Question

I am trying to write a function to transform a string literal in Delphi/pascal to the C equivalent. A string literal in Delphi matches the regex ("#"([0-9]{1,5}|"$"[0-9a-fA-F]{1,6})|"'"([^']|'')*"'")+ so that the string

"This is a test with a tab\ta breakline\nand apostrophe '"

will be written in Pascal as

'This is a test with a tab'#9'a breakline'#$A'and apostrophe '''

I managed to strip the apostrophes, but I am having trouble managing the special characters.

Answer 1

Simply use replaceApp() function that can be found at: http://www.cppreference.com/wiki/string/basic_string/replace

Then code can look as:

string s1 = "This is a test with a tab\\ta breakline\\nand apostrophe '";
string s2 = s1;
s2 = replaceAll(s2, "'", "''");
s2 = replaceAll(s2, "\\t", "'$7'");
s2 = replaceAll(s2, "\\n", "'$10'");
cout << "'" << s2 << "'";

Of course changes ‘\t’ -> ‘$7’ can be saved in some structure that you can use in loop instead of replacing each item in separate lines.

Edit:

Second solution (example taken from comment) with using map:

typedef map <string, string> MapType;
string s3 = "'This is a test with a tab'#9'a breakline'#$A'and apostrophe '''";
string s5 = s3;
MapType replace_map;
replace_map["'#9'"] = "\\t";
replace_map["'#$A'"] = "\\n";
replace_map["''"] = "'";
MapType::const_iterator end = replace_map.end();
for (MapType::const_iterator it = replace_map.begin(); it != end; ++it)
    s5 = replaceAll(s5, it->first, it->second);
cout << "s5 = '" << s5 << "'" << endl;