08b6057538
Macro scope is now delimited by function, block, and module boundaries, except for modules that are marked with #[macro_escape], which allows macros to escape.
589 lines
20 KiB
Rust
589 lines
20 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use core::prelude::*;
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use ast::{crate, expr_, expr_mac, mac_invoc_tt};
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use ast::{tt_delim, tt_tok, item_mac, stmt_, stmt_mac, stmt_expr, stmt_semi};
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use ast;
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use attr;
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use codemap::{span, CallInfo, ExpandedFrom, NameAndSpan};
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use ext::base::*;
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use fold::*;
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use parse::{parser, parse_item_from_source_str, new_parser_from_tts};
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use core::option;
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use core::vec;
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use core::hashmap::LinearMap;
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pub fn expand_expr(extsbox: @mut SyntaxEnv, cx: ext_ctxt,
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e: expr_, s: span, fld: ast_fold,
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orig: fn@(expr_, span, ast_fold) -> (expr_, span))
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-> (expr_, span) {
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return match e {
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// expr_mac should really be expr_ext or something; it's the
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// entry-point for all syntax extensions.
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expr_mac(ref mac) => {
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match (*mac).node {
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// Token-tree macros, these will be the only case when we're
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// finished transitioning.
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mac_invoc_tt(pth, ref tts) => {
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assert (vec::len(pth.idents) == 1u);
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/* using idents and token::special_idents would make the
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the macro names be hygienic */
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let extname = cx.parse_sess().interner.get(pth.idents[0]);
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// leaving explicit deref here to highlight unbox op:
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match (*extsbox).find(&extname) {
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None => {
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cx.span_fatal(pth.span,
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fmt!("macro undefined: '%s'", *extname))
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}
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Some(@SE(NormalTT(SyntaxExpanderTT{expander: exp,
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span: exp_sp}))) => {
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cx.bt_push(ExpandedFrom(CallInfo{
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call_site: s,
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callee: NameAndSpan {
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name: *extname, span: exp_sp
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}
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}));
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let expanded = match exp(cx, (*mac).span, (*tts)) {
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MRExpr(e) => e,
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MRAny(expr_maker,_,_) => expr_maker(),
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_ => cx.span_fatal(
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pth.span, fmt!("non-expr macro in expr pos: %s",
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*extname))
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};
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//keep going, outside-in
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let fully_expanded = fld.fold_expr(expanded).node;
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cx.bt_pop();
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(fully_expanded, s)
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}
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_ => {
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cx.span_fatal(pth.span,
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fmt!("'%s' is not a tt-style macro",
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*extname))
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}
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}
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}
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}
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}
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_ => orig(e, s, fld)
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};
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}
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// This is a secondary mechanism for invoking syntax extensions on items:
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// "decorator" attributes, such as #[auto_encode]. These are invoked by an
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// attribute prefixing an item, and are interpreted by feeding the item
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// through the named attribute _as a syntax extension_ and splicing in the
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// resulting item vec into place in favour of the decorator. Note that
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// these do _not_ work for macro extensions, just ItemDecorator ones.
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//
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// NB: there is some redundancy between this and expand_item, below, and
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// they might benefit from some amount of semantic and language-UI merger.
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pub fn expand_mod_items(extsbox: @mut SyntaxEnv, cx: ext_ctxt,
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module_: ast::_mod, fld: ast_fold,
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orig: fn@(ast::_mod, ast_fold) -> ast::_mod)
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-> ast::_mod {
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// Fold the contents first:
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let module_ = orig(module_, fld);
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// For each item, look through the attributes. If any of them are
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// decorated with "item decorators", then use that function to transform
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// the item into a new set of items.
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let new_items = do vec::flat_map(module_.items) |item| {
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do vec::foldr(item.attrs, ~[*item]) |attr, items| {
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let mname = attr::get_attr_name(attr);
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match (*extsbox).find(&mname) {
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Some(@SE(ItemDecorator(dec_fn))) => {
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cx.bt_push(ExpandedFrom(CallInfo {
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call_site: attr.span,
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callee: NameAndSpan {
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name: /*bad*/ copy *mname,
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span: None
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}
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}));
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let r = dec_fn(cx, attr.span, attr.node.value, items);
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cx.bt_pop();
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r
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},
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_ => items,
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}
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}
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};
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ast::_mod { items: new_items, ..module_ }
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}
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// eval $e with a new exts frame:
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macro_rules! with_exts_frame (
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($extsboxexpr:expr,$e:expr) =>
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({let extsbox = $extsboxexpr;
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let oldexts = *extsbox;
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*extsbox = oldexts.push_frame();
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let result = $e;
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*extsbox = oldexts;
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result
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})
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)
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// When we enter a module, record it, for the sake of `module!`
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pub fn expand_item(extsbox: @mut SyntaxEnv,
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cx: ext_ctxt, &&it: @ast::item, fld: ast_fold,
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orig: fn@(&&v: @ast::item, ast_fold) -> Option<@ast::item>)
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-> Option<@ast::item> {
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// need to do expansion first... it might turn out to be a module.
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let maybe_it = match it.node {
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ast::item_mac(*) => expand_item_mac(extsbox, cx, it, fld),
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_ => Some(it)
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};
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match maybe_it {
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Some(it) => {
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match it.node {
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ast::item_mod(_) | ast::item_foreign_mod(_) => {
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cx.mod_push(it.ident);
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let result =
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// don't push a macro scope for macro_escape:
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if contains_macro_escape(it.attrs) {
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orig(it,fld)
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} else {
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// otherwise, push a scope:
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with_exts_frame!(extsbox,orig(it,fld))
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};
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cx.mod_pop();
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result
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}
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_ => orig(it,fld)
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}
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}
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None => None
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}
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}
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// does this attribute list contain "macro_escape" ?
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fn contains_macro_escape (attrs: &[ast::attribute]) -> bool{
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let mut accum = false;
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do attrs.each |attr| {
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let mname = attr::get_attr_name(attr);
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if (mname == @~"macro_escape") {
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accum = true;
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false
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} else {
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true
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}
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}
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accum
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}
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// this macro disables (one layer of) macro
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// scoping, to allow a block to add macro bindings
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// to its parent env
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macro_rules! without_macro_scoping(
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($extsexpr:expr,$exp:expr) =>
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({
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// only evaluaate this once:
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let exts = $extsexpr;
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// capture the existing binding:
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let existingBlockBinding =
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match exts.find(&@~" block"){
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Some(binding) => binding,
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None => cx.bug("expected to find \" block\" binding")
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};
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// this prevents the block from limiting the macros' scope:
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exts.insert(@~" block",@ScopeMacros(false));
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let result = $exp;
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// reset the block binding. Note that since the original
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// one may have been inherited, this procedure may wind
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// up introducing a block binding where one didn't exist
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// before.
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exts.insert(@~" block",existingBlockBinding);
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result
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}))
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// Support for item-position macro invocations, exactly the same
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// logic as for expression-position macro invocations.
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pub fn expand_item_mac(+extsbox: @mut SyntaxEnv,
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cx: ext_ctxt, &&it: @ast::item,
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fld: ast_fold) -> Option<@ast::item> {
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let (pth, tts) = match it.node {
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item_mac(codemap::spanned { node: mac_invoc_tt(pth, ref tts), _}) => {
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(pth, (*tts))
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}
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_ => cx.span_bug(it.span, ~"invalid item macro invocation")
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};
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let extname = cx.parse_sess().interner.get(pth.idents[0]);
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let expanded = match (*extsbox).find(&extname) {
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None => cx.span_fatal(pth.span,
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fmt!("macro undefined: '%s!'", *extname)),
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Some(@SE(NormalTT(ref expand))) => {
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if it.ident != parse::token::special_idents::invalid {
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cx.span_fatal(pth.span,
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fmt!("macro %s! expects no ident argument, \
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given '%s'", *extname,
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*cx.parse_sess().interner.get(it.ident)));
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}
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cx.bt_push(ExpandedFrom(CallInfo {
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call_site: it.span,
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callee: NameAndSpan {
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name: *extname,
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span: (*expand).span
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}
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}));
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((*expand).expander)(cx, it.span, tts)
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}
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Some(@SE(IdentTT(ref expand))) => {
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if it.ident == parse::token::special_idents::invalid {
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cx.span_fatal(pth.span,
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fmt!("macro %s! expects an ident argument",
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*extname));
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}
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cx.bt_push(ExpandedFrom(CallInfo {
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call_site: it.span,
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callee: NameAndSpan {
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name: *extname,
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span: (*expand).span
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}
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}));
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((*expand).expander)(cx, it.span, it.ident, tts)
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}
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_ => cx.span_fatal(
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it.span, fmt!("%s! is not legal in item position", *extname))
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};
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let maybe_it = match expanded {
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MRItem(it) => fld.fold_item(it),
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MRExpr(_) => cx.span_fatal(pth.span,
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~"expr macro in item position: "
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+ *extname),
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MRAny(_, item_maker, _) =>
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option::chain(item_maker(), |i| {fld.fold_item(i)}),
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MRDef(ref mdef) => {
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extsbox.insert(@/*bad*/ copy mdef.name, @SE((*mdef).ext));
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None
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}
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};
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cx.bt_pop();
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return maybe_it;
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}
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// expand a stmt
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pub fn expand_stmt(extsbox: @mut SyntaxEnv, cx: ext_ctxt,
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&& s: stmt_, sp: span, fld: ast_fold,
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orig: fn@(&&s: stmt_, span, ast_fold) -> (stmt_, span))
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-> (stmt_, span) {
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let (mac, pth, tts, semi) = match s {
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stmt_mac(ref mac, semi) => {
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match (*mac).node {
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mac_invoc_tt(pth, ref tts) => ((*mac), pth, (*tts), semi)
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}
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}
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_ => return orig(s, sp, fld)
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};
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assert(vec::len(pth.idents) == 1u);
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let extname = cx.parse_sess().interner.get(pth.idents[0]);
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let (fully_expanded, sp) = match (*extsbox).find(&extname) {
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None =>
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cx.span_fatal(pth.span, fmt!("macro undefined: '%s'", *extname)),
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Some(@SE(NormalTT(
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SyntaxExpanderTT{expander: exp, span: exp_sp}))) => {
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cx.bt_push(ExpandedFrom(CallInfo {
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call_site: sp,
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callee: NameAndSpan { name: *extname, span: exp_sp }
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}));
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let expanded = match exp(cx, mac.span, tts) {
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MRExpr(e) =>
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@codemap::spanned { node: stmt_expr(e, cx.next_id()),
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span: e.span},
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MRAny(_,_,stmt_mkr) => stmt_mkr(),
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_ => cx.span_fatal(
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pth.span,
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fmt!("non-stmt macro in stmt pos: %s", *extname))
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};
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//keep going, outside-in
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let fully_expanded = fld.fold_stmt(expanded).node;
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cx.bt_pop();
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(fully_expanded, sp)
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}
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_ => {
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cx.span_fatal(pth.span,
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fmt!("'%s' is not a tt-style macro", *extname))
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}
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};
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(match fully_expanded {
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stmt_expr(e, stmt_id) if semi => stmt_semi(e, stmt_id),
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_ => { fully_expanded } /* might already have a semi */
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}, sp)
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}
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pub fn expand_block(extsbox: @mut SyntaxEnv, cx: ext_ctxt,
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&& blk: blk_, sp: span, fld: ast_fold,
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orig: fn@(&&s: blk_, span, ast_fold) -> (blk_, span))
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-> (blk_, span) {
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match (*extsbox).find(&@~" block") {
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// no scope limit on macros in this block, no need
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// to push an exts frame:
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Some(@ScopeMacros(false)) => {
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orig (blk,sp,fld)
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},
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// this block should limit the scope of its macros:
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Some(@ScopeMacros(true)) => {
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// see note below about treatment of exts table
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with_exts_frame!(extsbox,orig(blk,sp,fld))
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},
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_ => cx.span_bug(sp,
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~"expected ScopeMacros binding for \" block\"")
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}
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}
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pub fn new_span(cx: ext_ctxt, sp: span) -> span {
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/* this discards information in the case of macro-defining macros */
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return span {lo: sp.lo, hi: sp.hi, expn_info: cx.backtrace()};
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}
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// FIXME (#2247): this is a moderately bad kludge to inject some macros into
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// the default compilation environment. It would be much nicer to use
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// a mechanism like syntax_quote to ensure hygiene.
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pub fn core_macros() -> ~str {
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return
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~"pub mod macros {
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macro_rules! ignore (($($x:tt)*) => (()))
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macro_rules! error ( ($( $arg:expr ),+) => (
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log(::core::error, fmt!( $($arg),+ )) ))
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macro_rules! warn ( ($( $arg:expr ),+) => (
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log(::core::warn, fmt!( $($arg),+ )) ))
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macro_rules! info ( ($( $arg:expr ),+) => (
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log(::core::info, fmt!( $($arg),+ )) ))
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macro_rules! debug ( ($( $arg:expr ),+) => (
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log(::core::debug, fmt!( $($arg),+ )) ))
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macro_rules! fail(
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($msg: expr) => (
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::core::sys::begin_unwind($msg, file!().to_owned(), line!())
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);
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() => (
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fail!(~\"explicit failure\")
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)
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)
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macro_rules! fail_unless(
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($cond:expr) => {
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if !$cond {
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fail!(~\"assertion failed: \" + stringify!($cond))
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}
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}
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)
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macro_rules! condition (
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{ $c:ident: $in:ty -> $out:ty; } => {
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mod $c {
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fn key(_x: @::core::condition::Handler<$in,$out>) { }
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pub const cond : ::core::condition::Condition<$in,$out> =
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::core::condition::Condition {
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name: stringify!($c),
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key: key
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};
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}
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}
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)
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}";
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}
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// could cfg just be a borrowed pointer here?
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pub fn expand_crate(parse_sess: @mut parse::ParseSess,
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cfg: ast::crate_cfg, c: @crate) -> @crate {
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// adding *another* layer of indirection here so that the block
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// visitor can swap out one exts table for another for the duration
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// of the block. The cleaner alternative would be to thread the
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// exts table through the fold, but that would require updating
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// every method/element of AstFoldFns in fold.rs.
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let extsbox = @mut syntax_expander_table();
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let afp = default_ast_fold();
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let cx: ext_ctxt = mk_ctxt(parse_sess, cfg);
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let f_pre = @AstFoldFns {
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fold_expr: |expr,span,recur|
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expand_expr(extsbox, cx, expr, span, recur, afp.fold_expr),
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fold_mod: |modd,recur|
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expand_mod_items(extsbox, cx, modd, recur, afp.fold_mod),
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fold_item: |item,recur|
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expand_item(extsbox, cx, item, recur, afp.fold_item),
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fold_stmt: |stmt,span,recur|
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expand_stmt(extsbox, cx, stmt, span, recur, afp.fold_stmt),
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fold_block: |blk,span,recur|
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expand_block (extsbox, cx, blk, span, recur, afp.fold_block),
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new_span: |a| new_span(cx, a),
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.. *afp};
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let f = make_fold(f_pre);
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// add a bunch of macros as though they were placed at the
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// head of the program (ick).
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let attrs = ~[spanned {span:codemap::dummy_sp(),
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node: attribute_
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{style:attr_outer,
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value:spanned
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{node:meta_word(@~"macro_escape"),
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span:codemap::dummy_sp()},
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is_sugared_doc:false}}];
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let cm = match parse_item_from_source_str(~"<core-macros>",
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@core_macros(),
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cfg,attrs,
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parse_sess) {
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Some(item) => item,
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None => cx.bug(~"expected core macros to parse correctly")
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};
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// This is run for its side-effects on the expander env,
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// as it registers all the core macros as expanders.
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f.fold_item(cm);
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let res = @f.fold_crate(*c);
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return res;
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}
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#[cfg(test)]
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mod test {
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use super::*;
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use util::testing::check_equal;
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// make sure that fail! is present
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#[test] fn fail_exists_test () {
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let src = ~"fn main() { fail!(~\"something appropriately gloomy\");}";
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let sess = parse::new_parse_sess(None);
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let cfg = ~[];
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let crate_ast = parse::parse_crate_from_source_str(
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~"<test>",
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@src,
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cfg,sess);
|
|
expand_crate(sess,cfg,crate_ast);
|
|
}
|
|
|
|
// these following tests are quite fragile, in that they don't test what
|
|
// *kind* of failure occurs.
|
|
|
|
// make sure that macros can leave scope
|
|
#[should_fail]
|
|
#[test] fn macros_cant_escape_fns_test () {
|
|
let src = ~"fn bogus() {macro_rules! z (() => (3+4))}\
|
|
fn inty() -> int { z!() }";
|
|
let sess = parse::new_parse_sess(None);
|
|
let cfg = ~[];
|
|
let crate_ast = parse::parse_crate_from_source_str(
|
|
~"<test>",
|
|
@src,
|
|
cfg,sess);
|
|
// should fail:
|
|
expand_crate(sess,cfg,crate_ast);
|
|
}
|
|
|
|
// make sure that macros can leave scope for modules
|
|
#[should_fail]
|
|
#[test] fn macros_cant_escape_mods_test () {
|
|
let src = ~"mod foo {macro_rules! z (() => (3+4))}\
|
|
fn inty() -> int { z!() }";
|
|
let sess = parse::new_parse_sess(None);
|
|
let cfg = ~[];
|
|
let crate_ast = parse::parse_crate_from_source_str(
|
|
~"<test>",
|
|
@src,
|
|
cfg,sess);
|
|
// should fail:
|
|
expand_crate(sess,cfg,crate_ast);
|
|
}
|
|
|
|
// macro_escape modules shouldn't cause macros to leave scope
|
|
#[test] fn macros_can_escape_flattened_mods_test () {
|
|
let src = ~"#[macro_escape] mod foo {macro_rules! z (() => (3+4))}\
|
|
fn inty() -> int { z!() }";
|
|
let sess = parse::new_parse_sess(None);
|
|
let cfg = ~[];
|
|
let crate_ast = parse::parse_crate_from_source_str(
|
|
~"<test>",
|
|
@src,
|
|
cfg,sess);
|
|
// should fail:
|
|
expand_crate(sess,cfg,crate_ast);
|
|
}
|
|
|
|
#[test] fn core_macros_must_parse () {
|
|
let src = ~"
|
|
pub mod macros {
|
|
macro_rules! ignore (($($x:tt)*) => (()))
|
|
|
|
macro_rules! error ( ($( $arg:expr ),+) => (
|
|
log(::core::error, fmt!( $($arg),+ )) ))
|
|
}";
|
|
let sess = parse::new_parse_sess(None);
|
|
let cfg = ~[];
|
|
let item_ast = parse::parse_item_from_source_str(
|
|
~"<test>",
|
|
@src,
|
|
cfg,~[make_dummy_attr (@~"macro_escape")],sess);
|
|
match item_ast {
|
|
Some(_) => (), // success
|
|
None => fail!(~"expected this to parse")
|
|
}
|
|
}
|
|
|
|
#[test] fn test_contains_flatten (){
|
|
let attr1 = make_dummy_attr (@~"foo");
|
|
let attr2 = make_dummy_attr (@~"bar");
|
|
let escape_attr = make_dummy_attr (@~"macro_escape");
|
|
let attrs1 = ~[attr1, escape_attr, attr2];
|
|
check_equal (contains_macro_escape (attrs1),true);
|
|
let attrs2 = ~[attr1,attr2];
|
|
check_equal (contains_macro_escape (attrs2),false);
|
|
}
|
|
|
|
// make a "meta_word" outer attribute with the given name
|
|
fn make_dummy_attr(s: @~str) -> ast::attribute {
|
|
spanned {span:codemap::dummy_sp(),
|
|
node: attribute_
|
|
{style:attr_outer,
|
|
value:spanned
|
|
{node:meta_word(s),
|
|
span:codemap::dummy_sp()},
|
|
is_sugared_doc:false}}
|
|
}
|
|
|
|
}
|
|
|
|
// Local Variables:
|
|
// mode: rust
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// End:
|