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Arithmetic, Logical and Comparison Operators

Here is a list of the available operators in a SIL™ program and detailed usage information.

Arithmetic operators

In version 2.5 (and 3.0 yet again) we have reworked the way operators handle different types and conversions by putting an emphasis on the left-hand side (LHS) value of the operation. Consequently, only the right-hand side (RHS) operand will be converted (if necessary) to a type that is valid for the current operation with the LHS type.

For each operator and LHS type, we define two lists: valid types and convertible types. The list of convertible types is based on Type conversion. This creates three cases:

1. If the RHS type is one of the valid types, then the operation will proceed as it is and the result calculated according to the table below.
2. If the RHS type is one of the convertible types, then it will attempt to convert it to one of the valid types (in the order the valid types are presented in the table below) until the conversion succeeds and then proceeds according to case 1.
3. If the RHS type is neither valid nor convertible, the program will end in error.

string s = "a";
s = s + "b";
// is equivalent with
s += "b"; 

--i; 
i--;
++i;
i++;

Comparison operators

Logical operators

Ternary operators

<condition> ? <ifTrueValue> : <ifFalseValue>

The Indexing Operator

The basic use of the indexing operator (introduced in version 2.5) is to allow you to easily access the contents of a list.

string [] arr = {"a", "b", "c"};
string contents = arr[0] + arr[1] + arr[2] + arr[3]; // as user friendly as arrayGetElement, if index is out of bounds, will return an empty value.
arr[3] = "d";

Moreover, it allows you to create key-value lists (maps) and retrieve values from them by using a string inside the operator (instead of a number).

number [] map;
map["one"] = 1;
map["two"] = 2;
print(map["one"]);
// note that when used in a for-loop, map only has 2 elements: 1 and 2. The keys will be hidden.
print(map); // will print 1|2

When accessing a map as a list, the contents are retrieved in the order they were added. You can still use the operator with an integer value even on maps.

date [] days;
days["yesterday"] = currentDate() - "1d";  // added as first element
days["today"] = currentDate();		   // added as second element
days["tomorrow"] = currentDate() + "1d";   // added as third element
if(days["today"] == days[1]){
	print("Today is the second element in the array"); // yes, this will be printed
}

The indexing operator can also be used with certain simple types (not arrays) and a specific value to provide additional functionality.

See also

• Syntax & Types
• Variable resolution
• Statements