358 lines
13 KiB
Rust
358 lines
13 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 codemap::{span, ExpandedFrom};
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use ext::base::*;
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use fold::*;
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use parse::{parser, parse_expr_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 std::oldmap::HashMap;
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pub fn expand_expr(exts: HashMap<~str, SyntaxExtension>, 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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match exts.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(NormalTT(SyntaxExpanderTT{expander: exp,
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span: exp_sp})) => {
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cx.bt_push(ExpandedFrom({call_site: s,
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callie: {name: *extname, span: exp_sp}}));
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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(exts: HashMap<~str, SyntaxExtension>, 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 = match attr.node.value.node {
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ast::meta_word(ref n) => (*n),
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ast::meta_name_value(ref n, _) => (*n),
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ast::meta_list(ref n, _) => (*n)
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};
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match exts.find(&mname) {
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None | Some(NormalTT(_)) | Some(ItemTT(*)) => items,
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Some(ItemDecorator(dec_fn)) => {
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cx.bt_push(ExpandedFrom({call_site: attr.span,
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callie: {name: copy mname,
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span: None}}));
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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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}
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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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// When we enter a module, record it, for the sake of `module!`
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pub fn expand_item(exts: HashMap<~str, SyntaxExtension>,
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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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let is_mod = match it.node {
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ast::item_mod(_) | ast::item_foreign_mod(_) => true,
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_ => false
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};
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let maybe_it = match it.node {
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ast::item_mac(*) => expand_item_mac(exts, 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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if is_mod { cx.mod_push(it.ident); }
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let ret_val = orig(it, fld);
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if is_mod { cx.mod_pop(); }
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return ret_val;
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}
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None => return None
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}
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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(exts: HashMap<~str, SyntaxExtension>,
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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 exts.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(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({call_site: it.span,
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callie: {name: *extname,
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span: (*expand).span}}));
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((*expand).expander)(cx, it.span, tts)
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}
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Some(ItemTT(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({call_site: it.span,
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callie: {name: *extname,
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span: (*expand).span}}));
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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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exts.insert((*mdef).name, (*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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pub fn expand_stmt(exts: HashMap<~str, SyntaxExtension>, 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 exts.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(NormalTT(
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SyntaxExpanderTT{expander: exp, span: exp_sp})) => {
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cx.bt_push(ExpandedFrom(
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{call_site: sp, callie: {name: *extname, span: exp_sp}}));
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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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return (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 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 terrible kludge to inject some macros into
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// the default compilation environment. When the macro-definition system
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// is substantially more mature, these should move from here, into a
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// compiled part of libcore at very least.
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pub fn core_macros() -> ~str {
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return
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~"{
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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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pub fn expand_crate(parse_sess: parse::parse_sess,
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cfg: ast::crate_cfg, c: @crate) -> @crate {
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let exts = 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: |a,b,c| expand_expr(exts, cx, a, b, c, afp.fold_expr),
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fold_mod: |a,b| expand_mod_items(exts, cx, a, b, afp.fold_mod),
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fold_item: |a,b| expand_item(exts, cx, a, b, afp.fold_item),
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fold_stmt: |a,b,c| expand_stmt(exts, cx, a, b, c, afp.fold_stmt),
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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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let cm = parse_expr_from_source_str(~"<core-macros>",
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@core_macros(),
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cfg,
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parse_sess);
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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_expr(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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// Local Variables:
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// mode: rust
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// End:
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