The CI contains a set of features that provides the key functions of a programming language:
Command files and user-defined commands—A mechanism for executing multiple CI commands in a prescribed sequence, similar to a procedure.
Variables—User-defined and predefined variables that can be accessed by the CI and application programs within the same session.
Expression evaluator—A command processing phase that resolves all arithmetic, string, and boolean expressions.
Language constructs—Command structures that simulate the branching, looping, input, and output structures needed for programmatic control.
CI intrinsics—An interface mechanism providing programmatic access to the CI from applications programs.
The programming capability of the CI can be used to simplify tasks. Complicated routines requiring multiple commands can be made transparent to users through the use of command files and user-defined commands (UDCs).
Some programming tasks can be coded more simply and efficiently with CI commands than with a standard application language. Routines can be written with CI commands and accessed from application programs through the intrinsic facility. Variables can be used by both CI routines and application programs to pass information between routines.
