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// Copyright 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 bytes! extension. */
use ast;
use codemap::Span;
use ext::base::*;
use ext::base;
use ext::build::AstBuilder;
pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
-> Box<base::MacResult> {
cx.span_warn(sp, "`bytes!` is deprecated, use `b\"foo\"` literals instead");
cx.parse_sess.span_diagnostic.span_note(sp,
"see http://doc.rust-lang.org/rust.html#byte-and-byte-string-literals \
for documentation");
cx.parse_sess.span_diagnostic.span_note(sp,
"see https://github.com/rust-lang/rust/blob/master/src/etc/2014-06-rewrite-bytes-macros.py \
for an automated migration");
// Gather all argument expressions
let exprs = match get_exprs_from_tts(cx, sp, tts) {
None => return DummyResult::expr(sp),
Some(e) => e,
};
let mut bytes = Vec::new();
let mut err = false;
for expr in exprs.iter() {
match expr.node {
// expression is a literal
ast::ExprLit(lit) => match lit.node {
// string literal, push each byte to vector expression
ast::LitStr(ref s, _) => {
for byte in s.get().bytes() {
bytes.push(cx.expr_u8(expr.span, byte));
}
}
// u8 literal, push to vector expression
ast::LitInt(v, ast::UnsignedIntLit(ast::TyU8)) => {
if v > 0xFF {
cx.span_err(expr.span, "too large u8 literal in bytes!");
err = true;
} else {
bytes.push(cx.expr_u8(expr.span, v as u8));
}
}
// integer literal, push to vector expression
ast::LitInt(_, ast::UnsuffixedIntLit(ast::Minus)) => {
cx.span_err(expr.span, "negative integer literal in bytes!");
err = true;
}
ast::LitInt(v, ast::UnsuffixedIntLit(ast::Plus)) => {
if v > 0xFF {
cx.span_err(expr.span, "too large integer literal in bytes!");
err = true;
} else {
bytes.push(cx.expr_u8(expr.span, v as u8));
}
}
// char literal, push to vector expression
ast::LitChar(v) => {
if v.is_ascii() {
bytes.push(cx.expr_u8(expr.span, v as u8));
} else {
cx.span_err(expr.span, "non-ascii char literal in bytes!");
err = true;
}
}
_ => {
cx.span_err(expr.span, "unsupported literal in bytes!");
err = true;
}
},
_ => {
cx.span_err(expr.span, "non-literal in bytes!");
err = true;
}
}
}
// For some reason using quote_expr!() here aborts if we threw an error.
// I'm assuming that the end of the recursive parse tricks the compiler
// into thinking this is a good time to stop. But we'd rather keep going.
if err {
// Since the compiler will stop after the macro expansion phase anyway, we
// don't need type info, so we can just return a DummyResult
return DummyResult::expr(sp);
}
let e = cx.expr_vec_slice(sp, bytes);
let ty = cx.ty(sp, ast::TyVec(cx.ty_ident(sp, cx.ident_of("u8"))));
let lifetime = cx.lifetime(sp, cx.ident_of("'static").name);
let item = cx.item_static(sp,
cx.ident_of("BYTES"),
cx.ty_rptr(sp,
ty,
Some(lifetime),
ast::MutImmutable),
ast::MutImmutable,
e);
let e = cx.expr_block(cx.block(sp,
vec!(cx.stmt_item(sp, item)),
Some(cx.expr_ident(sp, cx.ident_of("BYTES")))));
MacExpr::new(e)
}
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