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import std::ivec;
import std::option;
import std::map::hashmap;
import driver::session::session;
import codemap::span;
import std::map::new_str_hash;
import codemap;
type syntax_expander =
fn(&ext_ctxt, span, &(@ast::expr)[], option::t[str]) -> @ast::expr;
type macro_definer = fn(&ext_ctxt, span, &(@ast::expr)[],
option::t[str]) -> tup(str, syntax_extension);
tag syntax_extension {
normal(syntax_expander);
macro_defining(macro_definer);
}
// A temporary hard-coded map of methods for expanding syntax extension
// AST nodes into full ASTs
fn syntax_expander_table() -> hashmap[str, syntax_extension] {
auto syntax_expanders = new_str_hash[syntax_extension]();
syntax_expanders.insert("fmt", normal(ext::fmt::expand_syntax_ext));
syntax_expanders.insert("env", normal(ext::env::expand_syntax_ext));
syntax_expanders.insert("macro",
macro_defining(ext::simplext::add_new_extension));
ret syntax_expanders;
}
type span_msg_fn = fn(span, str) -> ! ;
type next_id_fn = fn() -> ast::node_id ;
// Provides a limited set of services necessary for syntax extensions
// to do their thing
type ext_ctxt =
rec(str crate_file_name_hack,
span_msg_fn span_fatal,
span_msg_fn span_unimpl,
next_id_fn next_id);
fn mk_ctxt(&session sess) -> ext_ctxt {
fn ext_span_fatal_(&session sess, span sp, str msg) -> ! {
sess.span_err(sp, msg);
fail;
}
auto ext_span_fatal = bind ext_span_fatal_(sess, _, _);
fn ext_span_unimpl_(&session sess, span sp, str msg) -> ! {
sess.span_err(sp, "unimplemented " + msg);
fail;
}
// FIXME: Some extensions work by building ASTs with paths to functions
// they need to call at runtime. As those functions live in the std crate,
// the paths are prefixed with "std::". Unfortunately, these paths can't
// work for code called from inside the stdard library, so here we pass
// the extensions the file name of the crate being compiled so they can
// use it to guess whether paths should be prepended with "std::". This is
// super-ugly and needs a better solution.
auto crate_file_name_hack = sess.get_codemap().files.(0).name;
auto ext_span_unimpl = bind ext_span_unimpl_(sess, _, _);
fn ext_next_id_(&session sess) -> ast::node_id {
ret sess.next_node_id(); // temporary, until bind works better
}
auto ext_next_id = bind ext_next_id_(sess);
ret rec(crate_file_name_hack=crate_file_name_hack,
span_fatal=ext_span_fatal,
span_unimpl=ext_span_unimpl,
next_id=ext_next_id);
}
fn expr_to_str(&ext_ctxt cx, @ast::expr expr, str error) -> str {
alt (expr.node) {
case (ast::expr_lit(?l)) {
alt (l.node) {
case (ast::lit_str(?s, _)) { ret s; }
case (_) { cx.span_fatal(l.span, error); }
}
}
case (_) { cx.span_fatal(expr.span, error); }
}
}
fn expr_to_ident(&ext_ctxt cx, @ast::expr expr, str error) -> ast::ident {
alt(expr.node) {
case (ast::expr_path(?p)) {
if (ivec::len(p.node.types) > 0u
|| ivec::len(p.node.idents) != 1u) {
cx.span_fatal(expr.span, error);
} else {
ret p.node.idents.(0);
}
}
case (_) {
cx.span_fatal(expr.span, error);
}
}
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End:
//
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