51 lines
1.5 KiB
Rust
51 lines
1.5 KiB
Rust
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/*
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* The compiler code necessary to support the #env extension. Eventually this
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* should all get sucked into either the compiler syntax extension plugin
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* interface.
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*/
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import std::vec;
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import std::istr;
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import std::option;
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import std::generic_os;
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import base::*;
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export expand_syntax_ext;
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fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
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_body: &option::t<istr>) -> @ast::expr {
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let args: [@ast::expr] =
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alt arg.node {
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ast::expr_vec(elts, _) { elts }
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_ {
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cx.span_fatal(sp, ~"#env requires arguments of the form `[...]`.")
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}
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};
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if vec::len::<@ast::expr>(args) != 1u {
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cx.span_fatal(sp, ~"malformed #env call");
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}
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// FIXME: if this was more thorough it would manufacture an
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// option::t<str> rather than just an maybe-empty string.
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let var = expr_to_str(cx, args[0], ~"#env requires a string");
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alt generic_os::getenv(var) {
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option::none. { ret make_new_str(cx, sp, ""); }
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option::some(s) {
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ret make_new_str(cx, sp, istr::to_estr(s));
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}
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}
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}
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fn make_new_str(cx: &ext_ctxt, sp: codemap::span, s: str) -> @ast::expr {
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ret make_new_lit(cx, sp, ast::lit_str(istr::from_estr(s), ast::sk_rc));
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}
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//
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// Local Variables:
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// mode: rust
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
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// End:
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//
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