lazyhotreload.d

/*
lazy hotload: hot reload a single function file, depends on opend imports

kinda dumb, dont expect templates, changing headers or anything to work

pass relivtivepath filename without the `.d`
*/

import core.stdc.stdlib;
import core.sys.posix.dlfcn;
//import std;
enum PATH=__FILE_FULL_PATH__[0..$-__FILE__.length];
template hotload(string file){
	mixin("import "~file~";");
	enum code=import(file~".d");
	enum name=findname(code);
	pragma(msg,"hotloading file "~file~" as function "~name);
	alias F=mixin(file~"."~name);
	pragma(msg,"this is parsing as "~typeof(F).stringof);
	enum mangle=F.mangleof;
	enum filepath=PATH~file~".so";
	pragma(msg,"mangle:"~mangle);
	bool recompile=true;
	void* handle;
	typeof(&F) call;
	auto hotload(T...)(T args){
		if(recompile){
			compile(file);
		}
		handle=dlopen(&filepath[0],RTLD_LAZY);
		assert(handle!=null,"put here: dlerror.to!string");
		call=cast(typeof(&F)) dlsym(handle,mangle);
		auto out_=call(args);
		dlclose(handle);
		return out_;
	}
}
string findname(string code){
	int i/*,j*/,k;
	while(code[++i]!='('){}
	k=i;
	while(code[--i]!=' '){}
	i++;
	return code[i..k];
}
void compile(string file){
	enum compiler="opend -shared -of=";
	system(&(compiler~file~".so "~file~".d\0")[0]);
}
//void main(){
//	import std;
//	while(true){
//		hotload!"foo"(3).writeln;
//		readln;
//	}
//}