Changes between Version 4 and Version 5 of ImmutableParametersCowan


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Timestamp:
08/25/10 18:36:43 (7 years ago)
Author:
cowan
Comment:

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  • ImmutableParametersCowan

    v4 v5  
    11= Parameters = 
     2 
     3''I have replaced this proposal with ParametersCowan, which returns to SRFI 39 semantics.  The trouble with immutable parameters is that the the immutable value may be a mutable object like a cons, a vector, or a box, which reinstates the question "Is it shared?"'' 
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    35This proposal defines ''parameter objects'', the procedure `make-parameter` to create parameter objects and the `parameterize `special form to dynamically bind parameter objects. In the dynamic environment, each parameter object is bound to a value, which may be any Scheme object. When a procedure is invoked, the called procedure inherits the dynamic environment from the caller. The `parameterize` special form allows the binding of a parameter object to be changed for the dynamic extent of its body.