diff options
| -rw-r--r-- | src/librustc/front/config.rs | 5 | ||||
| -rw-r--r-- | src/librustc/plugin/load.rs | 5 | ||||
| -rw-r--r-- | src/libsyntax/ast_map.rs | 9 | ||||
| -rw-r--r-- | src/libsyntax/ext/expand.rs | 7 | ||||
| -rw-r--r-- | src/libsyntax/fold.rs | 46 | ||||
| -rw-r--r-- | src/libsyntax/visit.rs | 13 |
6 files changed, 71 insertions, 14 deletions
diff --git a/src/librustc/front/config.rs b/src/librustc/front/config.rs index 9bff6620aaa..0c39cf350a6 100644 --- a/src/librustc/front/config.rs +++ b/src/librustc/front/config.rs @@ -14,6 +14,8 @@ use syntax::codemap; use std::gc::{Gc, GC}; +/// A folder that strips out items that do not belong in the current +/// configuration. struct Context<'a> { in_cfg: |attrs: &[ast::Attribute]|: 'a -> bool, } @@ -41,6 +43,9 @@ impl<'a> fold::Folder for Context<'a> { fn fold_expr(&mut self, expr: Gc<ast::Expr>) -> Gc<ast::Expr> { fold_expr(self, expr) } + fn fold_mac(&mut self, mac: &ast::Mac) -> ast::Mac { + fold::fold_mac(mac, self) + } } pub fn strip_items(krate: ast::Crate, diff --git a/src/librustc/plugin/load.rs b/src/librustc/plugin/load.rs index 79d0690653f..499cffa42aa 100644 --- a/src/librustc/plugin/load.rs +++ b/src/librustc/plugin/load.rs @@ -72,6 +72,7 @@ pub fn load_plugins(sess: &Session, krate: &ast::Crate) -> Plugins { loader.plugins } +// note that macros aren't expanded yet, and therefore macros can't add plugins. impl<'a> Visitor<()> for PluginLoader<'a> { fn visit_view_item(&mut self, vi: &ast::ViewItem, _: ()) { match vi.node { @@ -109,6 +110,10 @@ impl<'a> Visitor<()> for PluginLoader<'a> { _ => (), } } + fn visit_mac(&mut self, _: &ast::Mac, _:()) { + // bummer... can't see plugins inside macros. + // do nothing. + } } impl<'a> PluginLoader<'a> { diff --git a/src/libsyntax/ast_map.rs b/src/libsyntax/ast_map.rs index 25c8e81bdbc..de2ecd9a264 100644 --- a/src/libsyntax/ast_map.rs +++ b/src/libsyntax/ast_map.rs @@ -112,6 +112,7 @@ pub enum Node { NodeLifetime(Gc<Lifetime>), } +/// Represents an entry and its parent Node ID /// The odd layout is to bring down the total size. #[deriving(Clone)] enum MapEntry { @@ -184,6 +185,8 @@ impl MapEntry { } } +/// Represents a mapping from Node IDs to AST elements and their parent +/// Node IDs pub struct Map { /// NodeIds are sequential integers from 0, so we can be /// super-compact by storing them in a vector. Not everything with @@ -430,6 +433,8 @@ pub trait FoldOps { } } +/// A Folder that walks over an AST and constructs a Node ID Map. Its +/// fold_ops argument has the opportunity to replace Node IDs and spans. pub struct Ctx<'a, F> { map: &'a Map, /// The node in which we are currently mapping (an item or a method). @@ -584,6 +589,10 @@ impl<'a, F: FoldOps> Folder for Ctx<'a, F> { self.insert(lifetime.id, EntryLifetime(self.parent, box(GC) lifetime)); lifetime } + + fn fold_mac(&mut self, mac: &Mac) -> Mac { + fold::fold_mac(mac, self) + } } pub fn map_crate<F: FoldOps>(krate: Crate, fold_ops: F) -> (Crate, Map) { diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs index e8a78e85d89..084faca02c5 100644 --- a/src/libsyntax/ext/expand.rs +++ b/src/libsyntax/ext/expand.rs @@ -753,7 +753,6 @@ impl Visitor<()> for PatIdentFinder { _ => visit::walk_pat(self, pattern, ()) } } - } /// find the PatIdent paths in a pattern @@ -902,6 +901,9 @@ impl<'a> Folder for IdentRenamer<'a> { ctxt: mtwt::apply_renames(self.renames, id.ctxt), } } + fn fold_mac(&mut self, macro: &ast::Mac) -> ast::Mac { + fold::fold_mac(macro, self) + } } /// A tree-folder that applies every rename in its list to @@ -931,6 +933,9 @@ impl<'a> Folder for PatIdentRenamer<'a> { _ => noop_fold_pat(pat, self) } } + fn fold_mac(&mut self, macro: &ast::Mac) -> ast::Mac { + fold::fold_mac(macro, self) + } } // expand a method diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs index f7cb1ae1934..3e3b57be6e4 100644 --- a/src/libsyntax/fold.rs +++ b/src/libsyntax/fold.rs @@ -8,6 +8,16 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. +//! A Folder represents an AST->AST fold; it accepts an AST piece, +//! and returns a piece of the same type. So, for instance, macro +//! expansion is a Folder that walks over an AST and produces another +//! AST. +//! +//! Note: using a Folder (other than the MacroExpander Folder) on +//! an AST before macro expansion is probably a bad idea. For instance, +//! a folder renaming item names in a module will miss all of those +//! that are created by the expansion of a macro. + use ast::*; use ast; use ast_util; @@ -299,17 +309,13 @@ pub trait Folder { } } - fn fold_mac(&mut self, macro: &Mac) -> Mac { - Spanned { - node: match macro.node { - MacInvocTT(ref p, ref tts, ctxt) => { - MacInvocTT(self.fold_path(p), - fold_tts(tts.as_slice(), self), - ctxt) - } - }, - span: self.new_span(macro.span) - } + fn fold_mac(&mut self, _macro: &Mac) -> Mac { + fail!("fold_mac disabled by default"); + // NB: see note about macros above. + // if you really want a folder that + // works on macros, use this + // definition in your trait impl: + // fold::fold_mac(_macro, self) } fn map_exprs(&self, f: |Gc<Expr>| -> Gc<Expr>, @@ -361,6 +367,20 @@ pub trait Folder { } + +pub fn fold_mac<T: Folder>(macro: &Mac, fld: &mut T) -> Mac { + Spanned { + node: match macro.node { + MacInvocTT(ref p, ref tts, ctxt) => { + MacInvocTT(fld.fold_path(p), + fold_tts(tts.as_slice(), fld), + ctxt) + } + }, + span: fld.new_span(macro.span) + } +} + /* some little folds that probably aren't useful to have in Folder itself*/ //used in noop_fold_item and noop_fold_crate and noop_fold_crate_directive @@ -986,6 +1006,7 @@ mod test { use util::parser_testing::{string_to_crate, matches_codepattern}; use parse::token; use print::pprust; + use fold; use super::*; // this version doesn't care about getting comments or docstrings in. @@ -1001,6 +1022,9 @@ mod test { fn fold_ident(&mut self, _: ast::Ident) -> ast::Ident { token::str_to_ident("zz") } + fn fold_mac(&mut self, macro: &ast::Mac) -> ast::Mac { + fold::fold_mac(macro, self) + } } // maybe add to expand.rs... diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs index 9298b58c426..7caaf2f6cc1 100644 --- a/src/libsyntax/visit.rs +++ b/src/libsyntax/visit.rs @@ -20,6 +20,10 @@ //! execute before AST node B, then A is visited first. The borrow checker in //! particular relies on this property. //! +//! Note: walking an AST before macro expansion is probably a bad idea. For +//! instance, a walker looking for item names in a module will miss all of +//! those that are created by the expansion of a macro. + use abi::Abi; use ast::*; use ast; @@ -124,8 +128,13 @@ pub trait Visitor<E: Clone> { fn visit_explicit_self(&mut self, es: &ExplicitSelf, e: E) { walk_explicit_self(self, es, e) } - fn visit_mac(&mut self, macro: &Mac, e: E) { - walk_mac(self, macro, e) + fn visit_mac(&mut self, _macro: &Mac, _e: E) { + fail!("visit_mac disabled by default"); + // NB: see note about macros above. + // if you really want a visitor that + // works on macros, use this + // definition in your trait impl: + // visit::walk_mac(self, _macro, _e) } fn visit_path(&mut self, path: &Path, _id: ast::NodeId, e: E) { walk_path(self, path, e) |