A new Help Engine with templating capabilities
This set of commits brings a new Help System to CLAP.
Major changes are:
- The help format is (almost) completely defined in `help.rs` instead of being scattered across multiple files.
- The HELP object contains a writer and its methods accept AnyArgs, not the other way around.
- A template option allows the user to change completely the organization of the autogenerated help.
`write_nspaces` has three differences with `write_spaces`
1. Accepts arguments with attribute access (such as self.writer)
2. The order of the arguments is swapped to make the writer the first
argument as in other write related macros.
3. Does not use the `write!` macro under the hood but rather calls
directly `write`
I have chosen to put the function under a new name to avoid backwards
compatibility problem but it might be better to migrate everything to
`write_nspaces` (and maybe rename it `write_spaces`)
Adds a crate_authors! macro that fetches
crate authors from a (recently added)
cargo enviromental variable populated
from the Cargo file. Like the
crate_version macro.
Closes#447
Tons of code has been moved into functions, deduplicated, made much
easier to read, maintain, and understand. Comments still need to be
added, but that will happen shortly. Modules have also been moved around
to follow Rust conventions and best practices.
All functionality remains exactly the same
As of https://github.com/rust-lang/cargo/pull/1094, cargo publishes the full crate version as `CARGO_PKG_VERSION`, rather than *just* the parts of it.
This replaces the more complicated call with simply `env!("CARGO_PKG_VERSION").to_owned()`.
Long help strings can now be broken up with newlines that will be
properly aligned in help messages. Simply place a `{n}` wherever you'd
like the newline to appear.
Closes#145
Allows creating help messages with a more unified look, similar to how
docopt and getopts are formatted. (i.e. flags and options are combined
into a single group)
Closes#158
