c-string-switch

Generate a switch statement on a string for C/C++

C# allows doing:

switch(a_string)
{
  case "a": // do something
  case "asdf": // something else
  case "bumblebee": // etc
  default: // yo
}

You can't do that in C or C++. Here's a python script that lets you do emulate it.

Run:

python c-string-switch.py

And type in the strings:

a
asdf
bumblebee

That spits out on stdout some C code (C++ compatible) that includes an enum and a function that parses a string and returns an enum value. The enum labels are the string, with a 'k' in front.

enum Values {
  kUnknown = 0,
  ka,
  kasdf,
  kbumblebee
}

This lets you write:

switch(convert(a_string))
{
  case ka: // do something
  case kasdf: // something else
  case kbumblebee: // etc
  default: // yo
}

Performance-wise the convert function does a single pass through the input string, which should make it notably faster than any hashing approach which at least needs to read twice (but I have no benchmarks to prove it).

Command-line arguments

The script reads from stdin if there's no argument, and from the file named in the first argument if there is one.

There's no command-line arguments to control the name of the enum, the function, or how to generate the enum labels.

Security

There's precisely no input verification. Don't use this script on untrusted input and then compile and run the output.