Differences Between OpenDream and BYOND

This is a work-in-progress guide describing the major differences between OpenDream and BYOND.

Breaking Changes

Various things cannot or will not be reconciled between OpenDream and BYOND.

Note that all unsupported procs should throw a compile-time warning if you try to use them in your DM code.

Hub Support

Since OpenDream does not have an equivalent to the BYOND hub, no procs or vars related to the hub will be functional, such as GetMedal().

BYOND Membership

Since we are not affiliated with BYOND, all users are treated as if they are not members. Procs like IsByondMember() will always return false.

External DLLs

All DLLs made for BYOND games are compiled targeting 32-bit. OpenDream targets 64-bit and DLLs will need to be recompiled.

Text Encoding

BYOND uses UTF-8, while C# uses UTF-16. As a result, length() and other text procs may return a different value for some strings.

Enhancements

The point of OpenDream is not just to provide an open-source implementation of Dream Maker, but to improve upon it. These enhancements are currently a very low priority compared to improving BYOND compatibility.

Proc Static Typing (Unmerged Proof-of-Concept)

Procs can now support a limited form of static typing. More details here.