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#![warn(missing_docs)]
#![warn(rustdoc::missing_doc_code_examples)]
#![doc = include_str!("../README.md")]
use std::rc::Rc;
use std::str::FromStr;
pub mod params;
mod args;
#[doc(hidden)]
pub mod info;
use crate::{args::Word, info::Error, info::Item};
#[cfg(test)]
mod tests;
#[doc(inline)]
pub use crate::args::Args;
#[doc(inline)]
pub use crate::info::{Info, Meta, OptionParser};
#[doc(inline)]
pub use crate::params::*;
#[cfg(feature = "bpaf_derive")]
pub use bpaf_derive::Bpaf;
/// Compose several parsers to produce a single result
///
/// Every parser must succeed in order to produce a result for
/// sequential composition and only one parser needs to succeed
/// for a parallel one (`construct!([a, b, c])`)
///
/// Each parser must be present in a local scope and
/// have the same name as struct field. Alternatively
/// a parser can be present as a function producing a parser
/// bpaf will call this function and use it's result. Later
/// option might be useful when single parser is used in
/// several `construct!` macros
///
/// ```rust
/// # use bpaf::*;
/// struct Res {
/// a: bool,
/// b: u32,
/// }
///
/// // parser defined as a local variable
/// let a: Parser<bool> = short('a').switch();
///
/// // parser defined as a function
/// fn b() -> Parser<u32> { short('b').argument("B").from_str() }
/// let res: Parser<Res> = construct!(Res { a, b() });
/// # drop(res);
/// ```
///
/// `construct!` supports following representations:
///
/// - structs with unnamed fields:
/// ```rust ignore
/// construct!(Res(a, b))
/// ```
/// - structs with named fields:
/// ```ignore
/// construct!(Res {a, b})
/// ```
/// - enums with unnamed fields:
/// ```ignore
/// construct!(Ty::Res(a, b))
/// ```
/// - enums with named fields:
/// ```ignore
/// construct!(Ty::Res {a, b})
/// ```
/// - tuples:
/// ```ignore
/// construct!(a, b)
/// ```
/// - parallel composition, a equivalent of `a.or_else(b).or_else(c)`
/// ```ignore
/// construct!([a, b, c])
/// ```
#[macro_export]
macro_rules! construct {
// construct!(Cons { a, b, c })
($con:ident { $($tokens:tt)* }) => {{ $crate::construct!(@prepare [named [$con]] [] $($tokens)*) }};
// construct!(Cons ( a, b, c ))
($con:ident ( $($tokens:tt)* )) => {{ $crate::construct!(@prepare [pos [$con]] [] $($tokens)*) }};
// construct!(Enum::Cons { a, b, c })
($ns:ident :: $con:ident { $($tokens:tt)* }) => {{ $crate::construct!(@prepare [named [$ns $con]] [] $($tokens)*) }};
// construct!(Enum::Cons ( a, b, c ))
($ns:ident :: $con:ident ( $($tokens:tt)* )) => {{ $crate::construct!(@prepare [pos [$ns $con]] [] $($tokens)*) }};
// construct!( a, b, c )
($first:ident $($tokens:tt)*) => {{ $crate::construct!(@prepare [pos] [] $first $($tokens)*) }};
// construct![a, b, c]
([$first:ident $($tokens:tt)*]) => {{ $crate::construct!(@prepare [alt] [] $first $($tokens)*) }};
(@prepare $ty:tt [$($fields:tt)*] $field:ident (), $($rest:tt)*) => {{
let $field = $field();
$crate::construct!(@prepare $ty [$($fields)* $field] $($rest)*)
}};
(@prepare $ty:tt [$($fields:tt)*] $field:ident () $($rest:tt)*) => {{
let $field = $field();
$crate::construct!(@prepare $ty [$($fields)* $field] $($rest)*)
}};
(@prepare $ty:tt [$($fields:tt)*] $field:ident, $($rest:tt)*) => {{
$crate::construct!(@prepare $ty [$($fields)* $field] $($rest)*)
}};
(@prepare $ty:tt [$($fields:tt)*] $field:ident $($rest:tt)*) => {{
$crate::construct!(@prepare $ty [$($fields)* $field] $($rest)*)
}};
(@prepare [alt] [$first:ident $($fields:ident)*]) => { $first $(.or_else($fields))* };
(@prepare $ty:tt [$($fields:tt)*]) => {{
$crate::Parser {
parse: ::std::rc::Rc::new(move |args| {
$(let ($fields , args) = ($fields . parse)(args)?;)*
::std::result::Result::Ok(($crate::construct!(@make $ty [$($fields)*]), args))
}),
meta: $crate::Meta::And(::std::vec![ $($fields.meta),* ])
}
}};
(@make [named [$con:ident]] [$($fields:ident)*]) => { $con { $($fields),* } };
(@make [pos [$con:ident]] [$($fields:ident)*]) => { $con ( $($fields),* ) };
(@make [named [$ns:ident $con:ident]] [$($fields:ident)*]) => { $ns :: $con { $($fields),* } };
(@make [pos [$ns:ident $con:ident]] [$($fields:ident)*]) => { $ns :: $con ( $($fields),* ) };
(@make [pos] [$($fields:ident)*]) => { ( $($fields),* ) };
}
#[doc(hidden)]
/// A bit more user friendly alias for parsing function
pub type DynParse<T> = dyn Fn(Args) -> Result<(T, Args), Error>;
/// Simple or composed argument parser
#[derive(Clone)]
pub struct Parser<T> {
#[doc(hidden)]
/// Parsing function
pub parse: Rc<DynParse<T>>,
#[doc(hidden)]
/// Included information about the parser
pub meta: Meta,
}
impl<T> Parser<T> {
/// Wrap a value into a `Parser`
///
/// Parser will produce `T` without consuming anything from the command line, can be useful
/// with [`construct!`].
///
/// ```rust
/// # use bpaf::*;
/// let a = long("flag-a").switch();
/// let b = Parser::pure(42u32);
/// let t: Parser<(bool, u32)> = construct!(a, b);
/// # drop(t)
/// ```
#[must_use]
pub fn pure(val: T) -> Parser<T>
where
T: 'static + Clone,
{
let parse = move |i| Ok((val.clone(), i));
Parser {
parse: Rc::new(parse),
meta: Meta::Id,
}
}
#[doc(hidden)]
/// <*>
#[must_use]
pub fn ap<A, B>(self, other: Parser<A>) -> Parser<B>
where
T: Fn(A) -> B + 'static,
A: 'static,
{
let parse = move |i| {
let (t, rest) = (self.parse)(i)?;
let (a, rest) = (other.parse)(rest)?;
Ok((t(a), rest))
};
Parser {
parse: Rc::new(parse),
meta: self.meta.clone().and(other.meta.clone()),
}
}
/// If first parser fails - try the second one
///
/// ```rust
/// # use bpaf::*;
/// let a = short('a').switch();
/// let b = short('b').switch();
///
/// // Parser will accept either `-a` or `-b` on a command line but not both at once.
/// let a_or_b: Parser<bool> = a.or_else(b);
/// # drop(a_or_b);
/// ```
///
/// # Performance
///
/// If first parser succeeds - second one will be called anyway to produce a
/// better error message for combinations of mutually exclusive parsers:
///
/// Suppose program accepts one of two mutually exclusive switches `-a` and `-b`
/// and both are present error message should point at the second flag
///
/// [`construct!`] can be used to perform a similar task and might generate better code if
/// combines more than two parsers. Those two invocations are equivalent:
///
/// ```ignore
/// let abc = a.or_else(b).or_else(c);
/// ```
/// ```ignore
/// let abc = construct!([a, b, c]);
/// ```
///
#[must_use]
pub fn or_else(self, other: Parser<T>) -> Parser<T>
where
T: 'static,
{
let parse = move |mut i: Args| -> Result<(T, Args), Error> {
i.head = usize::MAX;
// To generate less confusing error messages give priority to the left most flag/argument
// from the command line:
// So if program accepts only one of 3 flags: -a, -b and -c and all 3 are present
// take the first one and reject the remaining ones.
let (res, new_args) = match ((self.parse)(i.clone()), (other.parse)(i)) {
// side channel (--help) reporting takes priority
(e @ Err(Error::Stdout(_)), _) | (_, e @ Err(Error::Stdout(_))) => e,
(Ok((r1, a1)), Ok((r2, a2))) => {
if a1.head < a2.head {
Ok((r1, a1))
} else {
Ok((r2, a2))
}
}
(Ok(ok), Err(_)) | (Err(_), Ok(ok)) => Ok(ok),
(Err(e1), Err(e2)) => Err(e1.combine_with(e2)),
}?;
Ok((res, new_args))
};
Parser {
parse: Rc::new(parse),
meta: self.meta.or(other.meta),
}
}
/// Fail with a fixed error message
/// ```rust
/// # use bpaf::*;
/// let a = short('a').switch();
/// let no_a = Parser::fail("Custom error message for missing -a");
///
/// // Parser will produce a custom error message if `-a` is not specified
/// let a_: Parser<bool> = a.or_else(no_a);
/// # drop(a_);
/// ```
#[must_use]
pub fn fail<M>(msg: M) -> Parser<T>
where
String: From<M>,
M: Clone + 'static,
{
Parser {
meta: Meta::Empty,
parse: Rc::new(move |_| Err(Error::Stderr(String::from(msg.clone())))),
}
}
/// Consume zero or more items from a command line
///
/// ```rust
/// # use bpaf::*;
/// // parser will accept multiple `-n` arguments:
/// // `-n 1, -n 2, -n 3`
/// // and return all of them as a vector which can be empty if no `-n` specified
/// let n: Parser<Vec<u32>> = short('n').argument("NUM").from_str::<u32>().many();
/// # drop(n);
/// ```
///
/// # Panics
/// Panics if parser succeeds without consuming any input: any parser modified with
/// `many` must consume something,
#[must_use]
pub fn many(self) -> Parser<Vec<T>>
where
T: 'static,
{
let parse = move |mut i: Args| {
let mut res = Vec::new();
let mut size = i.len();
while let Ok((elt, new_i)) = (self.parse)(i.clone()) {
let new_size = new_i.len();
#[allow(clippy::panic)]
if new_size < size {
size = new_size;
} else {
panic!("many can't be used with non failing parser")
}
i = new_i;
res.push(elt);
}
Ok((res, i))
};
Parser {
parse: Rc::new(parse),
meta: self.meta.many(),
}
}
/// Validate or fail with a message
///
/// ```rust
/// # use bpaf::*;
/// let n = short('n').argument("NUM").from_str::<u32>();
/// // Parser will reject values greater than 10
/// let n = n.guard(|v| *v <= 10, "Values greater than 10 are only available in the DLC pack!");
/// # drop(n);
/// ```
#[must_use]
pub fn guard<F>(self, m: F, message: &'static str) -> Parser<T>
where
F: Fn(&T) -> bool + 'static,
T: 'static,
{
let parse = move |i: Args| match (self.parse)(i) {
Ok((ok, i)) if m(&ok) => Ok((ok, i)),
Ok(_) => Err(Error::Stderr(message.to_owned())), // TODO - see what exactly we tried to parse
Err(err) => Err(err),
};
Parser {
parse: Rc::new(parse),
meta: self.meta,
}
}
/// Consume one or more items from a command line
///
/// Takes a string literal that will be used as an
/// error message if there's not enough parameters specified
///
/// ```rust
/// # use bpaf::*;
/// // parser will accept multiple `-n` arguments:
/// // `-n 1, -n 2, -n 3`
/// // and return all of them as a vector. At least one `-n` argument is required.
/// let n: Parser<Vec<u32>> = short('n').argument("NUM")
/// .from_str::<u32>().some("You need to specify at least one number");
/// # drop(n);
/// ```
#[must_use]
pub fn some(self, msg: &'static str) -> Parser<Vec<T>>
where
T: 'static,
{
self.many().guard(|x| !x.is_empty(), msg)
}
/// Turn a required parser into optional
///
/// ```rust
/// # use bpaf::*;
/// let n: Parser<u32> = short('n').argument("NUM").from_str();
/// // if `-n` is not specified - parser will return `None`
/// let n: Parser<Option<u32>> = n.optional();
/// # drop(n);
/// ```
pub fn optional(self) -> Parser<Option<T>>
where
T: 'static + Clone,
{
self.map(Some).fallback(None)
}
/// Apply a pure transformation to a contained value
///
/// ```rust
/// # use bpaf::*;
/// let n: Parser<u32> = short('n').argument("NUM").from_str();
/// // produced value is now twice as large
/// let n = n.map(|v| v * 2);
/// # drop(n);
/// ```
pub fn map<F, B>(self, map: F) -> Parser<B>
where
F: Fn(T) -> B + 'static,
T: 'static,
{
let parse = move |args: Args| {
let (t, args) = (self.parse)(args)?;
Ok((map(t), args))
};
Parser {
parse: Rc::new(parse),
meta: self.meta,
}
}
/// Apply a failing transformation
///
/// See also [`from_str`][Parser::from_str]
/// ```rust
/// # use bpaf::*;
/// let s: Parser<String> = short('n').argument("NUM");
/// // Try to parse String into u32 or fail during the parsing
/// use std::str::FromStr;
/// let n = s.map(|s| u32::from_str(&s));
/// # drop(n);
/// ```
pub fn parse<F, B, E>(self, map: F) -> Parser<B>
where
F: Fn(T) -> Result<B, E> + 'static,
T: 'static,
E: ToString,
{
let parse = move |args: Args| {
let (t, args) = (self.parse)(args)?;
match map(t) {
Ok(ok) => Ok((ok, args)),
Err(e) => Err(Error::Stderr(
if let Some(Word { utf8: Some(w), .. }) = args.current {
format!("Couldn't parse {:?}: {}", w, e.to_string())
} else {
format!("Couldn't parse: {}", e.to_string())
},
)),
}
};
Parser {
parse: Rc::new(parse),
meta: self.meta,
}
}
/// Use this value as default if value is not present on a command line
///
/// Would still fail if value is present but failure comes from some transformation
/// ```rust
/// # use bpaf::*;
/// let n = short('n').argument("NUM").from_str::<u32>().fallback(42);
/// # drop(n)
/// ```
#[must_use]
pub fn fallback(self, val: T) -> Parser<T>
where
T: Clone + 'static,
{
let parse = move |i: Args| match (self.parse)(i.clone()) {
Ok(ok) => Ok(ok),
e @ Err(Error::Stderr(_)) => e,
Err(_) => Ok((val.clone(), i)),
};
Parser {
parse: Rc::new(parse),
meta: Meta::optional(self.meta),
}
}
/// Use value produced by this function as default if value is not present
///
/// Would still fail if value is present but failure comes from some transformation
/// ```rust
/// # use bpaf::*;
/// let n = short('n').argument("NUM").from_str::<u32>();
/// let n = n.fallback_with(|| Result::<u32, String>::Ok(42));
/// # drop(n)
/// ```
#[must_use]
pub fn fallback_with<F, E>(self, val: F) -> Parser<T>
where
F: Fn() -> Result<T, E> + Clone + 'static,
E: ToString,
T: Clone + 'static,
{
let parse = move |i: Args| match (self.parse)(i.clone()) {
Ok(ok) => Ok(ok),
e @ Err(Error::Stderr(_)) => e,
Err(_) => match val() {
Ok(ok) => Ok((ok, i)),
Err(e) => Err(Error::Stderr(e.to_string())),
},
};
Parser {
parse: Rc::new(parse),
meta: Meta::optional(self.meta),
}
}
/// Parse `T` or fallback to `T::default()`
///
/// ```rust
/// # use bpaf::*;
/// let n = short('n').argument("NUM").from_str::<u32>().default();
/// # drop(n)
/// ```
#[must_use]
pub fn default(self) -> Parser<T>
where
T: Default + 'static + Clone,
{
self.fallback(T::default())
}
/// Attach help message to a complex parser
///
/// ```rust
/// # use bpaf::*;
/// let width = short('w').argument("PX").from_str::<u32>();
/// let height = short('h').argument("PX").from_str::<u32>();
/// let rect = construct!(width, height).group_help("take a rectangle");
/// # drop(rect);
/// ```
/// See `examples/rectangle.rs` for a complete example
#[must_use]
pub fn group_help(self, msg: &'static str) -> Parser<T> {
Self {
parse: self.parse,
meta: Meta::decorate(self.meta, msg),
}
}
/// Ignore this parser during any sort of help generation
///
/// Best used for optional parsers or parsers with a defined fallback
///
/// ```rust
/// # use bpaf::*;
/// // bpaf will accept `-w` but won't show it during help generation
/// let width = short('w').argument("PX").from_str::<u32>().fallback(10).hide();
/// let height = short('h').argument("PX").from_str::<u32>();
/// let rect = construct!(width, height);
/// # drop(rect);
/// ```
///
/// See also `examples/cargo-cmd.rs`
#[must_use]
pub fn hide(self) -> Parser<T>
where
T: 'static,
{
Self {
parse: Rc::new(move |args: Args| {
(self.parse)(args).map_err(|_| Error::Missing(Vec::new()))
}),
meta: Meta::Id,
}
}
}
impl Parser<String> {
/// Parse stored [`String`] using [`FromStr`] instance
///
/// ```rust
/// # use bpaf::*;
/// let speed = short('s').argument("SPEED").from_str::<f64>();
/// // at this point program would accept things like "-s 3.1415"
/// // but reject "-s pi"
/// # drop(speed)
/// ```
#[must_use]
pub fn from_str<T>(self) -> Parser<T>
where
T: FromStr,
<T as FromStr>::Err: std::fmt::Display,
{
self.parse(|s| T::from_str(&s))
}
}
/// Unsuccessful command line parsing outcome
///
/// Useful for unit testing for user parsers, intented to
/// be consumed with [`ParseFailure::unwrap_stdout`] and [`ParseFailure::unwrap_stdout`]
#[derive(Clone, Debug)]
pub enum ParseFailure {
/// Terminate and print this to stdout
Stdout(String),
/// Terminate and print this to stderr
Stderr(String),
}
impl ParseFailure {
/// Returns the contained `stderr` values
///
/// Intended to be used with unit tests
///
/// # Panics
///
/// Will panic if failure contains `stdout`
#[allow(clippy::must_use_candidate)]
pub fn unwrap_stderr(self) -> String {
match self {
Self::Stderr(err) => err,
Self::Stdout(_) => {
panic!("not an stderr: {:?}", self)
}
}
}
/// Returns the contained `stdout` values
///
/// Intended to be used with unit tests
///
/// # Panics
///
/// Will panic if failure contains `stderr`
#[allow(clippy::must_use_candidate)]
pub fn unwrap_stdout(self) -> String {
match self {
Self::Stdout(err) => err,
Self::Stderr(_) => {
panic!("not an stdout: {:?}", self)
}
}
}
}
impl<T> OptionParser<T> {
/// Execute the [`OptionParser`], extract a parsed value or print some diagnostic and exit
///
/// ```no_run
/// # use bpaf::*;
/// let verbose = short('v').req_flag(()).many().map(|xs|xs.len());
/// let info = Info::default().descr("Takes verbosity flag and does nothing else");
///
/// let opt = info.for_parser(verbose).run();
/// // At this point `opt` contains number of repetitions of `-v` on a command line
/// # drop(opt)
/// ```
#[must_use]
pub fn run(self) -> T {
let mut pos_only = false;
let mut vec = Vec::new();
for arg in std::env::args_os().skip(1) {
args::push_vec(&mut vec, arg, &mut pos_only);
}
match self.run_inner(Args::from(vec)) {
Ok(t) => t,
Err(ParseFailure::Stdout(msg)) => {
println!("{}", msg);
std::process::exit(0);
}
Err(ParseFailure::Stderr(msg)) => {
eprintln!("{}", msg);
std::process::exit(1);
}
}
}
/// Execute the [`OptionParser`] and produce a value that can be used in unit tests
///
/// ```
/// #[test]
/// fn positional_argument() {
/// let p = positional("FILE").help("File to process");
/// let parser = Info::default().for_parser(p);
///
/// let help = parser
/// .run_inner(Args::from(&["--help"]))
/// .unwrap_err()
/// .unwrap_stdout();
/// let expected_help = "\
/// Usage: <FILE>
///
/// Available options:
/// -h, --help Prints help information
/// ";
/// assert_eq!(expected_help, help);
/// }
/// ```
///
/// See also [`Args`] and it's `From` impls to produce input and
/// [`ParseFailure::unwrap_stderr`] / [`ParseFailure::unwrap_stdout`] for processing results.
///
/// # Errors
///
/// If parser can't produce desired outcome `run_inner` will return [`ParseFailure`]
/// which represents runtime behavior: one branch to print something to stdout and exit with
/// success and the other branch to print something to stderr and exit with failure.
///
/// Parser is not really capturing anything. If parser detects `--help` or `--version` it will
/// always produce something that can be consumed with [`ParseFailure::unwrap_stdout`].
/// Otherwise it will produce [`ParseFailure::unwrap_stderr`] generated either by the parser
/// itself in case someone required field is missing or by user's [`Parser::guard`] or
/// [`Parser::parse`] functions.
///
/// API for those is constructed to only produce a [`String`]. If you try to print something inside
/// [`Parser::map`] or [`Parser::parse`] - it will not be captured. Depending on a test case
/// you'll know what to use: `unwrap_stdout` if you want to test generated help or `unwrap_stderr`
/// if you are testing `parse` / `guard` / missing parameters.
///
/// Exact string reperentations may change between versions including minor releases.
pub fn run_inner(self, args: Args) -> Result<T, ParseFailure> {
match (self.parse)(args) {
Ok((t, rest)) if rest.is_empty() => Ok(t),
Ok((_, rest)) => Err(ParseFailure::Stderr(format!("unexpected {:?}", rest))),
Err(Error::Missing(metas)) => Err(ParseFailure::Stderr(format!(
"Expected {}, pass --help for usage information",
Meta::Or(metas)
))),
Err(Error::Stdout(stdout)) => Err(ParseFailure::Stdout(stdout)),
Err(Error::Stderr(stderr)) => Err(ParseFailure::Stderr(stderr)),
}
}
}
/// Strip a command name if present at the front when used as a cargo command
///
/// This helper should be used on a top level parser
///
/// ```rust
/// # use bpaf::*;
/// let width = short('w').argument("PX").from_str::<u32>();
/// let height = short('h').argument("PX").from_str::<u32>();
/// let parser: Parser<(u32, u32)> = cargo_helper("cmd", construct!(width, height));
/// # drop(parser);
/// ```
#[must_use]
pub fn cargo_helper<T>(cmd: &'static str, parser: Parser<T>) -> Parser<T>
where
T: 'static,
{
let skip = positional_if("", move |s| cmd == s).optional().hide();
construct!(skip, parser).map(|x| x.1)
}