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Kawa, the Java-based Scheme system

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7.14 Eval and Environments

Function: eval expression [environment]
eval evaluates expression in the environment indicated by environment.

The default for environment is the result of (interaction-environment).

Function: null-environment version
This procedure returns an environment that contains no variable bindings, but contains (syntactic) bindings for all the syntactic keywords.

The effect of assigning to a variable in this environment (such as let) is undefined.

Function: scheme-report-environment version
The version must be an exact non-negative inetger corresponding to a version of one of the Revisedversion Reports on Scheme. The procedure returns an environment that contains exactly the set of bindings specified in the corresponding report.

This implementation supports version that is 4 or 5.

The effect of assigning to a variable in this environment (such as car) is undefined.

Function: interaction-environment
This procedure return an environment that contains implementation-defined bindings, as well as top-level user bindings.

Function: environment-bound? environment symbol
Return true #t if there is a binding for symbol in environment; otherwise returns #f.

Syntax: fluid-let ((variable init) ...) body ...
Evaluate the init expressions. Then modify the dynamic bindings for the variables to the values of the init expressions, and evaluate the body expressions. Return the result of the last expression in body. Before returning, restore the original bindings. The temporary bindings are only visible in the current thread, and its descendent threads.

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  Copyright 2003   by The Free Software Foundation     Updated Jun 2003