function _nix_complete # Get the current command up to a cursor. # - Behaves correctly even with pipes and nested in commands like env. # - TODO: Returns the command verbatim (does not interpolate variables). # That might not be optimal for arguments like -f. set -l nix_args (commandline --current-process --tokenize --cut-at-cursor) # --cut-at-cursor with --tokenize removes the current token so we need to add it separately. # https://github.com/fish-shell/fish-shell/issues/7375 # Can be an empty string. set -l current_token (commandline --current-token --cut-at-cursor) # Nix wants the index of the argv item to complete but the $nix_args variable # also contains the program name (argv[0]) so we would need to subtract 1. # But the variable also misses the current token so it cancels out. set -l nix_arg_to_complete (count $nix_args) env NIX_GET_COMPLETIONS=$nix_arg_to_complete $nix_args $current_token 2>/dev/null end function _nix_accepts_files set -l response (_nix_complete) test $response[1] = 'filenames' end function _nix set -l response (_nix_complete) # Skip the first line since it handled by _nix_accepts_files. # Tail lines each contain a command followed by a tab character and, optionally, a description. # This is also the format fish expects. string collect -- $response[2..-1] end # Disable file path completion if paths do not belong in the current context. complete --command nix --condition 'not _nix_accepts_files' --no-files complete --command nix --arguments '(_nix)'