Wraps around Haskell LSP servers and runs one in nix-shell if available. Requires yq if hie.yaml is present.

hls-wrapper.sh

#!/usr/bin/env bash

SERVERS=( haskell-language-server-wrapper hie-wrapper haskell-language-server hie ghcide )
SERVER=
SERVER_PATH=

NIX_FILES=( shell.nix default.nix nix/shell.nix nix/default.nix )

NIX_CMD=

HIE_CRADLE=

for srv in ${SERVERS[@]}; do
    if hash "$srv"; then
        SERVER="$srv"
        SERVER_PATH="$(which "$srv")"
        SERVER_PATH="$(dirname "$SERVER_PATH")"
        break
    fi
done

if [ -z "$SERVER" ]; then
    echo "Unable to locate any Haskell LSP servers. Exiting."
    exit 1
fi

for f in ${NIX_FILES[@]}; do
    if test -f "$f"; then 
        NIX_CMD="nix-shell $f --run bash"
        break
    fi
done

SHELL_CMD=$(cat <<- EOF
export PATH="$SERVER_PATH:$PATH"
$SERVER $@
EOF
)

if test -f hie.yaml; then
    HIE_CRADLE=$(cat hie.yaml | yq ".cradle | keys | .[0]" | tr -d '"')
fi

# Stack doesn't work inside nix-shell, so we don't wanna run it that way.
# Hence, if nix-shell is available, run anything but stack there.
# Otherwise run without nix-shell.
if [ "$HIE_CRADLE" != "stack" ] && [ ! -z "$NIX_CMD" ]; then
    $NIX_CMD <<< "$SHELL_CMD"
else
    $SERVER $@
fi