# ctod
**GitHub:** https://github.com/dkorpel/ctod
**Dub:** https://code.dlang.org/packages/ctod
---
In the summer of 2020, before ImportC, I wrote a tool to help me
with my D translations of C libraries:
[glfw-d](https://code.dlang.org/packages/glfw-d) and
[libsoundio-d](https://code.dlang.org/packages/libsoundio-d). I
wanted to publish it at some point but kind of forgot about it,
until [Steven Schveighoffer asked about
it](https://github.com/dkorpel/glfw-d/discussions/18) last week
for his [D translation of
raylib](https://github.com/schveiguy/draylib). That made me
inspired to work on it again, and I finally fixed the Windows
build, so I want to share it now.
It uses
[tree-sitter-c](https://github.com/tree-sitter/tree-sitter-c) to
parse .c or .h files including preprocessor directives, and then
replaces C syntax patterns with roughly equivalent D patterns
wherever it needs and can. Because tree-sitter is very good at
error-recovery, it will always output a best-effort translated .d
file, no matter the content of the .c file.
Example input file main.c:
```C
#include <stdio.h>
#define TAU 6.283185307179586476925
int main(void) {
char buf[32];
sprintf(buf, "tau = %f\n", TAU);
Wait, this line is not C syntax 🤔
return 0;
}
```
Output main.d:
```D
module main;
@nogc nothrow:
extern(C): __gshared:
public import core.stdc.stdio;
enum TAU = 6.283185307179586476925;
int main() {
char[32] buf;
sprintf(buf.ptr, "tau = %f\n", TAU);
Wait, this_ line is_; not C syntax 🤔
return 0;
}
```
The output is supposed to be a good starting point for manual
translation: tedious syntax changes are done for you, but you're
left with the task of translating (non-trivial) macros, fixing
errors because of D's stricter type system, and other misc things
ctod doesn't translate properly yet (see also [issues on
GitHub](https://github.com/dkorpel/ctod/issues) 🙂).
With the rise of ImportC the use cases for this tool decrease,
but in case you still find yourself translating C to D, I hope
this is of use to you!
