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use libsyntax2::{
File, TextUnit, AstNode,
ast::self,
algo::{
ancestors,
},
};
use {
AtomEdit, find_node_at_offset,
scope::{FnScopes, compute_scopes},
};
#[derive(Debug)]
pub struct CompletionItem {
pub name: String,
}
pub fn scope_completion(file: &File, offset: TextUnit) -> Option<Vec<CompletionItem>> {
// Insert a fake ident to get a valid parse tree
let file = {
let edit = AtomEdit::insert(offset, "intellijRulezz".to_string());
// Don't bother with completion if incremental reparse fails
file.incremental_reparse(&edit)?
};
let name_ref = find_node_at_offset::<ast::NameRef>(file.syntax(), offset)?;
let fn_def = ancestors(name_ref.syntax()).filter_map(ast::FnDef::cast).next()?;
let scopes = compute_scopes(fn_def);
Some(complete(name_ref, &scopes))
}
fn complete(name_ref: ast::NameRef, scopes: &FnScopes) -> Vec<CompletionItem> {
scopes.scope_chain(name_ref.syntax())
.flat_map(|scope| scopes.entries(scope).iter())
.map(|entry| CompletionItem {
name: entry.name().to_string()
})
.collect()
}
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