Rename ra_ide -> ide

crates/ide/src/expand_macro.rs

@@ -0,0 +1,283 @@
+use hir::Semantics;
+use ide_db::RootDatabase;
+use syntax::{
+    algo::{find_node_at_offset, SyntaxRewriter},
+    ast, AstNode, NodeOrToken, SyntaxKind,
+    SyntaxKind::*,
+    SyntaxNode, WalkEvent, T,
+};
+
+use crate::FilePosition;
+
+pub struct ExpandedMacro {
+    pub name: String,
+    pub expansion: String,
+}
+
+// Feature: Expand Macro Recursively
+//
+// Shows the full macro expansion of the macro at current cursor.
+//
+// |===
+// | Editor  | Action Name
+//
+// | VS Code | **Rust Analyzer: Expand macro recursively**
+// |===
+pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<ExpandedMacro> {
+    let sema = Semantics::new(db);
+    let file = sema.parse(position.file_id);
+    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 expanded = expand_macro_recur(&sema, &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(
+    sema: &Semantics<RootDatabase>,
+    macro_call: &ast::MacroCall,
+) -> Option<SyntaxNode> {
+    let mut expanded = sema.expand(macro_call)?;
+
+    let children = expanded.descendants().filter_map(ast::MacroCall::cast);
+    let mut rewriter = SyntaxRewriter::default();
+
+    for child in children.into_iter() {
+        if let Some(new_node) = expand_macro_recur(sema, &child) {
+            // Replace the whole node if it is root
+            // `replace_descendants` will not replace the parent node
+            // but `SyntaxNode::descendants include itself
+            if expanded == *child.syntax() {
+                expanded = new_node;
+            } else {
+                rewriter.replace(child.syntax(), &new_node)
+            }
+        }
+    }
+
+    let res = rewriter.rewrite(&expanded);
+    Some(res)
+}
+
+// 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 {
+    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(f).unwrap_or(default) };
+
+        res += &match token.kind() {
+            k if is_text(k) && is_next(|it| !it.is_punct(), true) => token.text().to_string() + " ",
+            L_CURLY if is_next(|it| it != R_CURLY, true) => {
+                indent += 1;
+                let leading_space = if is_last(is_text, false) { " " } else { "" };
+                format!("{}{{\n{}", leading_space, "  ".repeat(indent))
+            }
+            R_CURLY if is_last(|it| it != L_CURLY, true) => {
+                indent = indent.saturating_sub(1);
+                format!("\n{}}}", "  ".repeat(indent))
+            }
+            R_CURLY => 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());
+    }
+
+    return res;
+
+    fn is_text(k: SyntaxKind) -> bool {
+        k.is_keyword() || k.is_literal() || k == IDENT
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use expect::{expect, Expect};
+
+    use crate::mock_analysis::analysis_and_position;
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        let (analysis, pos) = analysis_and_position(ra_fixture);
+        let expansion = analysis.expand_macro(pos).unwrap().unwrap();
+        let actual = format!("{}\n{}", expansion.name, expansion.expansion);
+        expect.assert_eq(&actual);
+    }
+
+    #[test]
+    fn macro_expand_recursive_expansion() {
+        check(
+            r#"
+macro_rules! bar {
+    () => { fn  b() {} }
+}
+macro_rules! foo {
+    () => { bar!(); }
+}
+macro_rules! baz {
+    () => { foo!(); }
+}
+f<|>oo!();
+"#,
+            expect![[r#"
+                foo
+                fn b(){}
+            "#]],
+        );
+    }
+
+    #[test]
+    fn macro_expand_multiple_lines() {
+        check(
+            r#"
+macro_rules! foo {
+    () => {
+        fn some_thing() -> u32 {
+            let a = 0;
+            a + 10
+        }
+    }
+}
+f<|>oo!();
+        "#,
+            expect![[r#"
+            foo
+            fn some_thing() -> u32 {
+              let a = 0;
+              a+10
+            }"#]],
+        );
+    }
+
+    #[test]
+    fn macro_expand_match_ast() {
+        check(
+            r#"
+macro_rules! match_ast {
+    (match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };
+    (match ($node:expr) {
+        $( ast::$ast:ident($it:ident) => $res:block, )*
+        _ => $catch_all:expr $(,)?
+    }) => {{
+        $( if let Some($it) = ast::$ast::cast($node.clone()) $res else )*
+        { $catch_all }
+    }};
+}
+
+fn main() {
+    mat<|>ch_ast! {
+        match container {
+            ast::TraitDef(it) => {},
+            ast::ImplDef(it) => {},
+            _ => { continue },
+        }
+    }
+}
+"#,
+            expect![[r#"
+       match_ast
+       {
+         if let Some(it) = ast::TraitDef::cast(container.clone()){}
+         else if let Some(it) = ast::ImplDef::cast(container.clone()){}
+         else {
+           {
+             continue
+           }
+         }
+       }"#]],
+        );
+    }
+
+    #[test]
+    fn macro_expand_match_ast_inside_let_statement() {
+        check(
+            r#"
+macro_rules! match_ast {
+    (match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };
+    (match ($node:expr) {}) => {{}};
+}
+
+fn main() {
+    let p = f(|it| {
+        let res = mat<|>ch_ast! { match c {}};
+        Some(res)
+    })?;
+}
+"#,
+            expect![[r#"
+                match_ast
+                {}
+            "#]],
+        );
+    }
+
+    #[test]
+    fn macro_expand_inner_macro_fail_to_expand() {
+        check(
+            r#"
+macro_rules! bar {
+    (BAD) => {};
+}
+macro_rules! foo {
+    () => {bar!()};
+}
+
+fn main() {
+    let res = fo<|>o!();
+}
+"#,
+            expect![[r#"
+                foo
+            "#]],
+        );
+    }
+
+    #[test]
+    fn macro_expand_with_dollar_crate() {
+        check(
+            r#"
+#[macro_export]
+macro_rules! bar {
+    () => {0};
+}
+macro_rules! foo {
+    () => {$crate::bar!()};
+}
+
+fn main() {
+    let res = fo<|>o!();
+}
+"#,
+            expect![[r#"
+                foo
+                0 "#]],
+        );
+    }
+}