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use std::sync::Arc;
use ra_db::SyntaxDatabase;
use ra_syntax::{TextRange, TextUnit, SourceFileNode, AstNode, ast};
// Hard-coded defs for now :-(
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum MacroDef {
CTry,
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct MacroInput {
// Should be token trees
text: String,
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct MacroExpansion {
text: String,
ranges_map: Vec<(TextRange, TextRange)>,
}
salsa::query_group! {
pub trait MacrosDatabase: SyntaxDatabase {
fn expand_macro(def: MacroDef, input: MacroInput) -> Option<Arc<MacroExpansion>> {
type ExpandMacroQuery;
}
}
}
fn expand_macro(
_db: &impl MacrosDatabase,
def: MacroDef,
input: MacroInput,
) -> Option<Arc<MacroExpansion>> {
let MacroDef::CTry = def;
let text = format!(
r"
fn dummy() {{
match {} {{
None => return Ok(None),
Some(it) => it,
}}
}}",
input.text
);
let file = SourceFileNode::parse(&text);
let match_expr = file.syntax().descendants().find_map(ast::MatchExpr::cast)?;
let match_arg = match_expr.expr()?;
let src_range = TextRange::offset_len(0.into(), TextUnit::of_str(&input.text));
let ranges_map = vec![(src_range, match_arg.syntax().range())];
let res = MacroExpansion { text, ranges_map };
Some(Arc::new(res))
}
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