Python script for evaluating single line C/C++ code

eval_c.py

import sys,os
import subprocess

types = { 'int' : '%d', 
          'long' : '%ld', 
          'long long' : '%lld', 
          'float' : '%.32f', 
          'double' : '%.56f', 
          'unsigned' : '%u', 
          'unsigned long' : '%lu', 
          'unsigned long long' : '%llu', 
          'str' : '%s' }

compilers = { 'gcc' : 'c', 'g++' : 'cpp' }

cpp_template = """
#include <iostream>
#include <limits>
#include <cmath>
#include <iomanip>

int main()
{
	std::cout << std::setprecision(50) << (%s) << std::endl;

	return 0;
}

"""

c_template = """
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <limits.h>

int main()
{
	printf("%s\\n",%s);

	return 0;
}

"""

if 2 < len(sys.argv) < 5:
	compiler = sys.argv[1]

	out_type = None
	if len(sys.argv) == 4:
		out_type = sys.argv[2]
		code_line = sys.argv[3]
	else:
		code_line = sys.argv[2]

	if compiler not in compilers:
		print('compiler %s unsupported' % compiler)
		sys.exit(-1)

	lang = compilers[compiler]	

	if lang != 'c':
		out_type = None

	if lang == 'c' and out_type is None:
		print('c compilation requires return type')
		sys.exit(-1)

	if lang == 'c' and out_type not in types:
		print('type %s unsupported for c compilation' % out_type)
		sys.exit(-1)

	if code_line[-1] == ';':
		code_line = code_line[:-1]

	filename = "tmp." + lang
	template = c_template if lang == "c" else cpp_template

	with open(filename,"w") as fout:
			args = (code_line) if out_type is None else (types[out_type],code_line)
			fout.write(template % args)
	os.system("%s -o tmp %s" % (compiler,filename))

	process = subprocess.Popen(['./tmp'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
	out,err = process.communicate()

	if err.decode() == '':
		print(out.decode().rstrip())
	else:
		print('ERROR: ' + err.decode().rstrip())
	
else:
	print("   usage %s <compiler> [<return type>] <code>" % sys.argv[0])