Bugfix/#967 fish shell support (#968)

* Add support for fish shell

* Simplify ELS_ELIXIR_OPTS

* Refactor ELS_ELIXIR_OPTS and ELS_ERL_OPTS argument builder

* Escape strings in test calls

* Remove unnecessary quotes in set els_dir

* Fix asdf detection

* Replace . with source

scripts/launch.fish

@@ -0,0 +1,89 @@
+#!/usr/bin/env fish
+# Actual launcher. This does the hard work of figuring out the best way
+# to launch the language server or the debugger.
+
+# Running this script is a one-time action per project launch, so we opt for
+# code simplicity instead of performance. Hence some potentially redundant
+# moves here.
+
+# First order of business, see whether we can setup asdf-vm
+
+set asdf_dir $ASDF_DIR
+
+test -z "$asdf_dir"; and set asdf_dir "$HOME/.asdf"
+
+set asdf_vm "$asdf_dir/asdf.fish"
+
+echo "Looking for ASDF install" >&2
+
+if test -f "$asdf_vm"
+  echo "ASDF install found in $asdf_vm, sourcing" >&2
+  source "$asdf_vm"
+else
+  echo "ASDF not found" >&2
+  echo "Looking for rtx executable" >&2
+
+  set rtx (which rtx)
+  if test -n "$rtx"
+    echo "rtx executable found in $rtx, activating" >&2
+    "$rtx" activate fish | source
+  else
+    echo "rtx not found" >&2
+  end
+end
+
+# In case that people want to tweak the path, which Elixir to use, or
+# whatever prior to launching the language server or the debugger, we
+# give them the chance here. ELS_MODE will be set for
+# the really complex stuff. Use an XDG compliant path.
+
+set els_dir $XDG_CONFIG_HOME
+test -z "$els_dir"; and set els_dir "$HOME/.config"
+
+set els_setup "$els_dir/elixir_ls/setup.fish"
+
+if test -f "$els_setup"
+  echo "Running setup script $els_setup" >&2
+  source "$els_setup"
+end
+
+# Setup done. Make sure that we have the proper actual path to this
+# script so we can correctly configure the Erlang library path to
+# include the local .ez files, and then do what we were asked to do.
+
+function readlink_f
+  cd (dirname $argv[1]) || exit 1
+  set filename (basename $argv[1])
+  if test -L $filename
+    readlink_f (readlink $filename)
+  else
+    echo (pwd -P)"/$filename"
+  end
+end
+
+if test -z "$ELS_INSTALL_PREFIX"
+  set scriptpath (dirname (readlink_f (status -f)))
+else
+  set scriptpath $ELS_INSTALL_PREFIX
+end
+
+set -x MIX_ENV prod
+# Mix.install prints to stdout and reads from stdin
+# we need to make sure it doesn't interfere with LSP/DAP
+echo "" | elixir "$scriptpath/quiet_install.exs" >/dev/null || exit 1
+
+set erl_opts -kernel standard_io_encoding latin1 +sbwt none +sbwtdcpu none +sbwtdio none
+
+if test -n "$ELS_ELIXIR_OPTS"
+  set elixir_opts (string join ' ' -- $ELS_ELIXIR_OPTS)
+else
+  set elixir_opts
+end
+
+if test -n "$ELS_ERL_OPTS"
+  set erl_opts -a $ELS_ERL_OPTS
+end
+
+set erl_opts (string join ' ' -- $erl_opts)
+
+eval elixir $elixir_opts --erl \"$erl_opts \" "$scriptpath/launch.exs"

scripts/launch.sh

@@ -21,6 +21,9 @@ case "${did_relaunch}" in
     elif [ "$preferred_shell" = "zsh" ]; then
       >&2 echo "Preffered shell is zsh, relaunching"
       exec "$(which zsh)" "$0" relaunch
+    elif [ "$preferred_shell" = "fish" ]; then
+      >&2 echo "Preferred shell is fish, launching launch.fish"
+      exec "$(which fish)" "$(dirname "$0")/launch.fish"
     else
       >&2 echo "Preffered shell $preferred_shell is not supported, continuing in POSIX shell"
     fi