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|
import std::map::hashmap;
import ast::{crate, expr_, expr_mac, mac_invoc, mac_invoc_tt,
tt_delim, tt_flat, item_mac};
import fold::*;
import ext::base::*;
import ext::qquote::{qq_helper};
import parse::{parser, parse_expr_from_source_str, new_parser_from_tt};
import codemap::{span, expanded_from};
fn expand_expr(exts: hashmap<str, syntax_extension>, cx: ext_ctxt,
e: expr_, s: span, fld: ast_fold,
orig: fn@(expr_, span, ast_fold) -> (expr_, span))
-> (expr_, span)
{
ret alt e {
expr_mac(mac) {
alt mac.node {
mac_invoc(pth, args, body) {
assert (vec::len(pth.idents) > 0u);
let extname = pth.idents[0];
alt exts.find(*extname) {
none {
cx.span_fatal(pth.span,
#fmt["macro undefined: '%s'", *extname])
}
some(item_decorator(_)) {
cx.span_fatal(
pth.span,
#fmt["%s can only be used as a decorator", *extname]);
}
some(normal({expander: exp, span: exp_sp})) {
let expanded = exp(cx, mac.span, args, body);
cx.bt_push(expanded_from({call_site: s,
callie: {name: *extname, span: exp_sp}}));
//keep going, outside-in
let fully_expanded = fld.fold_expr(expanded).node;
cx.bt_pop();
(fully_expanded, s)
}
some(macro_defining(ext)) {
let named_extension = ext(cx, mac.span, args, body);
exts.insert(*named_extension.ident, named_extension.ext);
(ast::expr_rec(~[], none), s)
}
some(expr_tt(_)) {
cx.span_fatal(pth.span,
#fmt["this tt-style macro should be \
invoked '%s!{...}'", *extname])
}
some(item_tt(*)) {
cx.span_fatal(pth.span,
"cannot use item macros in this context");
}
}
}
mac_invoc_tt(pth, tts) {
assert (vec::len(pth.idents) == 1u);
let extname = pth.idents[0];
alt exts.find(*extname) {
none {
cx.span_fatal(pth.span,
#fmt["macro undefined: '%s'", *extname])
}
some(expr_tt({expander: exp, span: exp_sp})) {
let expanded = alt exp(cx, mac.span, tts) {
mr_expr(e) { e }
_ { cx.span_fatal(
pth.span, #fmt["non-expr macro in expr pos: %s",
*extname]) }
};
cx.bt_push(expanded_from({call_site: s,
callie: {name: *extname, span: exp_sp}}));
//keep going, outside-in
let fully_expanded = fld.fold_expr(expanded).node;
cx.bt_pop();
(fully_expanded, s)
}
_ {
cx.span_fatal(pth.span,
#fmt["'%s' is not a tt-style macro",
*extname])
}
}
}
_ { cx.span_bug(mac.span, "naked syntactic bit") }
}
}
_ { orig(e, s, fld) }
};
}
fn expand_mod_items(exts: hashmap<str, syntax_extension>, cx: ext_ctxt,
module: ast::_mod, fld: ast_fold,
orig: fn@(ast::_mod, ast_fold) -> ast::_mod)
-> ast::_mod
{
// Fold the contents first:
let module = orig(module, fld);
// For each item, look through the attributes. If any of them are
// decorated with "item decorators", then use that function to transform
// the item into a new set of items.
let new_items = do vec::flat_map(module.items) |item| {
do vec::foldr(item.attrs, ~[item]) |attr, items| {
let mname = alt attr.node.value.node {
ast::meta_word(n) { n }
ast::meta_name_value(n, _) { n }
ast::meta_list(n, _) { n }
};
alt exts.find(*mname) {
none | some(normal(_)) | some(macro_defining(_))
| some(expr_tt(_)) | some(item_tt(*)) {
items
}
some(item_decorator(dec_fn)) {
dec_fn(cx, attr.span, attr.node.value, items)
}
}
}
};
ret {items: new_items with module};
}
/* record module we enter for `#mod` */
fn expand_item(exts: hashmap<str, syntax_extension>,
cx: ext_ctxt, &&it: @ast::item, fld: ast_fold,
orig: fn@(&&@ast::item, ast_fold) -> option<@ast::item>)
-> option<@ast::item>
{
let is_mod = alt it.node {
ast::item_mod(_) | ast::item_foreign_mod(_) {true}
_ {false}
};
let maybe_it = alt it.node {
ast::item_mac(*) {
expand_item_mac(exts, cx, it, fld)
}
_ { some(it) }
};
alt maybe_it {
some(it) {
if is_mod { cx.mod_push(it.ident); }
let ret_val = orig(it, fld);
if is_mod { cx.mod_pop(); }
ret ret_val;
}
none { ret none; }
}
}
fn expand_item_mac(exts: hashmap<str, syntax_extension>,
cx: ext_ctxt, &&it: @ast::item,
fld: ast_fold) -> option<@ast::item> {
alt it.node {
item_mac({node: mac_invoc_tt(pth, tts), span}) {
let extname = pth.idents[0];
alt exts.find(*extname) {
none {
cx.span_fatal(pth.span,
#fmt("macro undefined: '%s'", *extname))
}
some(item_tt(expand)) {
let expanded = expand.expander(cx, it.span, it.ident, tts);
cx.bt_push(expanded_from({call_site: it.span,
callie: {name: *extname,
span: expand.span}}));
let maybe_it = alt expanded {
mr_item(it) { fld.fold_item(it) }
mr_expr(e) { cx.span_fatal(pth.span,
"expr macro in item position: " +
*extname) }
mr_def(mdef) {
exts.insert(*mdef.ident, mdef.ext);
none
}
};
cx.bt_pop();
ret maybe_it
}
_ { cx.span_fatal(it.span,
#fmt("%s is not a legal here", *extname)) }
}
}
_ {
cx.span_bug(it.span, "invalid item macro invocation");
}
}
}
fn new_span(cx: ext_ctxt, sp: span) -> span {
/* this discards information in the case of macro-defining macros */
ret {lo: sp.lo, hi: sp.hi, expn_info: cx.backtrace()};
}
// FIXME (#2247): this is a terrible kludge to inject some macros into
// the default compilation environment. When the macro-definition system
// is substantially more mature, these should move from here, into a
// compiled part of libcore at very least.
fn core_macros() -> str {
ret
"{
#macro([#error[f, ...], log(core::error, #fmt[f, ...])]);
#macro([#warn[f, ...], log(core::warn, #fmt[f, ...])]);
#macro([#info[f, ...], log(core::info, #fmt[f, ...])]);
#macro([#debug[f, ...], log(core::debug, #fmt[f, ...])]);
}";
}
fn expand_crate(parse_sess: parse::parse_sess,
cfg: ast::crate_cfg, c: @crate) -> @crate {
let exts = syntax_expander_table();
let afp = default_ast_fold();
let cx: ext_ctxt = mk_ctxt(parse_sess, cfg);
let f_pre =
@{fold_expr: |a,b,c| expand_expr(exts, cx, a, b, c, afp.fold_expr),
fold_mod: |a,b| expand_mod_items(exts, cx, a, b, afp.fold_mod),
fold_item: |a,b| expand_item(exts, cx, a, b, afp.fold_item),
new_span: |a|new_span(cx, a)
with *afp};
let f = make_fold(f_pre);
let cm = parse_expr_from_source_str("<core-macros>",
@core_macros(),
cfg,
parse_sess);
// This is run for its side-effects on the expander env,
// as it registers all the core macros as expanders.
f.fold_expr(cm);
let res = @f.fold_crate(*c);
ret res;
}
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
|
