rust/src/libsyntax/ext/concat.rs
Jakub Bukaj eb01b17b06 Complete the removal of ty_nil, ast::LitNil, ast::TyBot and ast::TyUniq
[breaking-change]

This will break any uses of macros that assumed () being a valid literal.
2014-11-16 14:23:15 +01:00

67 lines
2.5 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.
use ast;
use codemap;
use ext::base;
use ext::build::AstBuilder;
use parse::token;
use std::string::String;
pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
sp: codemap::Span,
tts: &[ast::TokenTree])
-> Box<base::MacResult+'static> {
let es = match base::get_exprs_from_tts(cx, sp, tts) {
Some(e) => e,
None => return base::DummyResult::expr(sp)
};
let mut accumulator = String::new();
for e in es.into_iter() {
match e.node {
ast::ExprLit(ref lit) => {
match lit.node {
ast::LitStr(ref s, _) |
ast::LitFloat(ref s, _) |
ast::LitFloatUnsuffixed(ref s) => {
accumulator.push_str(s.get());
}
ast::LitChar(c) => {
accumulator.push(c);
}
ast::LitInt(i, ast::UnsignedIntLit(_)) |
ast::LitInt(i, ast::SignedIntLit(_, ast::Plus)) |
ast::LitInt(i, ast::UnsuffixedIntLit(ast::Plus)) => {
accumulator.push_str(format!("{}", i).as_slice());
}
ast::LitInt(i, ast::SignedIntLit(_, ast::Minus)) |
ast::LitInt(i, ast::UnsuffixedIntLit(ast::Minus)) => {
accumulator.push_str(format!("-{}", i).as_slice());
}
ast::LitBool(b) => {
accumulator.push_str(format!("{}", b).as_slice());
}
ast::LitByte(..) |
ast::LitBinary(..) => {
cx.span_err(e.span, "cannot concatenate a binary literal");
}
}
}
_ => {
cx.span_err(e.span, "expected a literal");
}
}
}
base::MacExpr::new(cx.expr_str(
sp,
token::intern_and_get_ident(accumulator.as_slice())))
}