Crate kurisu_derive

Provides derive(Kurisu) for the Kurisu crate.

The Kurisu derive macro is not meant to do any validation nor display usage for the command line string values. It will only construct kurisu::Arg structs according to a given Rust Struct, and put them within a function get_info_instance wrapped by a once_cell static instance of a kurisu::Info struct.

Example:

use kurisu::*;

#[derive(Debug, Kurisu)]
struct Yargs {
    knots: usize,
}

fn main() {
    let env_vars: Vec<String> = std::env::args().skip(1).collect();

    // The Derive Macro add `from_args` function to the user's struct,
    // `from_args` will normalize the command line values into kurisu::Info.env_args
    let args = Yargs::from_args(&env_vars);
    
    let knots;
    // This scope is so the mutex guard gets released after
    // we retrieve the information we need.
    {
        // The Derive Macro also add `get_info_instance` function to the user's struct.
        // The Kurisu:Info struct holds all the parsed information the Derive Macro did.
        let info = Yargs::get_info_instance(&env_vars).lock().unwrap();
        knots = info.args.iter().find(|a| a.name == "knots").unwrap().clone();
    }
    
    // If we assume the current example was called as follow: `mycli --knots 8`
    // We would find that information within the Kurisu::Info struct
    assert_eq!(info.env_args, vec!["--knots=8".to_string()]);
    assert_eq!(knots.value, vec!["8".to_string()]);
    assert_eq!(args.knots, 8);
}

Rust types with specific meaning

Type	Description
bool	Defines a Flag
u8	Defines a Flag with occurrence tracking as its value
String	Defines value type of an Option or Argument
PathBuf	Defines value type of an Option or Argument
usize	Defines value type of an Option or Argument
isize	Defines value type of an Option or Argument
f64	Defines value type of an Option or Argument
Vec	Defines a repetitive Option or Argument

Override default behaviors on main Struct

The struct that drives these behaviors is handled by kurisu::Info, most of the annotation are associated to one of its field.

Field name	Default	Annotation	Description
name	“Unknown”	name = “mycli”	Change name on usage screen
version	0	version = “0.1.0”	Change version on usage screen
desc	None	desc = “some short text”	Change description on usage screen
doc	None	///	Change DISCUSSION text on usage screen
allow_noargs	false	allow_noargs	Does not display usage screen if no command line values
		cargo	Will try to fetch name, version & desc from the Cargo.toml, the specific field annotation take precedence on the cargo annotation
		nosort	Avoid sorting alphabetically arguments, flags & options on usage screen
		auto_shorts	Enables the auto generation of short flags / options according to their field’s name first letter, by default no short flags / options are generated unless specified on the struct’s field annotation

Example:

    #[derive(Debug, Kurisu)]
    // Only picks the version from Cargo.toml since name & desc are already present
    #[kurisu(name = "yargs", cargo, desc = "some desc here", auto_shorts)]
    /// This text is for the DISCUSSION
    /// section in the use screen
    ///
    /// It can be a very large text
    struct Yargs {}

Override default behaviors on main Struct’s fields

The struct that drives these behaviors is handled by kurisu::Arg, most of the annotation are associated to one of its field.

Field name	Default	Annotation	Description
vname	field’s name	vname = “myname”	Change the name of the in the usage screen
position	None	pos OR pos = “1”	Defines the position of an argument, pos without a value defines an infinite positional argument
doc	None	///	Defines the description of arg on the usage screen
short	None	short OR short = “b”	Change the letter used by short flag / option, otherwise it takes the first letter of the struct’s field name
long	field’s name	nolong OR long = “myname”	Change or remove the long flag / option
env	field’s name	env = “MYSQL_HOST”	By default the field’s name is used to look for environment variable match as last resort, this is to change which environment variable is being matched
env_prefix	None	env_prefix = “MYSQL_”	Will take the field’s name and prefix it and look for a match environment variable
required_if	None	required_if = “fieldname”	Will make this option required if the other flag/option is present
default	“”	default = “42”	If not present in the command line values, struct field will be assigned this default value instead of default type value
exit	None	exit = “my_exit_func”	Local function that triggers std::process::exit() after being executed. A bit like the usage display, it will stop execution at from_args
		parse_with = “my_func”	Local function that allows custom parsing for this argument/flag/option

Example:

use std::path::PathBuf;

#[derive(Debug, Kurisu)]
struct Yargs {
    #[kurisu(pos = 1)]
    file: PathBuf,
    #[kurisu(pos)] // Infinite positional argument
    others: String,
    #[kurisu(short, nolong, env_prefix = "MYSQL_")]
    host: String,
    #[kurisu(long = "very-long-flag")]
    more: bool,
    /// description for `crashed` on usage screen
    crashed: bool,
}

Derive Macros

Kurisu