Expand the help message printed from --help.

Fixes #10. I consider this a temporary measure, however, until nix-repl has a
manpage (see #14). Then it can just open its manpage on --help like the other
nix tools do.

Much of the text in this commit was copied from nix-build's manpage.
This commit is contained in:
Scott Olson 2016-02-18 04:05:11 -06:00
parent dc8b51754b
commit 287dfee35e

View file

@ -59,8 +59,35 @@ struct NixRepl
void printHelp()
{
std::cout << "Usage: nix-repl [--help|--version]";
std::cout << std::endl;
cout << "Usage: nix-repl [--help] [--version] [-I path] paths...\n"
<< "\n"
<< "nix-repl is a simple read-eval-print loop (REPL) for the Nix package manager.\n"
<< "\n"
<< "Options:\n"
<< " --help\n"
<< " Prints out a summary of the command syntax and exits.\n"
<< "\n"
<< " --version\n"
<< " Prints out the Nix version number on standard output and exits.\n"
<< "\n"
<< " -I path\n"
<< " Add a path to the Nix expression search path. This option may be given\n"
<< " multiple times. See the NIX_PATH environment variable for information on\n"
<< " the semantics of the Nix search path. Paths added through -I take\n"
<< " precedence over NIX_PATH.\n"
<< "\n"
<< " paths...\n"
<< " A list of paths to files containing Nix expressions which nix-repl will\n"
<< " load and add to its scope.\n"
<< "\n"
<< " A path surrounded in < and > will be looked up in the Nix expression search\n"
<< " path, as in the Nix language itself.\n"
<< "\n"
<< " If an element of paths starts with http:// or https://, it is interpreted\n"
<< " as the URL of a tarball that will be downloaded and unpacked to a temporary\n"
<< " location. The tarball must include a single top-level directory containing\n"
<< " at least a file named default.nix.\n"
<< flush;
}