(index<- ) ./libsyntax/ext/env.rs
git branch: * master 5200215 auto merge of #14035 : alexcrichton/rust/experimental, r=huonw
modified: Fri May 9 13:02:28 2014
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
4 //
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10
11 /*
12 * The compiler code necessary to support the env! extension. Eventually this
13 * should all get sucked into either the compiler syntax extension plugin
14 * interface.
15 */
16
17 use ast;
18 use codemap::Span;
19 use ext::base::*;
20 use ext::base;
21 use ext::build::AstBuilder;
22 use parse::token;
23
24 use std::os;
25
26 pub fn expand_option_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
27 -> Box<base::MacResult> {
28 let var = match get_single_str_from_tts(cx, sp, tts, "option_env!") {
29 None => return DummyResult::expr(sp),
30 Some(v) => v
31 };
32
33 let e = match os::getenv(var.as_slice()) {
34 None => {
35 cx.expr_path(cx.path_all(sp,
36 true,
37 vec!(cx.ident_of("std"),
38 cx.ident_of("option"),
39 cx.ident_of("None")),
40 Vec::new(),
41 vec!(cx.ty_rptr(sp,
42 cx.ty_ident(sp,
43 cx.ident_of("str")),
44 Some(cx.lifetime(sp,
45 cx.ident_of(
46 "static").name)),
47 ast::MutImmutable))))
48 }
49 Some(s) => {
50 cx.expr_call_global(sp,
51 vec!(cx.ident_of("std"),
52 cx.ident_of("option"),
53 cx.ident_of("Some")),
54 vec!(cx.expr_str(sp,
55 token::intern_and_get_ident(
56 s))))
57 }
58 };
59 MacExpr::new(e)
60 }
61
62 pub fn expand_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
63 -> Box<base::MacResult> {
64 let exprs = match get_exprs_from_tts(cx, sp, tts) {
65 Some(ref exprs) if exprs.len() == 0 => {
66 cx.span_err(sp, "env! takes 1 or 2 arguments");
67 return DummyResult::expr(sp);
68 }
69 None => return DummyResult::expr(sp),
70 Some(exprs) => exprs
71 };
72
73 let var = match expr_to_str(cx,
74 *exprs.get(0),
75 "expected string literal") {
76 None => return DummyResult::expr(sp),
77 Some((v, _style)) => v
78 };
79 let msg = match exprs.len() {
80 1 => {
81 token::intern_and_get_ident(format!("environment variable `{}` \
82 not defined",
83 var))
84 }
85 2 => {
86 match expr_to_str(cx, *exprs.get(1), "expected string literal") {
87 None => return DummyResult::expr(sp),
88 Some((s, _style)) => s
89 }
90 }
91 _ => {
92 cx.span_err(sp, "env! takes 1 or 2 arguments");
93 return DummyResult::expr(sp);
94 }
95 };
96
97 let e = match os::getenv(var.get()) {
98 None => {
99 cx.span_err(sp, msg.get());
100 cx.expr_uint(sp, 0)
101 }
102 Some(s) => cx.expr_str(sp, token::intern_and_get_ident(s))
103 };
104 MacExpr::new(e)
105 }