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import driver::session;
import driver::session::session;
import std::map::hashmap;
import front::attr;
import syntax::ast::{crate, expr_, expr_mac, mac_invoc};
import syntax::fold::*;
import syntax::ext::base::*;
import syntax::ext::qquote::{qq_helper};
import syntax::parse::parser;
import syntax::parse::parser::parse_expr_from_source_str;
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.node.idents) > 0u);
let extname = pth.node.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, pth.span, args, body);
let info = {call_site: s,
callie: {name: extname, span: exp_sp}};
cx.bt_push(expanded_from(info));
//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, pth.span, args, body);
exts.insert(named_extension.ident, named_extension.ext);
(ast::expr_rec([], none), s)
}
}
}
_ { 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 = vec::flat_map(module.items) {|item|
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 { items }
some(normal(_)) | some(macro_defining(_)) {
cx.span_err(
attr.span,
#fmt["%s cannot be used as a decorator", mname]);
items
}
some(item_decorator(dec_fn)) {
dec_fn(cx, attr.span, attr.node.value, items)
}
}
}
};
ret {items: new_items with module};
}
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: 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: parser::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: bind expand_expr(exts, cx, _, _, _, afp.fold_expr),
fold_mod: bind expand_mod_items(exts, cx, _, _, afp.fold_mod),
new_span: bind new_span(cx, _)
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:
|
