Interpret - Executing or explaining

z/OS Context

Enhanced Definition

In the z/OS environment, "interpret" primarily refers to the process where a program or system component directly reads, analyzes, and performs the actions specified by a set of instructions or commands without requiring a prior compilation step into machine code. It also encompasses the analysis of instructions or data to *explain* their meaning, purpose, or potential issues, such as during validation or debugging. "Executing" is the broader act of carrying out these instructions, whether they are interpreted or compiled.

Key Characteristics

- Dynamic Execution: Interpreted code, such as REXX EXECs or JCL, is processed and executed line-by-line or statement-by-statement at runtime, allowing for dynamic changes and immediate execution.
- No Prior Compilation: Unlike compiled languages (e.g., COBOL, PL/I), interpreted languages do not require a separate compilation phase to produce an executable load module.
- Runtime Error Detection: Errors in interpreted code are typically detected during execution, whereas compilation catches many errors before runtime.
- Pre-execution Validation: System components like JES (Job Entry Subsystem) interpret JCL for syntax and semantic errors *before* actual job step execution, providing *explanations* of potential problems.
- Debugging Capabilities: Interpreted environments often provide robust debugging tools (e.g., REXX TRACE) that allow step-by-step execution, variable inspection, and flow *explanation*.
- Resource Overhead: Interpretation generally incurs more CPU overhead per instruction compared to compiled code due to the real-time parsing and processing overhead.