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/// Begining of macro expansion.
///
/// This code should be moved out of ra_analysis into hir (?) ideally.
use ra_syntax::{ast, AstNode, SourceFileNode, TextRange};
use crate::{db::RootDatabase, FileId};
pub(crate) fn expand(
_db: &RootDatabase,
_file_id: FileId,
macro_call: ast::MacroCall,
) -> Option<MacroExpansion> {
let path = macro_call.path()?;
if path.qualifier().is_some() {
return None;
}
let name_ref = path.segment()?.name_ref()?;
if name_ref.text() != "ctry" {
return None;
}
let arg = macro_call.token_tree()?;
let text = format!(
r"
fn dummy() {{
match {} {{
None => return Ok(None),
Some(it) => it,
}}
}}",
arg.syntax().text()
);
let file = SourceFileNode::parse(&text);
let match_expr = file.syntax().descendants().find_map(ast::MatchExpr::cast)?;
let match_arg = match_expr.expr()?;
let ranges_map = vec![(arg.syntax().range(), match_arg.syntax().range())];
let res = MacroExpansion {
source_file: file,
ranges_map,
};
Some(res)
}
pub(crate) struct MacroExpansion {
pub(crate) source_file: SourceFileNode,
pub(crate) ranges_map: Vec<(TextRange, TextRange)>,
}
impl MacroExpansion {
pub(crate) fn source_file(&self) -> &SourceFileNode {
&self.source_file
}
pub(crate) 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
}
}
|
