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Mapping Slice Sequences to Ruby Arrays
A Slice sequence maps to a Ruby array; the only exception is a sequence of bytes, which maps to a string. The use of a Ruby array means that the mapping does not generate a separate named type for a Slice sequence. It also means that you can take advantage of all the array functionality provided by Ruby. For example:
sequence<Fruit> FruitPlatter;
We can use the FruitPlatter sequence as shown below:
platter = [ Fruit::Apple, Fruit::Pear ] platter.push(Fruit::Orange)
The Ice run time validates the elements of a sequence to ensure that they are compatible with the declared type; a TypeError exception is raised if an incompatible type is encountered.
Mapping for Byte Sequences in Ruby
A Ruby string can contain arbitrary 8-bit binary data, therefore it is a more efficient representation of a byte sequence than a Ruby array in both memory utilization and throughput performance.
When receiving a byte sequence (as the result of an operation, as an out parameter, or as a member of a data structure), the value is always represented as a string. When sending a byte sequence as an operation parameter or data member, the Ice run time accepts both a string and an array of integers as legal values. For example, consider the following Slice definitions:
// Slice
sequence<byte> Data;
interface I {
void sendData(Data d);
Data getData();
};
The interpreter session below uses these Slice definitions to demonstrate the mapping for a sequence of bytes:
> proxy = ...
> proxy.sendData("\0\1\2\3") # Send as a string
> proxy.sendData([0, 1, 2, 3]) # Send as an array
> d = proxy.getData()
> d.class
=> String
> d
=> "\000\001\002\003"
The two invocations of sendData are equivalent; however, the second invocation incurs additional overhead as the Ice run time must validate the type and range of each array element.