nalgebra/nalgebra-macros/src/lib.rs

325 lines
10 KiB
Rust

//! Macros for `nalgebra`.
//!
//! This crate is not intended for direct consumption. Instead, the macros are re-exported by
//! `nalgebra` if the `macros` feature is enabled (enabled by default).
#![deny(
nonstandard_style,
unused,
missing_docs,
rust_2018_idioms,
rust_2018_compatibility,
future_incompatible,
missing_copy_implementations,
missing_debug_implementations,
clippy::all,
clippy::pedantic
)]
use proc_macro::TokenStream;
use quote::{quote, ToTokens, TokenStreamExt};
use syn::parse::{Error, Parse, ParseStream, Result};
use syn::punctuated::Punctuated;
use syn::Expr;
use syn::{parse_macro_input, Token};
use proc_macro2::{Delimiter, Spacing, TokenStream as TokenStream2, TokenTree};
use proc_macro2::{Group, Punct};
struct Matrix {
// Represent the matrix as a row-major vector of vectors of expressions
rows: Vec<Vec<Expr>>,
ncols: usize,
}
impl Matrix {
fn nrows(&self) -> usize {
self.rows.len()
}
fn ncols(&self) -> usize {
self.ncols
}
/// Produces a stream of tokens representing this matrix as a column-major nested array.
fn to_col_major_nested_array_tokens(&self) -> TokenStream2 {
let mut result = TokenStream2::new();
for j in 0..self.ncols() {
let mut col = TokenStream2::new();
let col_iter = (0..self.nrows()).map(move |i| &self.rows[i][j]);
col.append_separated(col_iter, Punct::new(',', Spacing::Alone));
result.append(Group::new(Delimiter::Bracket, col));
result.append(Punct::new(',', Spacing::Alone));
}
TokenStream2::from(TokenTree::Group(Group::new(Delimiter::Bracket, result)))
}
/// Produces a stream of tokens representing this matrix as a column-major flat array
/// (suitable for representing e.g. a `DMatrix`).
fn to_col_major_flat_array_tokens(&self) -> TokenStream2 {
let mut data = TokenStream2::new();
for j in 0..self.ncols() {
for i in 0..self.nrows() {
self.rows[i][j].to_tokens(&mut data);
data.append(Punct::new(',', Spacing::Alone));
}
}
TokenStream2::from(TokenTree::Group(Group::new(Delimiter::Bracket, data)))
}
}
type MatrixRowSyntax = Punctuated<Expr, Token![,]>;
impl Parse for Matrix {
fn parse(input: ParseStream<'_>) -> Result<Self> {
let mut rows = Vec::new();
let mut ncols = None;
while !input.is_empty() {
let row_span = input.span();
let row = MatrixRowSyntax::parse_separated_nonempty(input)?;
if let Some(ncols) = ncols {
if row.len() != ncols {
let row_idx = rows.len();
let error_msg = format!(
"Unexpected number of entries in row {}. Expected {}, found {} entries.",
row_idx,
ncols,
row.len()
);
return Err(Error::new(row_span, error_msg));
}
} else {
ncols = Some(row.len());
}
rows.push(row.into_iter().collect());
// We've just read a row, so if there are more tokens, there must be a semi-colon,
// otherwise the input is malformed
if !input.is_empty() {
input.parse::<Token![;]>()?;
}
}
Ok(Self {
rows,
ncols: ncols.unwrap_or(0),
})
}
}
/// Construct a fixed-size matrix directly from data.
///
/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
///
/// This macro facilitates easy construction of matrices when the entries of the matrix are known
/// (either as constants or expressions). This macro produces an instance of `SMatrix`. This means
/// that the data of the matrix is stored on the stack, and its dimensions are fixed at
/// compile-time. If you want to construct a dynamic matrix, use [`dmatrix!`] instead.
///
/// `matrix!` is intended to be both the simplest and most efficient way to construct (small)
/// matrices, and can also be used in *const fn* contexts.
///
/// The syntax is MATLAB-like. Column elements are separated by a comma (`,`), and a semi-colon
/// (`;`) designates that a new row begins.
///
/// # Examples
///
/// ```
/// use nalgebra::matrix;
///
/// // Produces a Matrix3<_> == SMatrix<_, 3, 3>
/// let a = matrix![1, 2, 3;
/// 4, 5, 6;
/// 7, 8, 9];
/// ```
///
/// You can construct matrices with arbitrary expressions for its elements:
///
/// ```
/// use nalgebra::{matrix, Matrix2};
/// let theta = 0.45f64;
///
/// let r = matrix![theta.cos(), - theta.sin();
/// theta.sin(), theta.cos()];
/// ```
#[proc_macro]
pub fn matrix(stream: TokenStream) -> TokenStream {
let matrix = parse_macro_input!(stream as Matrix);
let row_dim = matrix.nrows();
let col_dim = matrix.ncols();
let array_tokens = matrix.to_col_major_nested_array_tokens();
// TODO: Use quote_spanned instead??
let output = quote! {
nalgebra::SMatrix::<_, #row_dim, #col_dim>
::from_array_storage(nalgebra::ArrayStorage(#array_tokens))
};
proc_macro::TokenStream::from(output)
}
/// Construct a dynamic matrix directly from data.
///
/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
///
/// The syntax is exactly the same as for [`matrix!`], but instead of producing instances of
/// `SMatrix`, it produces instances of `DMatrix`. At the moment it is not usable
/// in `const fn` contexts.
///
/// ```
/// use nalgebra::dmatrix;
///
/// // Produces a DMatrix<_>
/// let a = dmatrix![1, 2, 3;
/// 4, 5, 6;
/// 7, 8, 9];
/// ```
#[proc_macro]
pub fn dmatrix(stream: TokenStream) -> TokenStream {
let matrix = parse_macro_input!(stream as Matrix);
let row_dim = matrix.nrows();
let col_dim = matrix.ncols();
let array_tokens = matrix.to_col_major_flat_array_tokens();
// TODO: Use quote_spanned instead??
let output = quote! {
nalgebra::DMatrix::<_>
::from_vec_storage(nalgebra::VecStorage::new(
nalgebra::Dynamic::new(#row_dim),
nalgebra::Dynamic::new(#col_dim),
vec!#array_tokens))
};
proc_macro::TokenStream::from(output)
}
struct Vector {
elements: Vec<Expr>,
}
impl Vector {
fn to_array_tokens(&self) -> TokenStream2 {
let mut data = TokenStream2::new();
data.append_separated(&self.elements, Punct::new(',', Spacing::Alone));
TokenStream2::from(TokenTree::Group(Group::new(Delimiter::Bracket, data)))
}
fn len(&self) -> usize {
self.elements.len()
}
}
impl Parse for Vector {
fn parse(input: ParseStream<'_>) -> Result<Self> {
// The syntax of a vector is just the syntax of a single matrix row
if input.is_empty() {
Ok(Self {
elements: Vec::new(),
})
} else {
let elements = MatrixRowSyntax::parse_separated_nonempty(input)?
.into_iter()
.collect();
Ok(Self { elements })
}
}
}
/// Construct a fixed-size column vector directly from data.
///
/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
///
/// Similarly to [`matrix!`], this macro facilitates easy construction of fixed-size vectors.
/// However, whereas the [`matrix!`] macro expects each row to be separated by a semi-colon,
/// the syntax of this macro is instead similar to `vec!`, in that the elements of the vector
/// are simply listed consecutively.
///
/// `vector!` is intended to be the most readable and performant way of constructing small,
/// fixed-size vectors, and it is usable in `const fn` contexts.
///
/// ## Examples
///
/// ```
/// use nalgebra::vector;
///
/// // Produces a Vector3<_> == SVector<_, 3>
/// let v = vector![1, 2, 3];
/// ```
#[proc_macro]
pub fn vector(stream: TokenStream) -> TokenStream {
let vector = parse_macro_input!(stream as Vector);
let len = vector.len();
let array_tokens = vector.to_array_tokens();
let output = quote! {
nalgebra::SVector::<_, #len>
::from_array_storage(nalgebra::ArrayStorage([#array_tokens]))
};
proc_macro::TokenStream::from(output)
}
/// Construct a dynamic column vector directly from data.
///
/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
///
/// The syntax is exactly the same as for [`vector!`], but instead of producing instances of
/// `SVector`, it produces instances of `DVector`. At the moment it is not usable
/// in `const fn` contexts.
///
/// ```
/// use nalgebra::dvector;
///
/// // Produces a DVector<_>
/// let v = dvector![1, 2, 3];
/// ```
#[proc_macro]
pub fn dvector(stream: TokenStream) -> TokenStream {
let vector = parse_macro_input!(stream as Vector);
let len = vector.len();
let array_tokens = vector.to_array_tokens();
let output = quote! {
nalgebra::DVector::<_>
::from_vec_storage(nalgebra::VecStorage::new(
nalgebra::Dynamic::new(#len),
nalgebra::Const::<1>,
vec!#array_tokens))
};
proc_macro::TokenStream::from(output)
}
/// Construct a fixed-size point directly from data.
///
/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
///
/// Similarly to [`vector!`], this macro facilitates easy construction of points.
///
/// `point!` is intended to be the most readable and performant way of constructing small,
/// points, and it is usable in `const fn` contexts.
///
/// ## Examples
///
/// ```
/// use nalgebra::point;
///
/// // Produces a Point3<_>
/// let v = point![1, 2, 3];
/// ```
#[proc_macro]
pub fn point(stream: TokenStream) -> TokenStream {
let vector = parse_macro_input!(stream as Vector);
let len = vector.len();
let array_tokens = vector.to_array_tokens();
let output = quote! {
nalgebra::Point::<_, #len> {
coords: nalgebra::SVector::<_, #len>
::from_array_storage(nalgebra::ArrayStorage([#array_tokens]))
}
};
proc_macro::TokenStream::from(output)
}