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use std::sync::Arc;
use ra_db::{SyntaxDatabase, LocalSyntaxPtr};
use ra_syntax::{
TextRange, TextUnit, SourceFileNode, AstNode, SyntaxNode,
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
pub text: String,
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct MacroExpansion {
text: String,
ranges_map: Vec<(TextRange, TextRange)>,
ptr: LocalSyntaxPtr,
}
salsa::query_group! {
pub trait MacroDatabase: SyntaxDatabase {
fn expand_macro(def: MacroDef, input: MacroInput) -> Option<Arc<MacroExpansion>> {
type ExpandMacroQuery;
}
}
}
fn expand_macro(
_db: &impl MacroDatabase,
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 ptr = LocalSyntaxPtr::new(match_arg.syntax());
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,
ptr,
};
Some(Arc::new(res))
}
impl MacroExpansion {
pub fn file(&self) -> SourceFileNode {
SourceFileNode::parse(&self.text)
}
pub fn syntax(&self) -> SyntaxNode {
self.ptr.resolve(&self.file())
}
pub fn map_range_back(&self, tgt_range: TextRange) -> Option<TextRange> {
for (s_range, t_range) in self.ranges_map.iter() {
if tgt_range.is_subrange(&t_range) {
let tgt_at_zero_range = tgt_range - tgt_range.start();
let tgt_range_offset = tgt_range.start() - t_range.start();
let src_range = tgt_at_zero_range + tgt_range_offset + s_range.start();
return Some(src_range);
}
}
None
}
pub fn map_range_forward(&self, src_range: TextRange) -> Option<TextRange> {
for (s_range, t_range) in self.ranges_map.iter() {
if src_range.is_subrange(&s_range) {
let src_at_zero_range = src_range - src_range.start();
let src_range_offset = src_range.start() - s_range.start();
let src_range = src_at_zero_range + src_range_offset + t_range.start();
return Some(src_range);
}
}
None
}
}
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