feat: split engine into crates

2 files changed, 180 insertions, 0 deletions

diff --git a/crates/brainf_lexer/src/lexer.rs b/crates/brainf_lexer/src/lexer.rs
new file mode 100644
index 0000000..b95cd87
--- /dev/null
+++ b/crates/brainf_lexer/src/lexer.rs
@@ -0,0 +1,75 @@
+//! Lexer implementation using logos.
+
+#![expect(clippy::indexing_slicing)]
+
+use logos::{Lexer, Logos};
+
+/// List of operator codes for the lexer
+/// Note: Any input symbol that is not in this list is a comment
+
+fn loop_callback(lex: &Lexer<Token>) -> (usize, usize) {
+	let span = lex.span();
+
+	(span.start, span.len())
+}
+
+/// List of Tokens for the lexer
+/// Note: Any input symbol that is not in this list is a comment
+#[derive(Clone, Copy, Debug, Logos, PartialEq, Eq)]
+#[logos(skip r"[^<>+\-.,\[\]]+")]
+pub enum Token {
+	/// `>`
+	///
+	/// Increment the data pointer by one (to point to the next cell to the
+	/// right).
+	#[token(">")]
+	IncrementPointer,
+
+	/// `<`
+	///
+	/// Decrement the data pointer by one (to point to the next cell to the
+	/// left).
+	#[token("<")]
+	DecrementPointer,
+
+	/// `+`
+	///
+	/// Increment the byte at the data pointer by one.
+	#[token("+")]
+	IncrementByte,
+
+	/// `-`
+	///
+	/// Decrement the byte at the data pointer by one.
+	#[token("-")]
+	DecrementByte,
+
+	/// `.`
+	///
+	/// Output the byte at the data pointer.
+	#[token(".")]
+	OutputByte,
+
+	/// `,`
+	///
+	/// Accept one byte of input, storing its value in the byte at the data
+	/// pointer.
+	#[token(",")]
+	InputByte,
+
+	/// `[`
+	///
+	/// If the byte at the data pointer is zero, then instead of moving the
+	/// instruction pointer forward to the next command, jump it forward to the
+	/// command after the matching ] command.
+	#[token("[", loop_callback)]
+	StartLoop((usize, usize)),
+
+	/// `]`
+	///
+	/// If the byte at the data pointer is nonzero, then instead of moving the
+	/// instruction pointer forward to the next command, jump it back to the
+	/// command after the matching [ command.
+	#[token("]", loop_callback)]
+	EndLoop((usize, usize)),
+}
diff --git a/crates/brainf_lexer/src/lib.rs b/crates/brainf_lexer/src/lib.rs
new file mode 100644
index 0000000..7f6e5be
--- /dev/null
+++ b/crates/brainf_lexer/src/lib.rs
@@ -0,0 +1,105 @@
+#![feature(lint_reasons)]
+#![deny(clippy::complexity)]
+#![deny(clippy::nursery)]
+#![deny(clippy::pedantic)]
+#![deny(clippy::perf)]
+#![deny(clippy::suspicious)]
+#![deny(clippy::alloc_instead_of_core)]
+#![deny(clippy::as_underscore)]
+#![deny(clippy::clone_on_ref_ptr)]
+#![deny(clippy::create_dir)]
+#![warn(clippy::dbg_macro)]
+#![deny(clippy::default_numeric_fallback)]
+#![deny(clippy::default_union_representation)]
+#![deny(clippy::deref_by_slicing)]
+#![deny(clippy::empty_structs_with_brackets)]
+#![deny(clippy::exit)]
+#![deny(clippy::expect_used)]
+#![deny(clippy::filetype_is_file)]
+#![deny(clippy::fn_to_numeric_cast)]
+#![deny(clippy::format_push_string)]
+#![deny(clippy::get_unwrap)]
+#![deny(clippy::if_then_some_else_none)]
+#![allow(
+	clippy::implicit_return,
+	reason = "returns should be done implicitly, not explicitly"
+)]
+#![deny(clippy::indexing_slicing)]
+#![deny(clippy::large_include_file)]
+#![deny(clippy::let_underscore_must_use)]
+#![deny(clippy::lossy_float_literal)]
+#![deny(clippy::map_err_ignore)]
+#![deny(clippy::mem_forget)]
+#![deny(clippy::missing_docs_in_private_items)]
+#![deny(clippy::missing_trait_methods)]
+#![deny(clippy::mod_module_files)]
+#![deny(clippy::multiple_inherent_impl)]
+#![deny(clippy::mutex_atomic)]
+#![deny(clippy::needless_return)]
+#![deny(clippy::non_ascii_literal)]
+#![deny(clippy::panic_in_result_fn)]
+#![deny(clippy::pattern_type_mismatch)]
+#![deny(clippy::rc_buffer)]
+#![deny(clippy::rc_mutex)]
+#![deny(clippy::rest_pat_in_fully_bound_structs)]
+#![deny(clippy::same_name_method)]
+#![deny(clippy::separated_literal_suffix)]
+#![deny(clippy::str_to_string)]
+#![deny(clippy::string_add)]
+#![deny(clippy::string_slice)]
+#![deny(clippy::string_to_string)]
+#![allow(
+	clippy::tabs_in_doc_comments,
+	reason = "tabs are preferred for this project"
+)]
+#![deny(clippy::try_err)]
+#![deny(clippy::undocumented_unsafe_blocks)]
+#![deny(clippy::unnecessary_self_imports)]
+#![deny(clippy::unneeded_field_pattern)]
+#![deny(clippy::unwrap_in_result)]
+#![deny(clippy::unwrap_used)]
+#![warn(clippy::use_debug)]
+#![deny(clippy::verbose_file_reads)]
+#![deny(clippy::wildcard_dependencies)]
+#![deny(clippy::wildcard_enum_match_arm)]
+#![deny(missing_copy_implementations)]
+#![deny(missing_debug_implementations)]
+#![deny(missing_docs)]
+#![deny(single_use_lifetimes)]
+#![deny(unsafe_code)]
+#![deny(unused)]
+
+//! # `brainf_lexer`
+//!
+//! Implementation of a Brainfuck lexer in Rust.
+
+mod lexer;
+
+pub use lexer::Token;
+use logos::Logos;
+use thiserror::Error;
+
+/// Error type for lexer.
+#[derive(Clone, Copy, Debug, Error)]
+pub enum Error {
+	/// Logos was unable to lex part of the input.
+	#[error("lexer was unable to lex input")]
+	LexingError,
+}
+
+/// Lexes the Brainfuck input, returning a Vec of Tokens.
+///
+/// # Errors
+///
+/// This function will return an error if the lexer is unable to lex one or more
+/// of the input characters.
+pub fn lex(input: &str) -> Result<Vec<Token>, Error> {
+	lexer::Token::lexer(input).try_fold(Vec::new(), |mut arr, result| {
+		result
+			.map_or(Err(()), |token| {
+				arr.push(token);
+				Ok(arr)
+			})
+			.map_err(|_err| Error::LexingError)
+	})
+}