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|
/// `mbe` (short for Macro By Example) crate contains code for handling
/// `macro_rules` macros. It uses `TokenTree` (from `ra_tt` package) as the
/// interface, although it contains some code to bridge `SyntaxNode`s and
/// `TokenTree`s as well!
macro_rules! impl_froms {
($e:ident: $($v:ident), *) => {
$(
impl From<$v> for $e {
fn from(it: $v) -> $e {
$e::$v(it)
}
}
)*
}
}
mod mbe_parser;
mod mbe_expander;
mod syntax_bridge;
mod tt_cursor;
mod subtree_source;
mod subtree_parser;
use ra_syntax::SmolStr;
use smallvec::SmallVec;
pub use tt::{Delimiter, Punct};
#[derive(Debug, PartialEq, Eq)]
pub enum ParseError {
Expected(String),
}
#[derive(Debug, PartialEq, Eq)]
pub enum ExpandError {
NoMatchingRule,
UnexpectedToken,
BindingError(String),
ConversionError,
}
pub use crate::syntax_bridge::{
ast_to_token_tree,
token_tree_to_ast_item_list,
syntax_node_to_token_tree,
token_tree_to_expr,
token_tree_to_pat,
token_tree_to_ty,
token_tree_to_macro_items,
token_tree_to_macro_stmts,
};
/// This struct contains AST for a single `macro_rules` definition. What might
/// be very confusing is that AST has almost exactly the same shape as
/// `tt::TokenTree`, but there's a crucial difference: in macro rules, `$ident`
/// and `$()*` have special meaning (see `Var` and `Repeat` data structures)
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct MacroRules {
pub(crate) rules: Vec<Rule>,
}
impl MacroRules {
pub fn parse(tt: &tt::Subtree) -> Result<MacroRules, ParseError> {
mbe_parser::parse(tt)
}
pub fn expand(&self, tt: &tt::Subtree) -> Result<tt::Subtree, ExpandError> {
mbe_expander::expand(self, tt)
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Rule {
pub(crate) lhs: Subtree,
pub(crate) rhs: Subtree,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) enum TokenTree {
Leaf(Leaf),
Subtree(Subtree),
Repeat(Repeat),
}
impl_froms!(TokenTree: Leaf, Subtree, Repeat);
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) enum Leaf {
Literal(Literal),
Punct(Punct),
Ident(Ident),
Var(Var),
}
impl_froms!(Leaf: Literal, Punct, Ident, Var);
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Subtree {
pub(crate) delimiter: Delimiter,
pub(crate) token_trees: Vec<TokenTree>,
}
#[derive(Clone, Debug, Eq)]
pub(crate) enum Separator {
Literal(tt::Literal),
Ident(tt::Ident),
Puncts(SmallVec<[tt::Punct; 3]>),
}
// Note that when we compare a Separator, we just care about its textual value.
impl PartialEq for crate::Separator {
fn eq(&self, other: &crate::Separator) -> bool {
use crate::Separator::*;
match (self, other) {
(Ident(ref a), Ident(ref b)) => a.text == b.text,
(Literal(ref a), Literal(ref b)) => a.text == b.text,
(Puncts(ref a), Puncts(ref b)) if a.len() == b.len() => {
let a_iter = a.iter().map(|a| a.char);
let b_iter = b.iter().map(|b| b.char);
a_iter.eq(b_iter)
}
_ => false,
}
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Repeat {
pub(crate) subtree: Subtree,
pub(crate) kind: RepeatKind,
pub(crate) separator: Option<Separator>,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) enum RepeatKind {
ZeroOrMore,
OneOrMore,
ZeroOrOne,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Literal {
pub(crate) text: SmolStr,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Ident {
pub(crate) text: SmolStr,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Var {
pub(crate) text: SmolStr,
pub(crate) kind: Option<SmolStr>,
}
#[cfg(test)]
mod tests;
|
