The JEQL Language Specification

Scripts

script ::=	[ import-directive ] * [ statement ] *
import-directive ::=	import class-name ;
statement ::=	assignment-statement \| command-statement
assignment-statement ::=	assignment ;
assignment ::=	variable-name = expr
variable-name ::=	Identifier
command-statement ::=	command ;

The basic unit of execution in JEQL is the script. A script is a sequence of directives and statements which when executed cause data processing to take place.

Import Directives

Import directives allow declaring external functions and commands which are to be made available to the script. Imported functions and commands are loaded by the standard Java classloader, and thus must be available in the Java classpath.

Script Execution

Statements are executed sequentially in the order in which they appear in the script. The script terminates once the last statement has been executed. The script may be terminated prior this by one of:

During the execution of a function or command script termination is requested
An exception is thrown

Interaction with external environment

Scripts may take input from the command line or from external data sources. They may produce output on the standard output or to external data sources.

Errors

Scripts may encounter compilation or execution errors. Errors are reported via exceptions thrown. Exceptions are usually logged to the standard error output, although other JEQL containers may choose a different method of reporting.