fish-shell/share/functions/realpath.fish

# Provide a minimalist realpath implementation to help deal with platforms that may not provide it
# as a command. If an external realpath or grealpath command is available simply pass all arguments
# thru to it. If not fallback to our builtin.

# The following is slightly subtle. We have to define a realpath function even if there is an
# external command by that name. That's because if we don't the parser will select our builtin.
# However, we only want our builtin if there is no external realpath command.

if command -sq realpath
    function realpath -w realpath -d "print the resolved path [command realpath]"
        command realpath $argv
    end
    exit 0
end

# If there is a HomeBrew installed version of GNU realpath named grealpath use that.
if command -sq grealpath
    function realpath -w grealpath -d "print the resolved path [command grealpath]"
        command grealpath $argv
    end
    exit 0
end

function realpath -d "return an absolute path without symlinks"
    set -l options h/help q/quiet V-version s/no-symlinks N-strip z/zero
    set -a options e/canonicalize-existing m/canonicalize-missing L/logical P/physical
    set -a options 'R-relative-to=' 'B-relative-base='
    argparse -n realpath $options -- $argv
    or return

    if set -q _flag_help
        __fish_print_help realpath
        return 0
    end

    set -l supported_flags
    if set -el _flag_no_symlinks
        set -el _flag_s
        set -a supported_flags --no-symlinks
    end

    # We don't implement any of the other flags so if any are set it's an error.
    if string match -q '_flag_*' -- (set -l)
        set -l flags (set -l | string replace --filter --regex '_flag_\w+\s*' '' | sort -u)
        printf (_ "%s: These flags are not allowed by fish realpath: '%s'") realpath "$flags" >&2
        echo >&2
        __fish_print_help realpath
        return 1
    end

    if not set -q argv[1]
        printf (_ "%ls: Expected at least %d args, got only %d\n") realpath 1 0 >&2
        return 1
    end

    for path in $argv
        builtin realpath $supported_flags $path
    end
end