret>"ay'
+```
+
+The above command selects the outer `WORD`, then runs the select command
+with our regex (stored in register `b`). Once the URL has been selected,
+it's copied to the `a` register. If there is no URL, the command fails.
+
+## Cleaning
+
+It's usually better to allow regex to be a bit greedier, and then
+filter unwanted characters out of the result. In our case, some
+trailing punctuation is included in the capture -- we can use `sed`
+in a shell block to strip them.
+
+```sh
+clean_url="$(echo "$kak_reg_a" | sed 's/[][(){}.,;!?]*$//')"
+```
+
+## Opening
+
+Our next step is to figure out how we'd open a URL from the shell --
+after all, anything we implement in Kakoune ends up running shell
+commands! If you have `xdg-open` available (part of the `xdg-utils`
+package on Arch Linux), this is simple:
+
+```sh
+xdg-open https://ficd.ca
+```
+
+XDG handles figuring out the correct application to forward the URL to. If
+your environment is set up properly, this is probably your default
+browser. If you don't have (or don't want to use) `xdg-open`, most
+browsers let you open URLs from the command line directly:
+
+```sh
+firefox https://ficd.ca
+```
+
+Depending on the browser -- if you already have an open session, the link
+will be opened as a new tab in an existing window. Nice!
+
+Let's define an **option** which contains the shell command we'll
+use to open the link:
+
+```kak
+# %s gets replaced with the URL
+declare-option str url_open_cmd 'xdg-open %s'
+```
+
+Then, in our shell block, we can substitute the cleaned URL into the `%s`
+format specifier, and evaluate the resulting string as a command:
+
+```sh
+if eval "$(printf "$kak_opt_url_open_cmd" "$clean_url")" >/dev/null 2>&1; then
+    echo "info -title 'URL Opened' '$clean_url'"
+else
+    echo "fail 'url_open_cmd failed!'"
+fi
+```
+
+## Completed Plugin
+
+That's it, that's all! We now have a command called `url-open`,
+which we can easily bind to something like `gu`:
+
+```kak
+map global goto u '<esc>: url-open<ret>'
+```
+
+Here's the complete plugin code:
+
+```kak
+declare-option -docstring %{
+    Command for opening URLs.
+} str url_open_cmd 'xdg-open %s'
+define-command -docstring %{
+    Open the URL the cursor is on with url_open_cmd.
+} url-open %{
+    evaluate-commands -save-regs 'ab' %{
+        set-register b 'https?://(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)'
+        try %{
+            try %{
+                execute-keys -draft '<a-a><a-w>s<c-r>b<ret>"ay'
+            } catch %{
+                fail 'No URL found!'
+            }
+            evaluate-commands %sh{
+                # strip trailing punctuation
+                clean_url="$(echo "$kak_reg_a" | sed 's/[][(){}.,;!?]*$//')"
+                if eval "$(printf "$kak_opt_url_open_cmd" "$clean_url")" >/dev/null 2>&1; then
+                    echo "info -title 'URL Opened' '$clean_url'"
+                else
+                    echo "fail 'url_open_cmd failed!'"
+                fi
+            }
+        } catch %{
+            info -title 'URL Open' "Couldn't open URL: %val{error}"
+        }
+    }
+}
+```
+