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// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*
* The compiler code necessary to support the env! extension. Eventually this
* should all get sucked into either the compiler syntax extension plugin
* interface.
*/
use ast;
use codemap::Span;
use ext::base::*;
use ext::base;
use ext::build::AstBuilder;
use std::os;
pub fn expand_option_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::token_tree])
-> base::MacResult {
let var = get_single_str_from_tts(cx, sp, tts, "option_env!");
let e = match os::getenv(var) {
None => quote_expr!(cx, ::std::option::None::<&'static str>),
Some(s) => quote_expr!(cx, ::std::option::Some($s))
};
MRExpr(e)
}
pub fn expand_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::token_tree])
-> base::MacResult {
let exprs = get_exprs_from_tts(cx, sp, tts);
if exprs.len() == 0 {
cx.span_fatal(sp, "env! takes 1 or 2 arguments");
}
let (var, _var_str_style) = expr_to_str(cx, exprs[0], "expected string literal");
let msg = match exprs.len() {
1 => format!("Environment variable {} not defined", var).to_managed(),
2 => {
let (s, _style) = expr_to_str(cx, exprs[1], "expected string literal");
s
}
_ => cx.span_fatal(sp, "env! takes 1 or 2 arguments")
};
let e = match os::getenv(var) {
None => cx.span_fatal(sp, msg),
Some(s) => cx.expr_str(sp, s.to_managed())
};
MRExpr(e)
}
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