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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: @ExtCtxt, sp: span, tts: &[ast::token_tree]) -> base::MacResult {
// Gather all argument expressions
let exprs = get_exprs_from_tts(cx, sp, tts);
let mut bytes = ~[];
for expr in exprs.iter() {
match expr.node {
// expression is a literal
ast::expr_lit(lit) => match lit.node {
// string literal, push each byte to vector expression
ast::lit_str(s) => {
for byte in s.byte_iter() {
bytes.push(cx.expr_u8(sp, byte));
}
}
// u8 literal, push to vector expression
ast::lit_uint(v, ast::ty_u8) => {
if v > 0xFF {
cx.span_err(sp, "Too large u8 literal in bytes!")
} else {
bytes.push(cx.expr_u8(sp, v as u8));
}
}
// integer literal, push to vector expression
ast::lit_int_unsuffixed(v) => {
if v > 0xFF {
cx.span_err(sp, "Too large integer literal in bytes!")
} else if v < 0 {
cx.span_err(sp, "Negative integer literal in bytes!")
} else {
bytes.push(cx.expr_u8(sp, v as u8));
}
}
// char literal, push to vector expression
ast::lit_int(v, ast::ty_char) => {
if (v as char).is_ascii() {
bytes.push(cx.expr_u8(sp, v as u8));
} else {
cx.span_err(sp, "Non-ascii char literal in bytes!")
}
}
_ => cx.span_err(sp, "Unsupported literal in bytes!")
},
_ => cx.span_err(sp, "Non-literal in bytes!")
}
}
let e = cx.expr_vec_slice(sp, bytes);
MRExpr(e)
}
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