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import driver::session;
import option::{none, some};
import std::map::hashmap;
import vec;
import syntax::ast::{crate, expr_, expr_mac, mac_invoc};
import syntax::fold::*;
import syntax::ext::base::*;
import syntax::parse::parser::parse_expr_from_source_str;
fn expand_expr(exts: hashmap<str, syntax_extension>, cx: ext_ctxt, e: expr_,
fld: ast_fold, orig: fn@(expr_, ast_fold) -> expr_) -> expr_ {
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(normal(ext)) {
let expanded = ext(cx, pth.span, args, body);
cx.bt_push(mac.span);
//keep going, outside-in
let fully_expanded = fld.fold_expr(expanded).node;
cx.bt_pop();
fully_expanded
}
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)
}
}
}
_ { cx.span_bug(mac.span, "naked syntactic bit") }
}
}
_ { orig(e, fld) }
};
}
// 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(sess: session::session, c: @crate) -> @crate {
let exts = syntax_expander_table();
let afp = default_ast_fold();
let cx: ext_ctxt = mk_ctxt(sess);
let f_pre =
{fold_expr: bind expand_expr(exts, cx, _, _, afp.fold_expr)
with *afp};
let f = make_fold(f_pre);
let cm = parse_expr_from_source_str("-", core_macros(),
sess.opts.cfg,
sess.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:
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