1 files changed, 207 insertions, 25 deletions

diff --git a/crates/ra_hir_expand/src/builtin_macro.rs b/crates/ra_hir_expand/src/builtin_macro.rs
index 97fb0cb55..c0e0436c0 100644
--- a/crates/ra_hir_expand/src/builtin_macro.rs
+++ b/crates/ra_hir_expand/src/builtin_macro.rs
@@ -8,35 +8,47 @@ use crate::{
 
 use crate::quote;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub enum BuiltinExpander {
-    Line,
-}
+macro_rules! register_builtin {
+    ( $(($name:ident, $kind: ident) => $expand:ident),* ) => {
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+        pub enum BuiltinFnLikeExpander {
+            $($kind),*
+        }
 
-impl BuiltinExpander {
-    pub fn expand(
-        &self,
-        db: &dyn AstDatabase,
-        id: MacroCallId,
-        tt: &tt::Subtree,
-    ) -> Result<tt::Subtree, mbe::ExpandError> {
-        match self {
-            BuiltinExpander::Line => line_expand(db, id, tt),
+        impl BuiltinFnLikeExpander {
+            pub fn expand(
+                &self,
+                db: &dyn AstDatabase,
+                id: MacroCallId,
+                tt: &tt::Subtree,
+            ) -> Result<tt::Subtree, mbe::ExpandError> {
+                let expander = match *self {
+                    $( BuiltinFnLikeExpander::$kind => $expand, )*
+                };
+                expander(db, id, tt)
+            }
         }
-    }
+
+        pub fn find_builtin_macro(
+            ident: &name::Name,
+            krate: CrateId,
+            ast_id: AstId<ast::MacroCall>,
+        ) -> Option<MacroDefId> {
+            let kind = match ident {
+                 $( id if id == &name::$name => BuiltinFnLikeExpander::$kind, )*
+                 _ => return None,
+            };
+
+            Some(MacroDefId { krate, ast_id, kind: MacroDefKind::BuiltIn(kind) })
+        }
+    };
 }
 
-pub fn find_builtin_macro(
-    ident: &name::Name,
-    krate: CrateId,
-    ast_id: AstId<ast::MacroCall>,
-) -> Option<MacroDefId> {
-    // FIXME: Better registering method
-    if ident == &name::LINE_MACRO {
-        Some(MacroDefId { krate, ast_id, kind: MacroDefKind::BuiltIn(BuiltinExpander::Line) })
-    } else {
-        None
-    }
+register_builtin! {
+    (COLUMN_MACRO, Column) => column_expand,
+    (FILE_MACRO, File) => file_expand,
+    (LINE_MACRO, Line) => line_expand,
+    (STRINGIFY_MACRO, Stringify) => stringify_expand
 }
 
 fn to_line_number(db: &dyn AstDatabase, file: HirFileId, pos: TextUnit) -> usize {
@@ -78,3 +90,173 @@ fn line_expand(
 
     Ok(expanded)
 }
+
+fn stringify_expand(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+    _tt: &tt::Subtree,
+) -> Result<tt::Subtree, mbe::ExpandError> {
+    let loc = db.lookup_intern_macro(id);
+    let macro_call = loc.ast_id.to_node(db);
+
+    let macro_content = {
+        let arg = macro_call.token_tree().ok_or_else(|| mbe::ExpandError::UnexpectedToken)?;
+        let macro_args = arg.syntax().clone();
+        let text = macro_args.text();
+        let without_parens = TextUnit::of_char('(')..text.len() - TextUnit::of_char(')');
+        text.slice(without_parens).to_string()
+    };
+
+    let expanded = quote! {
+        #macro_content
+    };
+
+    Ok(expanded)
+}
+
+fn to_col_number(db: &dyn AstDatabase, file: HirFileId, pos: TextUnit) -> usize {
+    // FIXME: Use expansion info
+    let file_id = file.original_file(db);
+    let text = db.file_text(file_id);
+    let mut col_num = 1;
+
+    for c in text[..pos.to_usize()].chars().rev() {
+        if c == '\n' {
+            break;
+        }
+        col_num = col_num + 1;
+    }
+
+    col_num
+}
+
+fn column_expand(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+    _tt: &tt::Subtree,
+) -> Result<tt::Subtree, mbe::ExpandError> {
+    let loc = db.lookup_intern_macro(id);
+    let macro_call = loc.ast_id.to_node(db);
+
+    let _arg = macro_call.token_tree().ok_or_else(|| mbe::ExpandError::UnexpectedToken)?;
+    let col_start = macro_call.syntax().text_range().start();
+
+    let file = id.as_file(MacroFileKind::Expr);
+    let col_num = to_col_number(db, file, col_start);
+
+    let expanded = quote! {
+        #col_num
+    };
+
+    Ok(expanded)
+}
+
+fn file_expand(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+    _tt: &tt::Subtree,
+) -> Result<tt::Subtree, mbe::ExpandError> {
+    let loc = db.lookup_intern_macro(id);
+    let macro_call = loc.ast_id.to_node(db);
+
+    let _ = macro_call.token_tree().ok_or_else(|| mbe::ExpandError::UnexpectedToken)?;
+
+    // FIXME: RA purposefully lacks knowledge of absolute file names
+    // so just return "".
+    let file_name = "";
+
+    let expanded = quote! {
+        #file_name
+    };
+
+    Ok(expanded)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{test_db::TestDB, MacroCallLoc};
+    use ra_db::{fixture::WithFixture, SourceDatabase};
+
+    fn expand_builtin_macro(s: &str, expander: BuiltinFnLikeExpander) -> String {
+        let (db, file_id) = TestDB::with_single_file(&s);
+        let parsed = db.parse(file_id);
+        let macro_calls: Vec<_> =
+            parsed.syntax_node().descendants().filter_map(|it| ast::MacroCall::cast(it)).collect();
+
+        let ast_id_map = db.ast_id_map(file_id.into());
+
+        // the first one should be a macro_rules
+        let def = MacroDefId {
+            krate: CrateId(0),
+            ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_calls[0])),
+            kind: MacroDefKind::BuiltIn(expander),
+        };
+
+        let loc = MacroCallLoc {
+            def,
+            ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_calls[1])),
+        };
+
+        let id = db.intern_macro(loc);
+        let parsed = db.parse_or_expand(id.as_file(MacroFileKind::Expr)).unwrap();
+
+        parsed.text().to_string()
+    }
+
+    #[test]
+    fn test_column_expand() {
+        let expanded = expand_builtin_macro(
+            r#"
+        #[rustc_builtin_macro]
+        macro_rules! column {() => {}}
+        column!()
+"#,
+            BuiltinFnLikeExpander::Column,
+        );
+
+        assert_eq!(expanded, "9");
+    }
+
+    #[test]
+    fn test_line_expand() {
+        let expanded = expand_builtin_macro(
+            r#"
+        #[rustc_builtin_macro]
+        macro_rules! line {() => {}}
+        line!()
+"#,
+            BuiltinFnLikeExpander::Line,
+        );
+
+        assert_eq!(expanded, "4");
+    }
+
+    #[test]
+    fn test_stringify_expand() {
+        let expanded = expand_builtin_macro(
+            r#"
+        #[rustc_builtin_macro]
+        macro_rules! stringify {() => {}}
+        stringify!(a b c)
+"#,
+            BuiltinFnLikeExpander::Stringify,
+        );
+
+        assert_eq!(expanded, "\"a b c\"");
+    }
+
+    #[test]
+    fn test_file_expand() {
+        let expanded = expand_builtin_macro(
+            r#"
+        #[rustc_builtin_macro]
+        macro_rules! file {() => {}}
+        file!()
+"#,
+            BuiltinFnLikeExpander::File,
+        );
+
+        assert_eq!(expanded, "\"\"");
+    }
+}