IBM Streams 4.3.0
SPL language elements
Some elements of the Streams Processing Language (SPL) are similar to the concepts and syntax of traditional programming languages, such as types and expressions. But the design of SPL is focused on processing streaming data.
SPL contains the following elements:
- Types
- The lowest-level element of the language. SPL supports many primitive data types, such as Boolean and integral, and composite data types, such as collections and tuples.
- Expressions
- Expressions in SPL are similar to expressions in typical imperative or functional languages.
- Statements
- Statements are the traditional building blocks of imperative languages. You can use them inside operator logic and function definitions.
- Functions
- The function declaration syntax in SPL is similar the function
declaration syntax in the C++ programming language. The return type
is first, followed by the function name and then the list of parameters
inside parentheses.
Functions are called from expressions. You can write functions in SPL, C++, or Java™. Functions that are written in C++ or Java are called native functions. Both kinds of functions can be invoked from the same SPL syntax.
- Clauses
- The body of an operator invocation is separated into clauses, for example, config and param. Clauses provide the details about how the operator works for specific operator invocations.