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| - | This is a new design for auditing in E. It is an alternative to the unshadowable-names/synEnv system currently implemented in [[E-on-Java]], and the give-the-auditor-access-to-everything currently in [[E-on-CL]].
| + | Joe-E is a subset of the Java programming language designed to support programming according to object-capability discipline. |
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| - | ==Basic implementation==
| + | The language guarantees additional security properties by placing restrictions on Java code, but does not modify programs or change their meaning. This allows programmers' existing knowledge of Java to be applied and existing compilers, debuggers, and other tools to be used with Joe-E programs. |
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| - | [[Environment]]s holding an opt[[Guard]] along with each binding. For each noun, the scope alleges that the corresponding [[slot]] (not slot value!) was returned from that guard (except for object expressions; see below).
| + | == Links == |
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| - | As a consequence of this, environments must not be [[Selfless]], since it is not necessarily possible to go from some product of a guard to a value it coerces to the same result. They may be [[PassByConstruction]], however.
| + | * [http://joe-e.googlecode.com/ Joe-E Home Page] |
| - | | + | * [http://www.cs.berkeley.edu/~daw/joe-e/ Original Joe-E Home Page] |
| - | (Note that [[FinalPattern]]s and [[VarPattern]]s must get FinalSlot and VarSlot guards; e.g. <code>def x :int := 1</code> has a guard-in-environment of <code>FinalSlot[int]</code>.)
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| - | Environments gain the method fetchGuard/2, similar to fetchSlot/2.
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| - | [[Audition]]s have one relevant method, [[Audition#getGuard/1|getGuard/1]]. Given a noun (string), it returns the environment's optGuard for that binding. (XXX seems to be some optional/required confusion here. Does this return null, or does it return 'any'? --[[User:Kevin Reid|Kevin Reid]] 08:58, 19 February 2008 (CST)) If the noun is not one of the free variables of the audition's object expression, or if the audit has already terminated, then an exception is thrown. | + | |
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| - | An additional component on kernel [[ObjectExpr]]s: the "<code>as</code>" clause, syntactically preceding the "<code>implements</code>", behaves like it but with the additional effect of making its value be the guard for the binding of the object name (without coercing the object). That is, <code>def x as Y {}</code> audits x with Y, and also causes the binding to be <code>("x", makeFinalSlot(<x>), FinalSlot[Y])</code>.
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| - | All bindings in the [[safeScope]] expose their values in their guards; that is, they are <code>("foo", bar, FinalSlot[Same[bar]])</code>.
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| - | ==Implications for auditors==
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| - | ==Implications for guards==
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| - | ==Open questions==
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| - | If environments are PassByConstruction, then, if a passed guard coerces some slot to a different slot upon unserialization, should the binding have the coerced value (i.e. now coerced twice), or should the binding forget the guard?
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Joe-E is a subset of the Java programming language designed to support programming according to object-capability discipline.
The language guarantees additional security properties by placing restrictions on Java code, but does not modify programs or change their meaning. This allows programmers' existing knowledge of Java to be applied and existing compilers, debuggers, and other tools to be used with Joe-E programs.
