How to name variables

Question

• What rules do you use to name your variables?
• Where are single letter vars allowed?
• How much info do you put in the name?
• How about for example code?
• What are your preferred meaningless variable names? (after foo & bar)
• Why are they spelled "foo" and "bar" rather than FUBAR

Answer 1

function startEditing(){    if (user.canEdit(currentDocument)){       editorControl.setEditMode(true);       setButtonDown(btnStartEditing);    }  } 

Should read like a narrative work.

Answer 2

One rule I always follow is this: if a variable encodes a value that is in some particular units, then those units have to be part of the variable name. Example:

int postalCodeDistanceMiles; decimal reactorCoreTemperatureKelvin; decimal altitudeMsl; int userExperienceWongBakerPainScale 

I will NOT be responsible for crashing any Mars landers (or the equivalent failure in my boring CRUD business applications).