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PLCOPEN-N6: Define an acceptable name length

Identifiers shorter than a configured minimum or longer than a configured maximum should be renamed.

Why is it bad?​

Two-letter names like Go or Tm are impossible to grep for and hide their meaning. At the other extreme, 30+ character identifiers hurt readability, push real logic off the screen and tend to encode information that belongs in a comment or a grouping type. A sensible band — three characters up to twenty-five — strikes a useful balance.

Configuration​

This lint is opt-in. Set one or both bounds in iec_checker.json:

{
  "detectors": { "enabled": ["PLCOPEN-N6"] },
  "naming_conventions": {
    "min_length": 3,
    "max_length": 25
  }
}

Leave a field at 0 (or omit it) to disable that side of the check. The rule is applied to every variable declaration, function name, function block name, program name, class name, interface name and user-defined type name.

Example​

FUNCTION Go : BOOL                               (* PLCOPEN-N6 — too short *)
END_FUNCTION

FUNCTION ReadAndScaleTheTemperatureInput : REAL  (* PLCOPEN-N6 — too long *)
END_FUNCTION

FUNCTION StartFeeding : BOOL                     (* ok *)
END_FUNCTION

Resources​

  1. PLCOpen Software Construction Guidelines