rename ra_ide_api -> ra_ide

crates/ra_ide/src/expand_macro.rs

@@ -0,0 +1,295 @@
+//! 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, source.with_value(&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: hir::Source<&ast::MacroCall>,
+) -> Option<SyntaxNode> {
+    let analyzer = hir::SourceAnalyzer::new(db, source, None);
+    let expansion = analyzer.expand(db, macro_call)?;
+    let macro_file_id = expansion.file_id();
+    let mut 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 node = hir::Source::new(macro_file_id, &child);
+        if let Some(new_node) = expand_macro_recur(db, source, node) {
+            // 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 {
+                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 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(|it| is_text(it), false) { " " } else { "" };
+                format!("{}{{\n{}", leading_space, "  ".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 => 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 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
+}
+"###);
+    }
+
+    #[test]
+    fn macro_expand_match_ast() {
+        let res = check_expand_macro(
+            r#"
+        //- /lib.rs
+        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::ImplBlock(it) => {},
+                    _ => { continue },
+                }
+            }
+        }
+        "#,
+        );
+
+        assert_eq!(res.name, "match_ast");
+        assert_snapshot!(res.expansion, @r###"
+{
+  if let Some(it) = ast::TraitDef::cast(container.clone()){}
+  else if let Some(it) = ast::ImplBlock::cast(container.clone()){}
+  else {
+    {
+      continue
+    }
+  }
+}
+"###);
+    }
+
+    #[test]
+    fn macro_expand_match_ast_inside_let_statement() {
+        let res = check_expand_macro(
+            r#"
+        //- /lib.rs
+        macro_rules! match_ast {
+            (match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };        
+            (match ($node:expr) {}) => {{}};
+        }        
+
+        fn main() {        
+            let p = f(|it| {
+                let res = mat<|>ch_ast! { match c {}};
+                Some(res)
+            })?;
+        }
+        "#,
+        );
+
+        assert_eq!(res.name, "match_ast");
+        assert_snapshot!(res.expansion, @r###"{}"###);
+    }
+
+    #[test]
+    fn macro_expand_inner_macro_fail_to_expand() {
+        let res = check_expand_macro(
+            r#"
+        //- /lib.rs
+        macro_rules! bar {
+            (BAD) => {};
+        }
+        macro_rules! foo {
+            () => {bar!()};
+        }        
+
+        fn main() {        
+            let res = fo<|>o!();
+        }
+        "#,
+        );
+
+        assert_eq!(res.name, "foo");
+        assert_snapshot!(res.expansion, @r###"bar!()"###);
+    }
+
+    #[test]
+    fn macro_expand_with_dollar_crate() {
+        let res = check_expand_macro(
+            r#"
+        //- /lib.rs
+        #[macro_export]
+        macro_rules! bar {
+            () => {0};
+        }
+        macro_rules! foo {
+            () => {$crate::bar!()};
+        }        
+
+        fn main() {        
+            let res = fo<|>o!();
+        }
+        "#,
+        );
+
+        assert_eq!(res.name, "foo");
+        assert_snapshot!(res.expansion, @r###"0"###);
+    }
+}