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::ext::base::{self, *};
8 use syntax::ext::build::AstBuilder;
9 use syntax::symbol::{keywords, Symbol};
11 use syntax::tokenstream;
15 pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
17 tts: &[tokenstream::TokenTree])
18 -> Box<dyn base::MacResult + 'cx> {
19 let var = match get_single_str_from_tts(cx, sp, tts, "option_env!") {
20 None => return DummyResult::expr(sp),
24 let sp = sp.apply_mark(cx.current_expansion.mark);
25 let e = match env::var(&*var.as_str()) {
27 let lt = cx.lifetime(sp, keywords::StaticLifetime.ident());
28 cx.expr_path(cx.path_all(sp,
30 cx.std_path(&["option", "Option", "None"]),
31 vec![GenericArg::Type(cx.ty_rptr(sp,
32 cx.ty_ident(sp, Ident::from_str("str")),
34 ast::Mutability::Immutable))],
38 cx.expr_call_global(sp,
39 cx.std_path(&["option", "Option", "Some"]),
40 vec![cx.expr_str(sp, Symbol::intern(&s))])
46 pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
48 tts: &[tokenstream::TokenTree])
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::expr(sp);
55 None => return DummyResult::expr(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::expr(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::expr(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::expr(sp);
78 let e = match env::var(&*var.as_str()) {
80 cx.span_err(sp, &msg.as_str());
81 return DummyResult::expr(sp);
83 Ok(s) => cx.expr_str(sp, Symbol::intern(&s)),