SPIN Modula-3
We've made a bunch of changes to Modula-3. We also have a bunch
of recommendations on safe programming in our version of M3.
Style guide
Certain guidelines should be followed when
programming using objects.
Language changes
Here are the changes we have made from standard Modula-3, including
motivation for the change, new syntax and some examples. A
paper
describes most of these changes in more detail.
- VIEW
- Typesafe casting
- EPHEMERAL procedures
- Procedures which guarantee they won't screw up the system
even if they are terminated at an arbitrary point.
- FUNCTIONAL procedures
- Procedures which don't modify any global state.
- PROCANY type
- A supertype for all PROCEDURE types.
- RTCode interface
- An way to talk about Modula-3 modules and interfaces at runtime.
- EXTERNAL is UNSAFE
- Any interface containing <*EXTERNAL*> declarations must be
UNSAFE.
- IMPLICIT exceptions
- Exceptions that every procedure may raise, and that
do not need to be declared.
- ALIGNED FOR
- You can boost the alignment of types that need it.
- Object methods
- Calling and naming object methods explicitly is restricted.
- CVAR
- Calling C functions with call-by-reference.
Compiler options
We have added the following compiler options:
- -NoLoopholeWarnings
- Do not give warnings for
LOOPHOLE. Our compiler issues
a warning for every loophole.
- -SpinRelax
- Turn off SPIN restrictions, so that standard code can be compiled.
For example, turn off the requirement that
EXTERNAL be
UNSAFE.