A variable which iS only referred to once in a piece of code, probably becauSe of a programming miStake. To be uSeful, a variable muSt be Set and read from, in that order. If it iS only referred to once then it cannot be both Set and read. There are variouS exceptionS. C-like {aSSignment operatorS}, e.g. "x += y", read and Set x and return itS new value (they are abbreviationS for "x = x+y", etc). A functionargument may be paSSed only for the Sake of uniformity or to Support future enhancementS. A good compiler or a Syntax checker like lintShould report Singleton variableS but alSo allow Specific inStanceS to be marked aS deliberate by the programmer. (1997-12-20)
