Add 'with' expression.
InitSlots expression.
Fixed a bug of `with' expression.
Rewrite libraries using 'with' expression.
Minor fix
Fixed a GC-related bug of bytecode.
Remove unnecessary information of vm_instructions.
Partial continuation.
minor fix of reset_push/pop.
Changed implementation of exception stack not to use machine stack.
Fixed a bug: 'return' from 'try-catch' block.
Working snapshot (Implementation of partial continuation)
Fixed GC for partial continuations.
Add lib/IO.ab and lib/IO/StringStream.ab.
working on REPL.
Working snapshot.
Overwritable operations.
Add InputStringStream.ab
Add StringTrait.to_i and to_f.
Add Numeric.Bit module.