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  1. #include <string>
  2. #include <iostream>
  3. #include <regex>
  4.  
  5. void replaceSystemEnviromentTokens(std::string& var)
  6. {
  7. 	static std::string tokenOpening = "\\[\\[";
  8. 	static std::string tokenClosure = "\\]\\]";
  9. 	auto getEnvVal = [](const std::string& var) {
  10. 		char* val = getenv(var.c_str());
  11. 		return std::string(val ? val : "");
  12. 	};
  13.  
  14. 	std::regex re(tokenOpening + "(\\S+)" + tokenClosure);
  15. 	std::sregex_iterator it(var.begin(),var.end(),re);
  16. 	std::sregex_iterator end;
  17. 	while (it != end) {
  18. 		auto& m = *it;
  19. 		auto value = getEnvVal(m.str(1));
  20. 		if (!value.empty()) {
  21. 			std::regex re_replace(tokenOpening + m.str(1) + tokenClosure);
  22. 			var = regex_replace(var, re_replace, value);
  23. 			it = std::sregex_iterator(var.begin(), var.end(), re);
  24. 		}
  25. 		else {
  26. 			++it;
  27. 		}
  28. 	}
  29. }
  30.  
  31. int main(int argc, char** argv) 
  32. {
  33. 	putenv(R"(VULKAN_SDK=C:\VulkanSDK\1.2.148.1)");
  34. 	std::string test = "this should be converted: [[VULKAN_SDK]] this should not be converted: VULKAN_SDK]] this: [[VULKAN_SDK]]";
  35. 	replaceSystemEnviromentTokens(test);
  36. 	std::cout << test << std::endl;
  37.  
  38. 	test = "nothing to convert here";
  39. 	replaceSystemEnviromentTokens(test);
  40. 	std::cout << test << std::endl;
  41.  
  42. 	test = "something to convert here: [[PATH]]";
  43. 	replaceSystemEnviromentTokens(test);
  44. 	std::cout << test << std::endl;
  45.  
  46. 	test = "something [[NOT_IN_ENV]] to convert [[PATH]]. A non existing one [[MISSING]]... Stop there! Another good conversion [[PATH]].";
  47. 	replaceSystemEnviromentTokens(test);
  48. 	std::cout << test << std::endl;
  49. }
  50.  
Success #stdin #stdout 0s 4776KB
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Standard input is empty
stdout
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this should be converted: C:\VulkanSDK\1.2.148.1 this should not be converted: VULKAN_SDK]] this: C:\VulkanSDK\1.2.148.1
nothing to convert here
something to convert here: /usr/local/bin:/usr/bin:/bin
something [[NOT_IN_ENV]] to convert /usr/local/bin:/usr/bin:/bin. A non existing one [[MISSING]]... Stop there! Another good conversion /usr/local/bin:/usr/bin:/bin.
https://ideone.com/Hcb4BM
WORKING replaceSystemEnviromentTokens with regex
language:
C++14 (clang 8.0)
created:
4 years ago
visibility:
public

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