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//! Patterns telling us certain facts about current syntax element, they are used in completion context
//!
//! Most logic in this module first expands the token below the cursor to a maximum node that acts similar to the token itself.
//! This means we for example expand a NameRef token to its outermost Path node, as semantically these act in the same location
//! and the completions usually query for path specific things on the Path context instead. This simplifies some location handling.
use syntax::{
ast::{self, HasLoopBody},
match_ast, AstNode, SyntaxElement,
SyntaxKind::*,
SyntaxNode, SyntaxToken,
};
#[cfg(test)]
use crate::tests::check_pattern_is_applicable;
pub(crate) fn previous_token(element: SyntaxElement) -> Option<SyntaxToken> {
element.into_token().and_then(previous_non_trivia_token)
}
pub(crate) fn is_in_token_of_for_loop(element: SyntaxElement) -> bool {
// oh my ...
(|| {
let syntax_token = element.into_token()?;
let range = syntax_token.text_range();
let for_expr = syntax_token.parent_ancestors().find_map(ast::ForExpr::cast)?;
// check if the current token is the `in` token of a for loop
if let Some(token) = for_expr.in_token() {
return Some(syntax_token == token);
}
let pat = for_expr.pat()?;
if range.end() < pat.syntax().text_range().end() {
// if we are inside or before the pattern we can't be at the `in` token position
return None;
}
let next_sibl = next_non_trivia_sibling(pat.syntax().clone().into())?;
Some(match next_sibl {
// the loop body is some node, if our token is at the start we are at the `in` position,
// otherwise we could be in a recovered expression, we don't wanna ruin completions there
syntax::NodeOrToken::Node(n) => n.text_range().start() == range.start(),
// the loop body consists of a single token, if we are this we are certainly at the `in` token position
syntax::NodeOrToken::Token(t) => t == syntax_token,
})
})()
.unwrap_or(false)
}
#[test]
fn test_for_is_prev2() {
check_pattern_is_applicable(r"fn __() { for i i$0 }", is_in_token_of_for_loop);
}
pub(crate) fn is_in_loop_body(node: &SyntaxNode) -> bool {
node.ancestors()
.take_while(|it| it.kind() != FN && it.kind() != CLOSURE_EXPR)
.find_map(|it| {
let loop_body = match_ast! {
match it {
ast::ForExpr(it) => it.loop_body(),
ast::WhileExpr(it) => it.loop_body(),
ast::LoopExpr(it) => it.loop_body(),
_ => None,
}
};
loop_body.filter(|it| it.syntax().text_range().contains_range(node.text_range()))
})
.is_some()
}
fn previous_non_trivia_token(token: SyntaxToken) -> Option<SyntaxToken> {
let mut token = token.prev_token();
while let Some(inner) = token {
if !inner.kind().is_trivia() {
return Some(inner);
} else {
token = inner.prev_token();
}
}
None
}
fn next_non_trivia_sibling(ele: SyntaxElement) -> Option<SyntaxElement> {
let mut e = ele.next_sibling_or_token();
while let Some(inner) = e {
if !inner.kind().is_trivia() {
return Some(inner);
} else {
e = inner.next_sibling_or_token();
}
}
None
}
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