Introduction¶

Data is often presented as delimiter separated values (e.g., CSV, TSV, …), which makes parsing of these formats a common task.

Here we introduce a lightweight and straightforward method for parsing delimiter separated files where the user only needs to specify a delimiter (and optionally a line ending delimiter) and a structure to receive the parsed data. This structure can be of any basic type, a string or an array.

Motivation¶

Suppose we want to parse a string containing five integers and store the result in an array. A straightforward way of doing this would be:

char const line[] = "1, 2, 3, 4, 5";

int a[5];
char* endptr = const_cast<char*>(line);
for (size_t i = 0; i < 5; i++) {
  a[i] = strtol(endptr, &endptr, 10);
  (*endptr) += 2;
}

If however, we decide that the type of the values should be float instead of int, we need to change two lines:

float a[5];                        // This one.
char* endptr = const_cast<char*>(line);
for (size_t i = 0; i < 5; i++) {
  a[i] = strtod(endptr, &endptr);  // And this one.
  (*endptr) += 2;
}

If we need to alternate between the types float and int, the structure of the code changes completely:

float a, c, e;
int b, d;
char* endptr = const_cast<char*>(line);
a = strtod(endptr, &endptr);
(*endptr) += 2;
b = strtol(endptr, &endptr, 10);
(*endptr) += 2;
c = strtod(endptr, &endptr);
(*endptr) += 2;
d = strtol(endptr, &endptr, 10);
(*endptr) += 2;
e = strtod(endptr, &endptr);

This library aims to provide a more uniform method to solve these problems. When we look at the example where we want to extract five integers from a string, the following piece of code is needed:

char const line[] = "1, 2, 3, 4, 5";
TextParser parser(", ");

int a[5];
parser.parseLine("1, 2, 3, 4, 5", a);

If again, we decide that the type of the values should be float, we now only have to change one line of code:

float a[5];  // This one.
parser.parseLine("1, 2, 3, 4, 5", a);

Similarly, more complex arrangements like the alternating types are handled as follows:

float a, c, e;
int b, d;
parser.parseLine("1, 2, 3, 4, 5", a, b, c, d, e);

Introduction¶

Motivation¶

Further Reading¶