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#![allow(clippy::cognitive_complexity)]
#![allow(clippy::many_single_char_names)]
#![allow(clippy::needless_doctest_main)]
#![allow(clippy::new_without_default)]
#![allow(clippy::range_plus_one)]
#![allow(clippy::too_many_arguments)]
#![allow(clippy::type_complexity)]
#![allow(clippy::unnecessary_wraps)]
#![allow(clippy::upper_case_acronyms)]
//! `lrpar` provides a Yacc-compatible parser (where grammars can be generated at compile-time or
//! run-time). It can take in traditional `.y` files and convert them into an idiomatic Rust
//! parser.
//!
//! If you're new to `lrpar`, please read the "quick start guide". The "grmtools book" and API
//! reference have more detailed information. You can find the appropriate documentation for the
//! version of lrpar you are using here:
//!
//! | Latest release | master |
//! |-----------------------------------------|--------|
//! | [Quickstart guide](https://softdevteam.github.io/grmtools/latest_release/book/quickstart.html) | [Quickstart guide](https://softdevteam.github.io/grmtools/master/book/quickstart.html) |
//! | [grmtools book](https://softdevteam.github.io/grmtools/latest_release/book/) | [grmtools book](https://softdevteam.github.io/grmtools/master/book) |
//! | [lrpar API](https://docs.rs/lrpar/) | [lrpar API](https://softdevteam.github.io/grmtools/master/api/lrpar/) |
//!
//! [Documentation for all past and present releases](https://softdevteam.github.io/grmtools/)
//!
//!
//! ## Example
//!
//! Let's assume we want to statically generate a parser for a simple calculator language (and
//! let's also assume we are able to use [`lrlex`](https://crates.io/crates/lrlex) for the lexer).
//! We need to add a `build.rs` file to our project which statically compiles both the lexer and
//! parser. While we can perform both steps individually, it's easiest to use `lrlex` which does
//! both jobs for us in one go. Our `build.rs` file thus looks as follows:
//!
//! ```text
//! use cfgrammar::yacc::YaccKind;
//! use lrlex::CTLexerBuilder;
//!
//! fn main() -> Result<(), Box<dyn std::error::Error>> {
//! CTLexerBuilder::new()
//! .lrpar_config(|ctp| {
//! ctp.yacckind(YaccKind::Grmtools)
//! .grammar_in_src_dir("calc.y")
//! .unwrap()
//! })
//! .lexer_in_src_dir("calc.l")?
//! .build()?;
//! Ok(())
//! }
//! ```
//!
//! where `src/calc.l` is as follows:
//!
//! ```text
//! %%
//! [0-9]+ "INT"
//! \+ "+"
//! \* "*"
//! \( "("
//! \) ")"
//! [\t ]+ ;
//! ```
//!
//! and `src/calc.y` is as follows:
//!
//! ```text
//! %start Expr
//! %avoid_insert "INT"
//! %%
//! Expr -> Result<u64, ()>:
//! Expr '+' Term { Ok($1? + $3?) }
//! | Term { $1 }
//! ;
//!
//! Term -> Result<u64, ()>:
//! Term '*' Factor { Ok($1? * $3?) }
//! | Factor { $1 }
//! ;
//!
//! Factor -> Result<u64, ()>:
//! '(' Expr ')' { $2 }
//! | 'INT'
//! {
//! let v = $1.map_err(|_| ())?;
//! parse_int($lexer.span_str(v.span()))
//! }
//! ;
//! %%
//! // Any functions here are in scope for all the grammar actions above.
//!
//! fn parse_int(s: &str) -> Result<u64, ()> {
//! match s.parse::<u64>() {
//! Ok(val) => Ok(val),
//! Err(_) => {
//! eprintln!("{} cannot be represented as a u64", s);
//! Err(())
//! }
//! }
//! }
//! ```
//!
//! Because we specified that our Yacc file is in `Grmtools` format, each rule has a
//! separate Rust type to which all its functions conform (in this case, all the
//! rules have the same type, but that's not a requirement).
//!
//! A simple `src/main.rs` is as follows:
//!
//! ```text
//! use std::io::{self, BufRead, Write};
//!
//! use lrlex::lrlex_mod;
//! use lrpar::lrpar_mod;
//!
//! // Using `lrlex_mod!` brings the lexer for `calc.l` into scope. By default the module name
//! // will be `calc_l` (i.e. the file name, minus any extensions, with a suffix of `_l`).
//! lrlex_mod!("calc.l");
//! // Using `lrpar_mod!` brings the parser for `calc.y` into scope. By default the module name
//! // will be `calc_y` (i.e. the file name, minus any extensions, with a suffix of `_y`).
//! lrpar_mod!("calc.y");
//!
//! fn main() {
//! // Get the `LexerDef` for the `calc` language.
//! let lexerdef = calc_l::lexerdef();
//! let stdin = io::stdin();
//! loop {
//! print!(">>> ");
//! io::stdout().flush().ok();
//! match stdin.lock().lines().next() {
//! Some(Ok(ref l)) => {
//! if l.trim().is_empty() {
//! continue;
//! }
//! // Now we create a lexer with the `lexer` method with which we can lex an input.
//! let lexer = lexerdef.lexer(l);
//! // Pass the lexer to the parser and lex and parse the input.
//! let (res, errs) = calc_y::parse(&lexer);
//! for e in errs {
//! println!("{}", e.pp(&lexer, &calc_y::token_epp));
//! }
//! match res {
//! Some(Ok(r)) => println!("Result: {}", r),
//! _ => eprintln!("Unable to evaluate expression.")
//! }
//! }
//! _ => break
//! }
//! }
//! }
//! ```
//!
//! We can now `cargo run` our project and evaluate simple expressions:
//!
//! ```text
//! >>> 2 + 3
//! Result: 5
//! >>> 2 + 3 * 4
//! Result: 14
//! >>> (2 + 3) * 4
//! Result: 20
//! ```
//!
//! `lrpar` also comes with advanced [error
//! recovery](https://softdevteam.github.io/grmtools/master/book/errorrecovery.html) built-in:
//!
//! ```text
//! >>> 2 + + 3
//! Parsing error at line 1 column 5. Repair sequences found:
//! 1: Delete +
//! 2: Insert INT
//! Result: 5
//! >>> 2 + 3 3
//! Parsing error at line 1 column 7. Repair sequences found:
//! 1: Insert *
//! 2: Insert +
//! 3: Delete 3
//! Result: 11
//! >>> 2 + 3 4 5
//! Parsing error at line 1 column 7. Repair sequences found:
//! 1: Insert *, Delete 4
//! 2: Insert +, Delete 4
//! 3: Delete 4, Delete 5
//! 4: Insert +, Shift 4, Delete 5
//! 5: Insert +, Shift 4, Insert +
//! 6: Insert *, Shift 4, Delete 5
//! 7: Insert *, Shift 4, Insert *
//! 8: Insert *, Shift 4, Insert +
//! 9: Insert +, Shift 4, Insert *
//! Result: 17
//! ```
mod cpctplus;
#[doc(hidden)]
pub mod ctbuilder;
mod dijkstra;
#[doc(hidden)]
pub mod lex_api;
#[doc(hidden)]
pub mod parser;
#[cfg(test)]
mod test_utils;
pub use crate::{
ctbuilder::{CTParser, CTParserBuilder, Visibility},
lex_api::{LexError, Lexeme, Lexer, NonStreamingLexer},
parser::{LexParseError, Node, ParseError, ParseRepair, RTParserBuilder, RecoveryKind},
};
/// A convenience macro for including statically compiled `.y` files. A file `src/a/b/c.ly
/// processed by [CTParserBuilder::parser_in_src_dir] can then be used in a crate with
/// `lrpar_mod!("a/b/c.l")`.
///
/// Note that you can use `lrpar_mod` with [CTParserBuilder::output_path] if, and only if, the
/// output file was placed in [std::env::var]`("OUT_DIR")` or one of its subdirectories.
#[macro_export]
macro_rules! lrpar_mod {
($path:expr) => {
include!(concat!(env!("OUT_DIR"), "/", $path, ".rs"));
};
}
/// A `Span` records what portion of the user's input something (e.g. a lexeme or production)
/// references (i.e. the `Span` doesn't hold a reference / copy of the actual input).
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct Span {
start: usize,
end: usize,
}
impl Span {
/// Create a new span starting at byte `start` and ending at byte `end`.
///
/// # Panics
///
/// If `end` is less than `start`.
pub fn new(start: usize, end: usize) -> Self {
if end < start {
panic!("Span starts ({}) after it ends ({})!", start, end);
}
Span { start, end }
}
/// Byte offset of the start of the span.
pub fn start(&self) -> usize {
self.start
}
/// Byte offset of the end of the span.
pub fn end(&self) -> usize {
self.end
}
/// Length in bytes of the span.
pub fn len(&self) -> usize {
self.end - self.start
}
/// Returns `true` if this `Span` covers 0 bytes, or `false` otherwise.
pub fn is_empty(&self) -> bool {
self.len() == 0
}
}