import std.stdio;
import std.file;
import fe;
import core.stdc.stdlib;

int main(string[] args)
{
    if (args.length != 2)
    {
        writeln("Usage: fe-interp <source.fe>");
        return 1;
    }

    int size = 1024 * 1024;
    void* data = malloc(size);

    fe_Context* ctx = fe_open(data, size);
    const(char)[] source = cast(char[]) std.file.read(args[1]);

    struct UserContext
    {
        const(char)[] remain;
    }

    static char readInBuf(fe_Context *ctx, void* udata)
    {
        UserContext* uc = cast(UserContext*)udata;
        if (uc.remain.length == 0)
            return '\0';
        else
        {
            char c = uc.remain[0];
            uc.remain = uc.remain[1..$];
            return c;
        }
    }

    int gc = fe_savegc(ctx);
    UserContext uc;
    uc.remain = source;
    while(true)
    {
        fe_Object *obj = fe_read(ctx, &readInBuf, &uc);

        // break if there's nothing left to read
        if (!obj) break;

        // evaluate read object
        fe_eval(ctx, obj);
    }
    // restore GC stack which would now contain 
    // both the read object and result from evaluation
    fe_restoregc(ctx, gc);

    fe_close(ctx);
    return 0;
}