Arg - Aspect Build

Arg is the opaque value returned by the args builders (args.string, args.int, args.boolean, args.string_list, args.trailing_var_args, args.positional, args.custom, and their list variants). An Arg is a declaration — a schema entry that tells a task how to parse, validate, and default a single argument. You do not construct or mutate an Arg directly; you obtain one from an args.* builder and place it in a task’s args map. At invocation time, the parsed value is delivered to your implementation through the Arguments object, keyed by the map’s name.

Usage

Use an Arg as the value in a task’s args dictionary. The dictionary key becomes the argument’s name — that name is derived to kebab-case for the CLI flag (snake_case_name → --snake-case-name) unless you pass long = "override-name" on the builder.

def _impl(ctx: TaskContext):
    mode = ctx.args.get("mode")
    tags = ctx.args.get("tags")

my_task = task(
    implementation = _impl,
    args = {
        "mode": args.string(default = "auto", values = ["auto", "on", "off"]),
        "tags": args.string_list(),
        "verbose": args.boolean(default = False, short = "v"),
    },
)

args — builders that produce an Arg.
Arguments — the parsed args passed to a task implementation, including is_explicit to detect CLI-supplied values.
Task.alias — override an existing Arg’s default without redefining it.

​Usage

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Usage

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