| // The compiler code necessary to support the env! extension. Eventually this |
| // should all get sucked into either the compiler syntax extension plugin |
| // interface. |
| // |
| |
| use syntax::ast::{self, Ident, GenericArg}; |
| use syntax::ext::base::{self, *}; |
| use syntax::symbol::{kw, sym, Symbol}; |
| use syntax_pos::Span; |
| use syntax::tokenstream; |
| |
| use std::env; |
| |
| pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: &[tokenstream::TokenTree]) |
| -> Box<dyn base::MacResult + 'cx> { |
| let var = match get_single_str_from_tts(cx, sp, tts, "option_env!") { |
| None => return DummyResult::expr(sp), |
| Some(v) => v, |
| }; |
| |
| let sp = sp.apply_mark(cx.current_expansion.id); |
| let e = match env::var(&*var.as_str()) { |
| Err(..) => { |
| let lt = cx.lifetime(sp, Ident::with_empty_ctxt(kw::StaticLifetime)); |
| cx.expr_path(cx.path_all(sp, |
| true, |
| cx.std_path(&[sym::option, sym::Option, sym::None]), |
| vec![GenericArg::Type(cx.ty_rptr(sp, |
| cx.ty_ident(sp, |
| Ident::with_empty_ctxt(sym::str)), |
| Some(lt), |
| ast::Mutability::Immutable))], |
| vec![])) |
| } |
| Ok(s) => { |
| cx.expr_call_global(sp, |
| cx.std_path(&[sym::option, sym::Option, sym::Some]), |
| vec![cx.expr_str(sp, Symbol::intern(&s))]) |
| } |
| }; |
| MacEager::expr(e) |
| } |
| |
| pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: &[tokenstream::TokenTree]) |
| -> Box<dyn base::MacResult + 'cx> { |
| let mut exprs = match get_exprs_from_tts(cx, sp, tts) { |
| Some(ref exprs) if exprs.is_empty() => { |
| cx.span_err(sp, "env! takes 1 or 2 arguments"); |
| return DummyResult::expr(sp); |
| } |
| None => return DummyResult::expr(sp), |
| Some(exprs) => exprs.into_iter(), |
| }; |
| |
| let var = match expr_to_string(cx, exprs.next().unwrap(), "expected string literal") { |
| None => return DummyResult::expr(sp), |
| Some((v, _style)) => v, |
| }; |
| let msg = match exprs.next() { |
| None => Symbol::intern(&format!("environment variable `{}` not defined", var)), |
| Some(second) => { |
| match expr_to_string(cx, second, "expected string literal") { |
| None => return DummyResult::expr(sp), |
| Some((s, _style)) => s, |
| } |
| } |
| }; |
| |
| if exprs.next().is_some() { |
| cx.span_err(sp, "env! takes 1 or 2 arguments"); |
| return DummyResult::expr(sp); |
| } |
| |
| let e = match env::var(&*var.as_str()) { |
| Err(_) => { |
| cx.span_err(sp, &msg.as_str()); |
| return DummyResult::expr(sp); |
| } |
| Ok(s) => cx.expr_str(sp, Symbol::intern(&s)), |
| }; |
| MacEager::expr(e) |
| } |