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|
//! This modules implements "expand macro" functionality in the IDE
use crate::{db::RootDatabase, FilePosition};
use hir::db::AstDatabase;
use ra_db::SourceDatabase;
use rustc_hash::FxHashMap;
use ra_syntax::{
algo::{find_node_at_offset, replace_descendants},
ast::{self},
AstNode, NodeOrToken, SyntaxKind, SyntaxNode, WalkEvent, T,
};
pub struct ExpandedMacro {
pub name: String,
pub expansion: String,
}
pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<ExpandedMacro> {
let parse = db.parse(position.file_id);
let file = parse.tree();
let name_ref = find_node_at_offset::<ast::NameRef>(file.syntax(), position.offset)?;
let mac = name_ref.syntax().ancestors().find_map(ast::MacroCall::cast)?;
let source = hir::Source::new(position.file_id.into(), mac.syntax());
let expanded = expand_macro_recur(db, source, &mac)?;
// FIXME:
// macro expansion may lose all white space information
// But we hope someday we can use ra_fmt for that
let expansion = insert_whitespaces(expanded);
Some(ExpandedMacro { name: name_ref.text().to_string(), expansion })
}
fn expand_macro_recur(
db: &RootDatabase,
source: hir::Source<&SyntaxNode>,
macro_call: &ast::MacroCall,
) -> Option<SyntaxNode> {
let analyzer = hir::SourceAnalyzer::new(db, source, None);
let expansion = analyzer.expand(db, ¯o_call)?;
let macro_file_id = expansion.file_id();
let expanded: SyntaxNode = db.parse_or_expand(macro_file_id)?;
let children = expanded.descendants().filter_map(ast::MacroCall::cast);
let mut replaces = FxHashMap::default();
for child in children.into_iter() {
let source = hir::Source::new(macro_file_id, source.value);
let new_node = expand_macro_recur(db, source, &child)?;
replaces.insert(child.syntax().clone().into(), new_node.into());
}
Some(replace_descendants(&expanded, &replaces))
}
// FIXME: It would also be cool to share logic here and in the mbe tests,
// which are pretty unreadable at the moment.
fn insert_whitespaces(syn: SyntaxNode) -> String {
use SyntaxKind::*;
let mut res = String::new();
let mut token_iter = syn
.preorder_with_tokens()
.filter_map(|event| {
if let WalkEvent::Enter(NodeOrToken::Token(token)) = event {
Some(token)
} else {
None
}
})
.peekable();
let mut indent = 0;
let mut last: Option<SyntaxKind> = None;
while let Some(token) = token_iter.next() {
let mut is_next = |f: fn(SyntaxKind) -> bool, default| -> bool {
token_iter.peek().map(|it| f(it.kind())).unwrap_or(default)
};
let is_last = |f: fn(SyntaxKind) -> bool, default| -> bool {
last.map(|it| f(it)).unwrap_or(default)
};
res += &match token.kind() {
k @ _
if (k.is_keyword() || k.is_literal() || k == IDENT)
&& is_next(|it| !it.is_punct(), true) =>
{
token.text().to_string() + " "
}
L_CURLY if is_next(|it| it != R_CURLY, true) => {
indent += 1;
format!(" {{\n{}", " ".repeat(indent))
}
R_CURLY if is_last(|it| it != L_CURLY, true) => {
indent = indent.checked_sub(1).unwrap_or(0);
format!("\n}}{}", " ".repeat(indent))
}
R_CURLY => {
indent = indent.checked_sub(1).unwrap_or(0);
format!("}}\n{}", " ".repeat(indent))
}
T![;] => format!(";\n{}", " ".repeat(indent)),
T![->] => " -> ".to_string(),
T![=] => " = ".to_string(),
T![=>] => " => ".to_string(),
_ => token.text().to_string(),
};
last = Some(token.kind());
}
res
}
#[cfg(test)]
mod tests {
use super::*;
use crate::mock_analysis::analysis_and_position;
use insta::assert_snapshot;
fn check_expand_macro(fixture: &str) -> ExpandedMacro {
let (analysis, pos) = analysis_and_position(fixture);
analysis.expand_macro(pos).unwrap().unwrap()
}
#[test]
fn macro_expand_recursive_expansion() {
let res = check_expand_macro(
r#"
//- /lib.rs
macro_rules! bar {
() => { fn b() {} }
}
macro_rules! foo {
() => { bar!(); }
}
macro_rules! baz {
() => { foo!(); }
}
f<|>oo!();
"#,
);
assert_eq!(res.name, "foo");
assert_snapshot!(res.expansion, @r###"
fn b(){}
"###);
}
#[test]
fn macro_expand_multiple_lines() {
let res = check_expand_macro(
r#"
//- /lib.rs
macro_rules! foo {
() => {
fn some_thing() -> u32 {
let a = 0;
a + 10
}
}
}
f<|>oo!();
"#,
);
assert_eq!(res.name, "foo");
assert_snapshot!(res.expansion, @r###"
fn some_thing() -> u32 {
let a = 0;
a+10
}
"###);
}
}
|
