Pervasives.p: Use Builtin::show
Add exception expression
Bug fix: VM.unexport_*
Add Insn.MakeExceptionCtor
Parse ([]) & ([]=)
Add Builtin::string_get
Add String::C#([])
Add Builtin::string_length
prelude.sn: Add Stream
prelude.sn: Add Buffer
Pass all tests in test.sn