只需要生成枚举。为此目的编写一个生成器大约需要5分钟的工作。
生成器代码在java和python，超级容易移植到任何你喜欢的语言，包括c++。
而且非常容易扩展任何你想要的功能。
示例输入:
First = 5
Second
Third = 7
Fourth
Fifth=11
生成头文件:
#include <iosfwd>
enum class Hallo
{
First = 5,
Second = 6,
Third = 7,
Fourth = 8,
Fifth = 11
};
std::ostream & operator << (std::ostream &, const Hallo&);
生成的CPP文件
#include <ostream>
#include "Hallo.h"
std::ostream & operator << (std::ostream &out, const Hallo&value)
{
switch(value)
{
case Hallo::First:
out << "First";
break;
case Hallo::Second:
out << "Second";
break;
case Hallo::Third:
out << "Third";
break;
case Hallo::Fourth:
out << "Fourth";
break;
case Hallo::Fifth:
out << "Fifth";
break;
default:
out << "<unknown>";
}
return out;
}
生成器以非常简洁的形式作为移植和扩展的模板。这个示例代码确实试图避免覆盖任何文件，但使用它仍然要自担风险。
package cppgen;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class EnumGenerator
{
static void fail(String message)
{
System.err.println(message);
System.exit(1);
}
static void run(String[] args)
throws Exception
{
Pattern pattern = Pattern.compile("\\s*(\\w+)\\s*(?:=\\s*(\\d+))?\\s*", Pattern.UNICODE_CHARACTER_CLASS);
Charset charset = Charset.forName("UTF8");
String tab = " ";
if (args.length != 3)
{
fail("Required arguments: <enum name> <input file> <output dir>");
}
String enumName = args[0];
File inputFile = new File(args[1]);
if (inputFile.isFile() == false)
{
fail("Not a file: [" + inputFile.getCanonicalPath() + "]");
}
File outputDir = new File(args[2]);
if (outputDir.isDirectory() == false)
{
fail("Not a directory: [" + outputDir.getCanonicalPath() + "]");
}
File headerFile = new File(outputDir, enumName + ".h");
File codeFile = new File(outputDir, enumName + ".cpp");
for (File file : new File[] { headerFile, codeFile })
{
if (file.exists())
{
fail("Will not overwrite file [" + file.getCanonicalPath() + "]");
}
}
int nextValue = 0;
Map<String, Integer> fields = new LinkedHashMap<>();
try
(
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(inputFile), charset));
)
{
while (true)
{
String line = reader.readLine();
if (line == null)
{
break;
}
if (line.trim().length() == 0)
{
continue;
}
Matcher matcher = pattern.matcher(line);
if (matcher.matches() == false)
{
fail("Syntax error: [" + line + "]");
}
String fieldName = matcher.group(1);
if (fields.containsKey(fieldName))
{
fail("Double fiend name: " + fieldName);
}
String valueString = matcher.group(2);
if (valueString != null)
{
int value = Integer.parseInt(valueString);
if (value < nextValue)
{
fail("Not a monotonous progression from " + nextValue + " to " + value + " for enum field " + fieldName);
}
nextValue = value;
}
fields.put(fieldName, nextValue);
++nextValue;
}
}
try
(
PrintWriter headerWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(headerFile), charset));
PrintWriter codeWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(codeFile), charset));
)
{
headerWriter.println();
headerWriter.println("#include <iosfwd>");
headerWriter.println();
headerWriter.println("enum class " + enumName);
headerWriter.println('{');
boolean first = true;
for (Entry<String, Integer> entry : fields.entrySet())
{
if (first == false)
{
headerWriter.println(",");
}
headerWriter.print(tab + entry.getKey() + " = " + entry.getValue());
first = false;
}
if (first == false)
{
headerWriter.println();
}
headerWriter.println("};");
headerWriter.println();
headerWriter.println("std::ostream & operator << (std::ostream &, const " + enumName + "&);");
headerWriter.println();
codeWriter.println();
codeWriter.println("#include <ostream>");
codeWriter.println();
codeWriter.println("#include \"" + enumName + ".h\"");
codeWriter.println();
codeWriter.println("std::ostream & operator << (std::ostream &out, const " + enumName + "&value)");
codeWriter.println('{');
codeWriter.println(tab + "switch(value)");
codeWriter.println(tab + '{');
first = true;
for (Entry<String, Integer> entry : fields.entrySet())
{
codeWriter.println(tab + "case " + enumName + "::" + entry.getKey() + ':');
codeWriter.println(tab + tab + "out << \"" + entry.getKey() + "\";");
codeWriter.println(tab + tab + "break;");
first = false;
}
codeWriter.println(tab + "default:");
codeWriter.println(tab + tab + "out << \"<unknown>\";");
codeWriter.println(tab + '}');
codeWriter.println();
codeWriter.println(tab + "return out;");
codeWriter.println('}');
codeWriter.println();
}
}
public static void main(String[] args)
{
try
{
run(args);
}
catch(Exception exc)
{
exc.printStackTrace();
System.exit(1);
}
}
}
并将其移植到Python 3.5，因为它的不同可能会有所帮助
import re
import collections
import sys
import io
import os
def fail(*args):
print(*args)
exit(1)
pattern = re.compile(r'\s*(\w+)\s*(?:=\s*(\d+))?\s*')
tab = " "
if len(sys.argv) != 4:
n=0
for arg in sys.argv:
print("arg", n, ":", arg, " / ", sys.argv[n])
n += 1
fail("Required arguments: <enum name> <input file> <output dir>")
enumName = sys.argv[1]
inputFile = sys.argv[2]
if not os.path.isfile(inputFile):
fail("Not a file: [" + os.path.abspath(inputFile) + "]")
outputDir = sys.argv[3]
if not os.path.isdir(outputDir):
fail("Not a directory: [" + os.path.abspath(outputDir) + "]")
headerFile = os.path.join(outputDir, enumName + ".h")
codeFile = os.path.join(outputDir, enumName + ".cpp")
for file in [ headerFile, codeFile ]:
if os.path.exists(file):
fail("Will not overwrite file [" + os.path.abspath(file) + "]")
nextValue = 0
fields = collections.OrderedDict()
for line in open(inputFile, 'r'):
line = line.strip()
if len(line) == 0:
continue
match = pattern.match(line)
if match == None:
fail("Syntax error: [" + line + "]")
fieldName = match.group(1)
if fieldName in fields:
fail("Double field name: " + fieldName)
valueString = match.group(2)
if valueString != None:
value = int(valueString)
if value < nextValue:
fail("Not a monotonous progression from " + nextValue + " to " + value + " for enum field " + fieldName)
nextValue = value
fields[fieldName] = nextValue
nextValue += 1
headerWriter = open(headerFile, 'w')
codeWriter = open(codeFile, 'w')
try:
headerWriter.write("\n")
headerWriter.write("#include <iosfwd>\n")
headerWriter.write("\n")
headerWriter.write("enum class " + enumName + "\n")
headerWriter.write("{\n")
first = True
for fieldName, fieldValue in fields.items():
if not first:
headerWriter.write(",\n")
headerWriter.write(tab + fieldName + " = " + str(fieldValue))
first = False
if not first:
headerWriter.write("\n")
headerWriter.write("};\n")
headerWriter.write("\n")
headerWriter.write("std::ostream & operator << (std::ostream &, const " + enumName + "&);\n")
headerWriter.write("\n")
codeWriter.write("\n")
codeWriter.write("#include <ostream>\n")
codeWriter.write("\n")
codeWriter.write("#include \"" + enumName + ".h\"\n")
codeWriter.write("\n")
codeWriter.write("std::ostream & operator << (std::ostream &out, const " + enumName + "&value)\n")
codeWriter.write("{\n")
codeWriter.write(tab + "switch(value)\n")
codeWriter.write(tab + "{\n")
for fieldName in fields.keys():
codeWriter.write(tab + "case " + enumName + "::" + fieldName + ":\n")
codeWriter.write(tab + tab + "out << \"" + fieldName + "\";\n")
codeWriter.write(tab + tab + "break;\n")
codeWriter.write(tab + "default:\n")
codeWriter.write(tab + tab + "out << \"<unknown>\";\n")
codeWriter.write(tab + "}\n")
codeWriter.write("\n")
codeWriter.write(tab + "return out;\n")
codeWriter.write("}\n")
codeWriter.write("\n")
finally:
headerWriter.close()
codeWriter.close()
