107 lines
3.8 KiB
Rust
107 lines
3.8 KiB
Rust
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*
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* The compiler code necessary to support the env! extension. Eventually this
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* should all get sucked into either the compiler syntax extension plugin
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* interface.
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*/
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::ext::base::*;
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use syntax::ext::base;
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use syntax::ext::build::AstBuilder;
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use syntax::parse::token;
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use std::env;
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pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
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-> Box<base::MacResult+'cx> {
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let var = match get_single_str_from_tts(cx, sp, tts, "option_env!") {
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None => return DummyResult::expr(sp),
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Some(v) => v
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};
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let e = match env::var(&var[..]) {
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Err(..) => {
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cx.expr_path(cx.path_all(sp,
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true,
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cx.std_path(&["option", "Option", "None"]),
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Vec::new(),
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vec!(cx.ty_rptr(sp,
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cx.ty_ident(sp,
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cx.ident_of("str")),
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Some(cx.lifetime(sp,
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cx.ident_of(
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"'static").name)),
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ast::Mutability::Immutable)),
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Vec::new()))
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}
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Ok(s) => {
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cx.expr_call_global(sp,
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cx.std_path(&["option", "Option", "Some"]),
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vec!(cx.expr_str(sp,
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token::intern_and_get_ident(
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&s[..]))))
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}
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};
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MacEager::expr(e)
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}
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pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
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-> Box<base::MacResult+'cx> {
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let mut exprs = match get_exprs_from_tts(cx, sp, tts) {
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Some(ref exprs) if exprs.is_empty() => {
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cx.span_err(sp, "env! takes 1 or 2 arguments");
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return DummyResult::expr(sp);
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}
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None => return DummyResult::expr(sp),
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Some(exprs) => exprs.into_iter()
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};
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let var = match expr_to_string(cx,
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exprs.next().unwrap(),
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"expected string literal") {
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None => return DummyResult::expr(sp),
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Some((v, _style)) => v
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};
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let msg = match exprs.next() {
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None => {
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token::intern_and_get_ident(&format!("environment variable `{}` \
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not defined",
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var))
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}
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Some(second) => {
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match expr_to_string(cx, second, "expected string literal") {
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None => return DummyResult::expr(sp),
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Some((s, _style)) => s
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}
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}
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};
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match exprs.next() {
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None => {}
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Some(_) => {
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cx.span_err(sp, "env! takes 1 or 2 arguments");
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return DummyResult::expr(sp);
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}
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}
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let e = match env::var(&var[..]) {
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Err(_) => {
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cx.span_err(sp, &msg);
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cx.expr_usize(sp, 0)
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}
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Ok(s) => cx.expr_str(sp, token::intern_and_get_ident(&s))
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};
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MacEager::expr(e)
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}
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