1 // The compiler code necessary to support the env! extension. Eventually this
2 // should all get sucked into either the compiler syntax extension plugin
6 use syntax::ast::{self, Ident, GenericArg};
7 use syntax_expand::base::{self, *};
8 use syntax::symbol::{kw, sym, Symbol};
10 use syntax::tokenstream::TokenStream;
14 pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
17 -> Box<dyn base::MacResult + 'cx> {
18 let var = match get_single_str_from_tts(cx, sp, tts, "option_env!") {
19 None => return DummyResult::any(sp),
23 let sp = cx.with_def_site_ctxt(sp);
24 let e = match env::var(&var.as_str()) {
26 let lt = cx.lifetime(sp, Ident::new(kw::StaticLifetime, sp));
27 cx.expr_path(cx.path_all(sp,
29 cx.std_path(&[sym::option, sym::Option, sym::None]),
30 vec![GenericArg::Type(cx.ty_rptr(sp,
32 Ident::new(sym::str, sp)),
34 ast::Mutability::Immutable))],
38 cx.expr_call_global(sp,
39 cx.std_path(&[sym::option, sym::Option, sym::Some]),
40 vec![cx.expr_str(sp, Symbol::intern(&s))])
46 pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
49 -> Box<dyn base::MacResult + 'cx> {
50 let mut exprs = match get_exprs_from_tts(cx, sp, tts) {
51 Some(ref exprs) if exprs.is_empty() => {
52 cx.span_err(sp, "env! takes 1 or 2 arguments");
53 return DummyResult::any(sp);
55 None => return DummyResult::any(sp),
56 Some(exprs) => exprs.into_iter(),
59 let var = match expr_to_string(cx, exprs.next().unwrap(), "expected string literal") {
60 None => return DummyResult::any(sp),
61 Some((v, _style)) => v,
63 let msg = match exprs.next() {
64 None => Symbol::intern(&format!("environment variable `{}` not defined", var)),
66 match expr_to_string(cx, second, "expected string literal") {
67 None => return DummyResult::any(sp),
68 Some((s, _style)) => s,
73 if exprs.next().is_some() {
74 cx.span_err(sp, "env! takes 1 or 2 arguments");
75 return DummyResult::any(sp);
78 let e = match env::var(&*var.as_str()) {
80 cx.span_err(sp, &msg.as_str());
81 return DummyResult::any(sp);
83 Ok(s) => cx.expr_str(sp, Symbol::intern(&s)),