use ast;
use codemap::Span;
use ext::base::*;
use ext::base;
use ext::build::AstBuilder;
use parse::token;
use std::env;
pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
-> Box<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 e = match env::var(&var[..]) {
Err(..) => {
cx.expr_path(cx.path_all(sp,
true,
cx.std_path(&["option", "Option", "None"]),
Vec::new(),
vec!(cx.ty_rptr(sp,
cx.ty_ident(sp,
cx.ident_of("str")),
Some(cx.lifetime(sp,
cx.ident_of(
"'static").name)),
ast::Mutability::Immutable)),
Vec::new()))
}
Ok(s) => {
cx.expr_call_global(sp,
cx.std_path(&["option", "Option", "Some"]),
vec!(cx.expr_str(sp,
token::intern_and_get_ident(
&s[..]))))
}
};
MacEager::expr(e)
}
pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
-> Box<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 => {
token::intern_and_get_ident(&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
}
}
};
match exprs.next() {
None => {}
Some(_) => {
cx.span_err(sp, "env! takes 1 or 2 arguments");
return DummyResult::expr(sp);
}
}
let e = match env::var(&var[..]) {
Err(_) => {
cx.span_err(sp, &msg);
cx.expr_usize(sp, 0)
}
Ok(s) => cx.expr_str(sp, token::intern_and_get_ident(&s))
};
MacEager::expr(e)
}