torque
0d091611dd
This is the first cut at providing human-readable context for command line parsing failures. Since these failures are due to incorrect input (normally produced by a human), closing the information loop at the human layer makes a hell of a lot more sense than dumping an error traceback with a (possibly cryptic) error name and calling it a day. This approach doesn't print anything out by default and still depends on the user to choose exactly how the handle and print the error message. Errors are propagated from subcommands, though they end up being copied, which shouldn't be strictly necessary. Maybe this can be improved in the future. OutOfMemory has been added to ParseError to simplify the code a bit. The demo has been updated with a simplistic example of what presenting error messages to the user may look like. I don't know that this produces useful messages for every possible failure scenario, but it does for the most common ones.
== nearly obvious command line interface parser
A zig library for composing declarative command-line interfaces. Heavily
inspired by https://click.palletsprojects.com/[click] for Python.
== Extemporaneous Bloviation
[quote, George "Albert Einstein" Washington]
____
The alarm rings, and expletives spill from my mouth—instinctively, before any
neuron has a chance to fire. You'd think this would get easier, having done it
at least 12000 times, but I guess it just goes to show that practice does not
necessarily converge on perfection, no matter what infinite limit t approaches.
Eyes clamped shut against the encroaching underglow spilling from the curtains,
I stretch my arms straight out from my sides and proceed to lose my balance,
flying horizontally off of the mattress. An attempt at attitude control fails
vigorously and I begin cartwheeling through open space, asserting a lopsided
trajectory that intersects with the roof of the house. Passing through it
unencumbered, I careen skyward and watch the ground recede into the distance,
as the features of the landscape shrink and pop out of existence.
____
== Hello
Requires Zig `0.11.x`.
=== Features
WARNING: NOCLIP is usable but not currently mature or well-tested. Unfinished features
and bugs likely exist.
* highly configurable short/long option and argument specification
** named options can be associated with an environment variable
** named flags, which take no value and can be biased `true` or `false`
** multiple specification options, which can be provided many times to the CLI
** overridable built-in conversion functions for standard types
** required options that must be specified by the user
** default values for options
* arbitrarily nestable subcommands for building sophisticated tools
* parser that supports many conventional CLI behaviors
** congealed short flags (e.g. `-abc` is the same as `-a -b -c`)
** `--` to force early end of flag parsing
** both `--long value` and `--long=value` styles are supported
* option values are converted into rich native types using conversion callback functions
** integers
** basic tuple values
** strings
** enumerations as named choice sets
** more to come
* automatic help text generation and formatting
* CLI specification and parser are built at compile time
=== Use
`zig build demo` for a demo. Otherwise just copy the file or use a submodule or
something.
----
Usage: noclip-demo [options...] <arg> <subcommand ...>
The definitive noclip demonstration utility
This command demonstrates the functionality of the noclip library. cool!
Arguments:
arg This is an argument that doesn't really do anything, but it's very
important.
Options:
-t, --test <int> <int> multi-value test option (env: NOCLIP_TEST)
-c, --choice <choice> enum choice option (env: NOCLIP_CHOICE) (default: demo.Choice.second)
-d, --default <uint> default value integer option (env: NOCLIP_DEFAULT) (default: 100)
-m, --multi <u8> multiple specification test option
-f, --flag / -F, --no-flag boolean flag (env: NOCLIP_FLAG)
-M multiple specification test flag
Environment variables:
NOCLIP_ENVIRON environment variable only option
Subcommands:
verb Perform some sort of work
----
== LICENSE
INTERNET SOFTWARE CONSORTIUM LICENSE