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|
//! Syntax highlighting for macro_rules!.
use syntax::{SyntaxElement, SyntaxKind, SyntaxToken, TextRange, T};
use crate::{HighlightTag, HighlightedRange};
pub(super) struct MacroRulesHighlighter {
state: Option<MacroMatcherParseState>,
}
impl MacroRulesHighlighter {
pub(super) fn new() -> Self {
MacroRulesHighlighter { state: None }
}
pub(super) fn init(&mut self) {
self.state = Some(MacroMatcherParseState::new());
}
pub(super) fn reset(&mut self) {
self.state = None;
}
pub(super) fn advance(&mut self, token: &SyntaxToken) {
if let Some(state) = self.state.as_mut() {
update_macro_rules_state(state, token);
}
}
pub(super) fn highlight(&self, element: SyntaxElement) -> Option<HighlightedRange> {
if let Some(state) = self.state.as_ref() {
if matches!(state.rule_state, RuleState::Matcher | RuleState::Expander) {
if let Some(range) = is_metavariable(element) {
return Some(HighlightedRange {
range,
highlight: HighlightTag::UnresolvedReference.into(),
binding_hash: None,
});
}
}
}
None
}
}
struct MacroMatcherParseState {
/// Opening and corresponding closing bracket of the matcher or expander of the current rule
paren_ty: Option<(SyntaxKind, SyntaxKind)>,
paren_level: usize,
rule_state: RuleState,
/// Whether we are inside the outer `{` `}` macro block that holds the rules
in_invoc_body: bool,
}
impl MacroMatcherParseState {
fn new() -> Self {
MacroMatcherParseState {
paren_ty: None,
paren_level: 0,
in_invoc_body: false,
rule_state: RuleState::None,
}
}
}
#[derive(Copy, Clone, Debug, PartialEq)]
enum RuleState {
Matcher,
Expander,
Between,
None,
}
impl RuleState {
fn transition(&mut self) {
*self = match self {
RuleState::Matcher => RuleState::Between,
RuleState::Expander => RuleState::None,
RuleState::Between => RuleState::Expander,
RuleState::None => RuleState::Matcher,
};
}
}
fn update_macro_rules_state(state: &mut MacroMatcherParseState, tok: &SyntaxToken) {
if !state.in_invoc_body {
if tok.kind() == T!['{'] {
state.in_invoc_body = true;
}
return;
}
match state.paren_ty {
Some((open, close)) => {
if tok.kind() == open {
state.paren_level += 1;
} else if tok.kind() == close {
state.paren_level -= 1;
if state.paren_level == 0 {
state.rule_state.transition();
state.paren_ty = None;
}
}
}
None => {
match tok.kind() {
T!['('] => {
state.paren_ty = Some((T!['('], T![')']));
}
T!['{'] => {
state.paren_ty = Some((T!['{'], T!['}']));
}
T!['['] => {
state.paren_ty = Some((T!['['], T![']']));
}
_ => (),
}
if state.paren_ty.is_some() {
state.paren_level = 1;
state.rule_state.transition();
}
}
}
}
fn is_metavariable(element: SyntaxElement) -> Option<TextRange> {
let tok = element.as_token()?;
match tok.kind() {
kind if kind == SyntaxKind::IDENT || kind.is_keyword() => {
if let Some(_dollar) = tok.prev_token().filter(|t| t.kind() == SyntaxKind::DOLLAR) {
return Some(tok.text_range());
}
}
_ => (),
};
None
}
|
