[fish] Added script for dealing with Emacs vterm

All credits go to akermu: https://github.com/akermu/emacs-libvterm

shells/fish/conf.d/90-emacs-vterm.fish

@@ -0,0 +1,40 @@
+function vterm_printf;
+    if [ -n "$TMUX" ]
+        # tell tmux to pass the escape sequences through
+        printf "\ePtmux;\e\e]%s\007\e\\" "$argv"
+    else if string match -q -- "screen*" "$TERM"
+        # GNU screen (screen, screen-256color, screen-256color-bce)
+        printf "\eP\e]%s\007\e\\" "$argv"
+    else
+        printf "\e]%s\e\\" "$argv"
+    end
+end
+
+function vterm_prompt_end;
+    vterm_printf '51;A'(whoami)'@'(hostname)':'(pwd)
+end
+functions --copy fish_prompt vterm_old_fish_prompt
+function fish_prompt --description 'Write out the prompt; do not replace this. Instead, put this at end of your file.'
+    # Remove the trailing newline from the original prompt. This is done
+    # using the string builtin from fish, but to make sure any escape codes
+    # are correctly interpreted, use %b for printf.
+    printf "%b" (string join "\n" (vterm_old_fish_prompt))
+    vterm_prompt_end
+end
+
+function vterm_cmd --description 'Run an Emacs command among the ones been defined in vterm-eval-cmds.'
+    set -l vterm_elisp ()
+    for arg in $argv
+        set -a vterm_elisp (printf '"%s" ' (string replace -a -r '([\\\\"])' '\\\\\\\\$1' $arg))
+    end
+    vterm_printf '51;E'(string join '' $vterm_elisp)
+end
+
+function find_file
+    set -q argv[1]; or set argv[1] "."
+    vterm_cmd find-file (realpath "$argv")
+end
+
+function say
+    vterm_cmd message "%s" "$argv"
+end