rust/src/libsyntax/ext/bytes.rs

80 lines
2.8 KiB
Rust

// 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;
use std::char;
use std::vec_ng::Vec;
pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree]) -> base::MacResult {
// Gather all argument expressions
let exprs = match get_exprs_from_tts(cx, sp, tts) {
None => return MacResult::dummy_expr(sp),
Some(e) => e,
};
let mut bytes = Vec::new();
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::LitUint(v, ast::TyU8) => {
if v > 0xFF {
cx.span_err(expr.span, "too large u8 literal in bytes!")
} else {
bytes.push(cx.expr_u8(expr.span, v as u8));
}
}
// integer literal, push to vector expression
ast::LitIntUnsuffixed(v) => {
if v > 0xFF {
cx.span_err(expr.span, "too large integer literal in bytes!")
} else if v < 0 {
cx.span_err(expr.span, "negative integer literal in bytes!")
} else {
bytes.push(cx.expr_u8(expr.span, v as u8));
}
}
// char literal, push to vector expression
ast::LitChar(v) => {
if char::from_u32(v).unwrap().is_ascii() {
bytes.push(cx.expr_u8(expr.span, v as u8));
} else {
cx.span_err(expr.span, "non-ascii char literal in bytes!")
}
}
_ => cx.span_err(expr.span, "unsupported literal in bytes!")
},
_ => cx.span_err(expr.span, "non-literal in bytes!")
}
}
let e = cx.expr_vec_slice(sp, bytes);
MRExpr(e)
}