Convention: Variable Name Checks

User Description

Coding style is a set of rules or guidelines applied when writing source code. Following a specified coding style helps:

• To read and understand the source code

• To avoid and find programming issues

• To maintain the source code

Based on the Programming Guidelines (Naming Conventions, Prefixes) for source code, variable name convention queries are available to verify the suggested variable name per data type and variable scope.

Convention Verification Rule

For convention verification, the variable name is combined with its linked data type and the scope where the variable is defined in.

Scopes:

• Local variable scope: No special scope prefix (VAR ... END_VAR)

• Input variable scope: i_ as prefix (VAR_INPUT ... END_VAR)

• Output variable scope: q_ as prefix (VAR_OUTPUT ... END_VAR)

• In-/Output variable scope: iq_ as prefix (VAR_IN_OUT_ ... END_VAR)

• Global variable scope: G_ as prefix

• Global constants scope: Gc_ as prefix

• etc.

Variable name prefixes based on data type:

• INT: i as prefix

• DINT: di as prefix

• UDINT: udi as prefix

• REAL: r as prefix

• LREAL: lr as prefix

• Function block: fb as prefix

• POINTER TO: p as prefix

• etc.

Example

VAR
    iMyVariable1: INT;
    uiMyVariable1: UINT;
    rMyVariable1: REAL;
    piMyVariable7: POINTER TO INT;
END_VAR
VAR_INPUT
    i_iMyVariable2: INT;
    i_uiMyVariable2: UINT;
    i_rMyVariable2: REAL;
END_VAR
VAR_IN_OUT
    iq_iMyVariable3: INT;
    iq_uiMyVariable3: UINT;
    iq_rMyVariable3: REAL;
END_VAR
VAR_OUTPUT
    iq_iMyVariable2: INT;
    iq_uiMyVariable2: UINT;
    iq_rMyVariable2: REAL;
END_VAR