我正在尝试为自己正在使用的业余编程语言实现Reader
类。读取者的工作非常简单,即读取源文件并删除注释。
这是Reader
类的定义:
// reader.hh
// Contains Reader Class specifications
#ifndef PHI_SRC_FRONTEND_READER_HH
#define PHI_SRC_FRONTEND_READER_HH
#include "errhandler.hh"
class Reader
{
public:
Reader() = default;
auto val() const -> String const & { return val_; }
void read(String const &filename);
explicit operator bool() const { return success; }
auto operator!() const -> bool { return !success; }
friend auto operator==(Reader const &lhs, Reader const &rhs) -> bool
{
return lhs.val_ == rhs.val_;
}
friend auto operator!=(Reader const &lhs, Reader const &rhs) -> bool
{
return lhs.val_ != rhs.val_;
}
friend auto operator<<(std::ostream &stream, Reader const &read) -> std::ostream &
{
return stream << read.val_;
}
private:
String val_;
bool success;
};
#endif
以前,我为Reader
的{{1}}函数使用了一个非常简单的占位符。基本上,它使用istreambuf_iterator复制了文件中的所有内容
read
这很好,它通过了单元测试,我也手动检查了输出,也很好。
但这只是一个占位符,实际的void Reader::read(String const &filename)
{
val_.clear();
success = true; // success flag, true by default
auto file = std::ifstream{filename};
if(!file)
{
log_error(Error{Error::Type::ReadError, "Could not open file"});
success = false;
}
val_.assign(std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>());
// Read entire file into val_
}
需要删除注释。这使我得以实现:
Reader
但是,这很奇怪地导致单元测试失败。。我已经比较了// reader.cc
// Contains Reader Class Implementation
// Work In Progress, placeholders being used for now
#include <fstream>
#include <sstream>
#include "reader.hh"
void Reader::read(String const &filename)
{
val_.clear();
success = true; // success flag, true by default
auto inStringLiteral = false;
// Variable to determine if the reader is currently reading a string literal
// (enclosed in double quotes)
// In order to not mistake '//' inside literals as comments"
auto file = std::ifstream{filename};
if(!file)
{
log_error(Error{Error::Type::ReadError, "Cannot open file: " + filename});
success = false;
return;
}
for (unsigned char c; file >> c; )
{
// ASCII characters only use 7 bits, which is up to 127
// So value of an ascii char must be lesser than 128
if (c < 128)
{
if(c == '"')
{
inStringLiteral = !inStringLiteral; // flip the value of the boolean
}
if(!inStringLiteral && c == '/')
{
// If we're not inside a string literal enclosed in quotes, and find a backslash
// Peek at the next character to check if it is a backslash
// In case two consecutive backslashes are found, treat it as a comment and
// ignore everything until the end of line
if(file >> c)
{
if(c == '/')
{
// keep reading until a newline is found
while(file >> c && c != '\n')
{
}
}
else
{
c = '/';
file.unget();
}
}
else
{
c = '/';
}
}
val_ += c;
}
else
{
log_error(Error{Error::Type::ReadError, "Unrecognized character(s) found in file: " + filename});
success = false;
return;
}
}
}
函数的两个版本的输出,(显然)它们的输出完全相同。注意,我实际上没有检查字符串的相等性,但是它们确实 look 相同。我已经尝试找到很多错误的原因,但是失败了。...
这是我用于阅读器的单元测试(使用GoogleTest):
read
正如我之前提到的,它在第一个占位符版本中工作得很好,但是实际的#include <gtest/gtest.h>
#include "frontend/reader.hh"
TEST(ReaderTest, BaseTestCase)
{
auto TestReader = Reader{};
auto const ExpectedOutput = String{
R"delim(Int test = 0;
String test2 = "abcdefgh";
Float test3 = 0.9876;
)delim"};
TestReader.read("TestFiles/ReaderTest_BaseTestCase.phi");
ASSERT_FALSE(!TestReader);
ASSERT_EQ(TestReader.val(), ExpectedOutput);
// If Reader Base Test Case fails, no need to continue next tests
}
TEST(ReaderTest, Should_Fail_When_FileDoesNotExist)
{
auto TestReader = Reader{};
TestReader.read("Non_existent_test_file.txt");
EXPECT_TRUE(!TestReader);
}
函数似乎没有通过测试。...奇怪的是,示例文件没有通过甚至有任何评论,这是读者阅读的示例文件:
read
(是的,从字面上看是正确的。正如我之前提到的,读者正在阅读的语言不是C ++,而是我正在研究的一种自制语言,但这可能与这个问题无关。)
哦,如果您需要编译它,则需要实现和定义errhandler(errhandler.hh和errhandler.cc),我也将它们放在这里:
声明(errhandler.hh):
Int test = 0;
String test2 = "abcdefgh";
Float test3 = 0.9876;
定义(errhandler.cc):
// errhandler.hh
// Contains Phi Error Handling specifications
// Mostly complete, minor changes still might be made though
#ifndef PHI_SRC_FRONTEND_ERRHANDLER_HH
#define PHI_SRC_FRONTEND_ERRHANDLER_HH
#include <iostream>
#include "utils.hh"
class Error
{
public:
enum class Type : unsigned char
{
ReadError, LexError, ParseError, SemanticError, InterpretError
};
Error() = delete;
Error(Type type__, String const &val__) : type_(type__), val_(val__) {}
auto type() const -> Type { return type_; }
auto val() const -> String { return val_; }
friend auto operator<<(std::ostream &stream, Error const &error) -> std::ostream&
{
return stream << error.val();
}
private:
Type type_;
String val_;
};
class ErrorLog
{
public:
using iterator = Vector<Error>::iterator;
using const_iterator = Vector<Error>::const_iterator;
using reverse_iterator = Vector<Error>::reverse_iterator;
using const_reverse_iterator = Vector<Error>::const_reverse_iterator;
void push(Error const &error) { errors.push_back(error); }
void pop() { errors.pop_back(); }
auto size() const -> Size { return errors.size(); }
auto operator[](Size index) -> Error& { return errors[index]; }
auto operator[](Size index) const -> Error const& { return errors[index]; }
auto begin() -> iterator { return errors.begin(); }
auto end() -> iterator { return errors.end(); }
auto cbegin() const -> const_iterator { return errors.cbegin(); }
auto cend() const -> const_iterator { return errors.cend(); }
auto rbegin() -> reverse_iterator { return errors.rbegin(); }
auto rend() -> reverse_iterator { return errors.rend(); }
auto crbegin() -> const_reverse_iterator { return errors.crbegin(); }
auto crend() -> const_reverse_iterator { return errors.crend(); }
friend auto operator<<(std::ostream &stream, ErrorLog const &error_log) -> std::ostream&
{
for (Size i = 0; i < error_log.size(); i++)
stream << error_log[i];
return stream;
}
private:
Vector<Error> errors;
};
void log_error(Error const &error);
void show_errors(std::ostream& stream);
extern ErrorLog errlog;
// The global error log to be used by every part of the Phi system
// To be declared in main()
#endif
最后,您还需要包含实用程序的utils标头
// errhandler.cc
// Contains Phi Error Handling implementation
// Work In Progress, placeholders are temporarily being used
#include "errhandler.hh"
void log_error(Error const& error)
{
errlog.push(error);
}
void show_errors(std::ostream& stream)
{
stream << errlog;
}
这个问题确实使我在该项目上的进展停了下来。帮助我解决问题真的很有帮助
答案 0 :(得分:0)
因此,评论中的人确实为我提供了帮助,建议我使用>>而不是eof()和get()as eof() is unreliable来读取流中的字符。但是即使那样也解决不了问题。在我通过一些谷歌搜索自己弄清楚之前,我不得不使用std :: noskipws,以便使>>运算符不跳过空格,然后它起作用。感谢您的所有帮助,我非常感谢