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import core::{vec, 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_def = {ident: str, ext: syntax_extension};
type macro_definer =
fn@(ext_ctxt, span, @ast::expr, option::t<str>) -> macro_def;
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> {
let 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));
syntax_expanders.insert("concat_idents",
normal(ext::concat_idents::expand_syntax_ext));
syntax_expanders.insert("ident_to_str",
normal(ext::ident_to_str::expand_syntax_ext));
syntax_expanders.insert("log_syntax",
normal(ext::log_syntax::expand_syntax_ext));
ret syntax_expanders;
}
obj ext_ctxt(sess: @session,
crate_file_name_hack: str,
mutable backtrace: codemap::opt_span) {
fn crate_file_name() -> str { ret crate_file_name_hack; }
fn session() -> @session { ret sess; }
fn print_backtrace() { }
fn backtrace() -> codemap::opt_span { ret backtrace; }
fn bt_push(sp: span) {
backtrace =
codemap::os_some(@{lo: sp.lo,
hi: sp.hi,
expanded_from: backtrace});
}
fn bt_pop() {
alt backtrace {
codemap::os_some(@{expanded_from: pre, _}) {
let tmp = pre;
backtrace = tmp;
}
_ { self.bug("tried to pop without a push"); }
}
}
fn span_fatal(sp: span, msg: str) -> ! {
self.print_backtrace();
sess.span_fatal(sp, msg);
}
fn span_err(sp: span, msg: str) {
self.print_backtrace();
sess.span_err(sp, msg);
}
fn span_unimpl(sp: span, msg: str) -> ! {
self.print_backtrace();
sess.span_unimpl(sp, msg);
}
fn span_bug(sp: span, msg: str) -> ! {
self.print_backtrace();
sess.span_bug(sp, msg);
}
fn bug(msg: str) -> ! { self.print_backtrace(); sess.bug(msg); }
fn next_id() -> ast::node_id { ret sess.next_node_id(); }
}
fn mk_ctxt(sess: session) -> ext_ctxt {
// 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.
let crate_file_name_hack = sess.get_codemap().files[0].name;
ret ext_ctxt(@sess, crate_file_name_hack, codemap::os_none);
}
fn expr_to_str(cx: ext_ctxt, expr: @ast::expr, error: str) -> str {
alt expr.node {
ast::expr_lit(l) {
alt l.node {
ast::lit_str(s) { ret s; }
_ { cx.span_fatal(l.span, error); }
}
}
_ { cx.span_fatal(expr.span, error); }
}
}
fn expr_to_ident(cx: ext_ctxt, expr: @ast::expr, error: str) -> ast::ident {
alt expr.node {
ast::expr_path(p) {
if vec::len(p.node.types) > 0u || vec::len(p.node.idents) != 1u {
cx.span_fatal(expr.span, error);
} else { ret p.node.idents[0]; }
}
_ { cx.span_fatal(expr.span, error); }
}
}
fn make_new_lit(cx: ext_ctxt, sp: codemap::span, lit: ast::lit_) ->
@ast::expr {
let sp_lit = @{node: lit, span: sp};
ret @{id: cx.next_id(), node: ast::expr_lit(sp_lit), span: sp};
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//
|
