ILOG OPL Development Studio Language Reference Manual

Automatic conversion to a numberWhen a function or a method which expects a number as one of its arguments is passed anonnumeric value, it tries to convert this value to a number using the following rules:♦A string is parsed as a number literal. If the string does not represent a valid number literal,the conversion yields NaN.♦The Boolean true yields the number 1.♦The Boolean false yields the number 0.♦The null value yields the number 0.♦A date yields the corresponding number of milliseconds since 00:00:00 UTC,January 1, 1970.For example, if the Math.sqrt function is passed a string, this string is converted to thenumber it represents:Math.sqrt("25") 5Similarly, operators which take numeric operands attempt to convert any nonnumeric operandsto a number:"3" * "4" 12For operators that can take both strings (concatenation) and numbers (addition), such as +,the conversion to a string takes precedence over the conversion to a number (See Automaticconversion to a string.). In other words, if at least one of the operands is a string, the otheroperand is converted to a string; if none of the operands is a string, the operands are bothconverted to numbers. For example:"3" + true "3true"3 + true 4For comparison operators, such as == and >=, the conversion to a number takes precedenceover the conversion to a string. In other words, if at least one of the operands is a number, theother operand is converted to a number. If both operands are strings, the comparison is madeon strings. For example:"10" > "2" false"10" > 2 true214I L O G O P L D E V E L O P M E N T S T U D I O L A N G U A G ER E F E R E N C E M A N U A L