Calling Rust from other languages

My lightning talk at PolyConf 2015.

Transcript

1. Zbigniew Siciarz @zsiciarz siciarz.net
2. Zbigniew Siciarz @zsiciarz siciarz.net (mostly) Python developer http://rustwarsaw.org/ http://zsiciarz.github.io/24daysofrust/
3. Zbigniew Siciarz @zsiciarz siciarz.net
4. Zbigniew Siciarz @zsiciarz siciarz.net
5. fn rust_substrings(value: &str, substr: &str) -> i32 { let mut count = 0; let substr_len = substr.len(); let upper_bound = value.len() - substr_len + 1; for c in 0..upper_bound { let possible_match = &value[c..c+substr_len]; if possible_match == substr { count += 1; } } count } Zbigniew Siciarz @zsiciarz siciarz.net
6. Zbigniew Siciarz @zsiciarz siciarz.net
7. #[no_mangle] pub extern "C" fn count_substrings( value: *const c_char, substr: *const c_char) -> i32 { let c_value = unsafe { CStr::from_ptr(value).to_bytes() }; let c_substr = unsafe { CStr::from_ptr(substr).to_bytes() }; match str::from_utf8(c_value) { Ok(value) => match str::from_utf8(c_substr) { Ok(substr) => rust_substrings(value, substr), Err(_) => -1, }, Err(_) => -1, } } Zbigniew Siciarz @zsiciarz siciarz.net
8. #include <stdint.h> #include <stdio.h> int32_t count_substrings(const char* value, const char* substr); int main() { printf("%d\n", count_substrings("banana", "na")); return 0; }s Zbigniew Siciarz @zsiciarz siciarz.net
9. import ctypes library_name = "../target/debug/libstringtools.so" stringtools = ctypes.CDLL(library_name) print(stringtools.count_substrings(b"banana", b"na")) Zbigniew Siciarz @zsiciarz siciarz.net
10. require 'ffi' module StringTools extend FFI::Library ffi_lib "../target/debug/libstringtools.so" attach_function :count_substrings, [:string, :string], :int end puts StringTools.count_substrings("banana", "na") Zbigniew Siciarz @zsiciarz siciarz.net
11. using System; using System.Runtime.InteropServices; public class StringTools { [DllImport("../target/debug/libstringtools.so")] public static extern Int32 count_substrings(string value, string substr); static public void Main() { Console.WriteLine(count_substrings("banana", "na")); } } Zbigniew Siciarz @zsiciarz siciarz.net
12. {-# LANGUAGE ForeignFunctionInterface #-} import Foreign.C.String (CString, newCString) foreign import ccall "count_substrings" count_substrings :: CString -> CString -> IO Int main :: IO () main = do value <- newCString "banana" substr <- newCString "na" count_substrings value substr >>= print Zbigniew Siciarz @zsiciarz siciarz.net
13. package main // #cgo LDFLAGS: -L../target/debug -lstringtools // int count_substrings(const char* value, const char* substr); import "C" import "fmt" func main() { value := C.CString("banana") substr := C.CString("na") fmt.Println(C.count_substrings(value, substr)) } Zbigniew Siciarz @zsiciarz siciarz.net
14. // sorry, code too long :( Zbigniew Siciarz @zsiciarz siciarz.net
15. Zbigniew Siciarz @zsiciarz siciarz.net http://jakegoulding.com/rust-ffi-omnibus/ https://github.com/zsiciarz/rust-ffi-stringtools https://github.com/alexcrichton/rust-ffi-examples https://doc.rust-lang.org/book/ffi.html