PTOLEMY II - CiteSeerX

3.4 Composite Data Types
3.4.1 Arrays
Expressions
Arrays are specified with curly brackets, e.g., “{1, 2, 3}” is an array of int, while “{"x",
"y", "z"}” is an array of string. The types are denoted “{int}” and “{string}” respectively. An
array is an ordered list of tokens of any type, with the only constraint being that the elements all have
the same type. If an array is given with mixed types, the expression evaluator will attempt to losslessly
convert the elements to a common type. Thus, for example,
has value
{1, 2.3}
{1.0, 2.3}
Its type is {double}. The elements of the array can be given by expressions, as in the example
“{2*pi, 3*pi}.” Arrays can be nested; for example, “{{1, 2}, {3, 4, 5}}” is an array of
arrays of integers. The elements of an array can be accessed as follows:
>> {1.0, 2.3}(1)
2.3
which yields 2.3. Note that indexing begins at 0. Of course, if name is the name of a variable in scope
102 Ptolemy II