mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Jon MeowandGeoff Romer
250ce4ab00
It was in my mind to add String in order to support libraries in `package`. `print` is added in order to have a String go to stdout. I've tried to do `print` in a way that won't be too hard to add other printable types, but it's probably also somewhat optional here -- that is, if desired, I could remove it. But it was a lot easier to doublecheck `\n` behavior with it, and I suspect it'll be helpful in other tests if it supports more value types. On the side, this also fixes dereferencing in Pattern/Expression Print() calls, which I was noticing printing pointers instead of values. This may be another argument for moving away from passing pointers, since this seems to be a difficult-to-catch error. Co-authored-by: Geoff Romer <gromer@google.com>
89 lines
2.1 KiB
C++
89 lines
2.1 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
|
|
// Exceptions. See /LICENSE for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
|
|
#include "common/string_helpers.h"
|
|
|
|
#include "common/check.h"
|
|
#include "llvm/ADT/StringExtras.h"
|
|
|
|
namespace Carbon {
|
|
|
|
// Carbon only takes uppercase hex input.
|
|
static auto FromHex(char c) -> std::optional<char> {
|
|
if (c >= '0' && c <= '9') {
|
|
return c - '0';
|
|
}
|
|
if (c >= 'A' && c <= 'F') {
|
|
return 10 + c - 'A';
|
|
}
|
|
return std::nullopt;
|
|
}
|
|
|
|
auto UnescapeStringLiteral(llvm::StringRef source)
|
|
-> std::optional<std::string> {
|
|
std::string ret;
|
|
ret.reserve(source.size());
|
|
size_t i = 0;
|
|
while (i < source.size()) {
|
|
char c = source[i];
|
|
if (c == '\\') {
|
|
++i;
|
|
if (i == source.size()) {
|
|
return std::nullopt;
|
|
}
|
|
switch (source[i]) {
|
|
case 'n':
|
|
ret.push_back('\n');
|
|
break;
|
|
case 'r':
|
|
ret.push_back('\r');
|
|
break;
|
|
case 't':
|
|
ret.push_back('\t');
|
|
break;
|
|
case '0':
|
|
if (i + 1 < source.size() && llvm::isDigit(source[i + 1])) {
|
|
// \0[0-9] is reserved.
|
|
return std::nullopt;
|
|
}
|
|
ret.push_back('\0');
|
|
break;
|
|
case '"':
|
|
ret.push_back('"');
|
|
break;
|
|
case '\'':
|
|
ret.push_back('\'');
|
|
break;
|
|
case '\\':
|
|
ret.push_back('\\');
|
|
break;
|
|
case 'x': {
|
|
i += 2;
|
|
if (i >= source.size()) {
|
|
return std::nullopt;
|
|
}
|
|
std::optional<char> c1 = FromHex(source[i - 1]);
|
|
std::optional<char> c2 = FromHex(source[i]);
|
|
if (c1 == std::nullopt || c2 == std::nullopt) {
|
|
return std::nullopt;
|
|
}
|
|
ret.push_back(16 * *c1 + *c2);
|
|
break;
|
|
}
|
|
case 'u':
|
|
FATAL() << "\\u is not yet supported in string literals";
|
|
default:
|
|
// Unsupported.
|
|
return std::nullopt;
|
|
}
|
|
} else {
|
|
ret.push_back(c);
|
|
}
|
|
++i;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
} // namespace Carbon
|