nixpkgs/lib/cli.nix
Gabriel Gonzalez 693096d283 Make behavior of encodeGNUCommandLine customizable
... based on feedback from @edolstra
2019-12-13 18:25:52 -08:00

38 lines
1.1 KiB
Nix

{ lib }:
{ /* Automatically convert an attribute set to command-line options.
This helps protect against malformed command lines and also to reduce
boilerplate related to command-line construction for simple use cases.
Example:
encodeGNUCommandLine { } { foo = "A"; bar = 1; baz = null; qux = true; v = true; }
=> " --bar '1' --foo 'A' --qux -v"
*/
encodeGNUCommandLine =
{ renderKey ?
key: if builtins.stringLength key == 1 then "-${key}" else "--${key}"
, renderOption ?
key: value:
if value == null
then ""
else " ${renderKey key} ${lib.escapeShellArg value}"
, renderBool ? key: value: if value then " ${renderKey key}" else ""
, renderList ? key: value: lib.concatMapStrings renderOption value
}:
options:
let
render = key: value:
if builtins.isBool value
then renderBool key value
else if builtins.isList value
then renderList key value
else renderOption key value;
in
lib.concatStrings (lib.mapAttrsToList render options);
}