We know prims are only symbols, so instead of checking for primitives in the top-level cond (which is expensive) we check for it as a sub-condition off of the (ref?) condition. This lets us avoid a call to memq unless we already are inspecting a symbol.
Having problems getting macros to work in a safe way with Cyc-seq. Since these functions were never a big win anyway, we are going to disable them for now.
Want to ensure cons can be used safely as part of a Cyc-seq. This cannot happen if the cons used the previous make_pair macro as that can only be called at the top of a function as part of a declaration.
This avoids ordering issues. But I think we still have trouble with other primtives. Is there ever a legitimate need to declare a c var for a prim??? I am not seeing it, especially with our changes now for Cyc-seq.
If the variable is not used we will get a warning from the C compiler. So let's not generate a let unless the var is actually used.
We may want to revisit this later for a related optimization, maybe via Cyc-seq.
This prevents situations where local variables are allocated within local scope blocks and then are assigned to pointers. This is necessary as those locals are not guaranteed to remain on the stack once the block ends, so the pointer can easily point to random memory, leading to GC corruption and/or undefined behavior.