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New for 4th Edition
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We have added exception handling to the Limbo language, replacing sys->rescue etc.
This is intended to make it more straightforward to write fault-tolerant subsystems.
The semantics broadly follow that used by the programming language CLU. There are many advantages:
it is structured and fits into the language rather than being bolted on;
the programmer, compilers and JIT can see the scope of exception handlers,
allowing the system (for instance) to nil out values in the block on an exception, and get
register allocation right;
and the implementation is better. The source changes to Limbo applications are relatively small,
and the result is tidier.
Status:Implemented
We have also added fixed-point arithmetic type and operators to Limbo.
The intention is to simplify the
implementation of fixed-point algorithms especially when interacting with
devices that provide fixed-point values or when working on a platform without
floating-point support.
The underlying model is broadly that developed for Ada-95's fixed-point
(with one or two artifacts left over from Ada-83 eliminated).
Status:Implemented
4 February 2003
More details and examples will appear here shortly.
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