Free EcmaScript Interpreter.  
A JavaScript interpreter written in Java.
 
 
Language extensions
FESI implements few language extensions and try to follow the standard as much as possible. This is unlike most implementation of JavaScript, which are unfortunately very incompatibles between them. However to be useful at all EcmaScript must be extended, at least to link it to some host application. Because many applications have some common needs, FESI extensions can be build as libraries and loaded on demand, using the Java dynamic loading capability. A host program will usually list the required extensions as part of its initialization (see the FESI Java library). The extensions only add host objects and functions as prescribe the the EcmaScript standard, they do not change existing functions or extend the syntax.
 

Builtin extensions

The builtin extensions are capabilities always present on the interpreter. They include the following capabilities:

tryEval(string[,default])
    tryEval evaluates the parameter as eval, but returns an object with two properties: value and error. If the evaluation is successful, the value properties contains the result of the evaluation and the error property is null (which tests as false). If the evaluation results in an error, the the value property is either the value of the default parameter (if specified) or undefined, and the error property contains an object describing the error, which is guaranteed to test as true. The error object string representation is some description of the error. In the future more detailed error information may be available.

 
throwError([stringOrException])
    throwError throws and exception. The parameter is converted to a string, and added as an exception parameter if it is a Throwable.

Loadable extensions

The following extensions are all loaded by default by the interactive interpreter. However they may or may not be loaded by a user program using the interpreter as an embedded language, depending on the caller.


BasicIO, BasicIOw and BasicIOs

Provide basic document and window based IO to enable to share some scripts with  interpreter hosted in browsers.
 BasicIO and BasicIOw documentation

JavaAccess

 Allows to created Java objects and provide access to any public Java class and function from an EcmaScript program.
 JavaAccess documentation

FileIO

Provides text file IO and directory manipulation functions to EcmaScript programs.
 FileIO documentation


Database

Provides simple database access functions (via JDBC) to EcmaScript programs.
 Database Access documentation


RegExp

Provides regular expression base search and replace, based on the ORO package..
 Regular Expression documentation


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Last update: 12 January 1999