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Find details on the SPL language, toolkits, APIs, commands, and more.
Streams Processing Language (SPL)
Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
Operators
Operators process tuples in an incoming stream and produce an output stream as a result. SPL supports two kinds of operators: primitive operators and composite operators. A primitive operator is written in C++ or Java™. A composite operator is written in SPL and contains a reusable stream subgraph.
Operator definitions
A stream operator can be invoked to transform input streams to output streams. SPL supports two kinds of operators: primitive operators and composite operators.
Operator parameters
Different invocations of the same operator can yield different expansions, by providing actual parameter values for formal parameter placeholders declared in the operator definition.

Welcome
Learn about the core capabilities of Teracloud® Streams, its architecture, and key concepts.
Installing
Use this information to install, upgrade, and uninstall the Teracloud® Streams product.
Configuring
Create a basic or an enterprise domain which is a single point for configuring and managing common resources, security, and instances.
Administering
Administer the product by using the Teracloud® Streams graphical user interface, APIs, or the streamtool command-line interface.
Developing
Develop stream applications with the Streams Processing Language (SPL), Java, and Python.
Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
- APIs
  Application programming interfaces (APIs) provide functions that simplify applications development.
- Job configuration overlays
  You can specify or change configuration parameters when you use the submitjob or updateoperators operations. The settings control submission constraints, host constraints and locations, and operator status. Parameters are captured and updated in the configuration JSON file. When you change the values in the job configuration overlay file, the changes override any previously set values.
- Commands
  Teracloud® Streams provides a number of commands you use to perform tasks.
- Operator model
  An operator model is an XML document that describes the basic properties of a primitive operator.
- Streams Processing Language (SPL)
  Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
  - Language overview
    SPL contains types, expressions, statements, functions, clauses, and other elements of a programming language.
  - Grammar notation
    This language specification adopts a flavor of Backus-Naur Form (BNF) to describe the syntax of language features.
  - Lexical syntax
    SPL defines a set of rules to determine the syntax of a program.
  - Grammar overview
    Here is the SPL grammar syntax, with references to the sections that contain the semantics.
  - Expression language
    Though SPL is a streaming language, there are many places where it uses expressions that are found in traditional imperative or functional languages.
  - Annotations
    Operators can be annotated. Annotations influence the run time behavior of stream applications.
  - Types
    SPL has several primitive types that are tailored for streaming, and a few composite types that are inspired by scripting languages but statically checked. The following topics describe the types, how to define them, and how to convert values between different types.
  - Operators
    Operators process tuples in an incoming stream and produce an output stream as a result. SPL supports two kinds of operators: primitive operators and composite operators. A primitive operator is written in C++ or Java™. A composite operator is written in SPL and contains a reusable stream subgraph.
    - Operator invocations
      The purpose of SPL is to allow users to create streams of data, which are connected and manipulated by operator invocations.
    - Operator definitions
      A stream operator can be invoked to transform input streams to output streams. SPL supports two kinds of operators: primitive operators and composite operators.
      - Stream and operator instance names
        SPL has rules for giving names to operators, operator instances, streams, and ports.
      - Composite operators
        A composite operator is implemented in the Streams Processing Language (SPL) and encapsulates a subgraph of a data flow graph that can be parameterized to make it reusable in multiple stream applications.
      - Operator parameters
        Different invocations of the same operator can yield different expansions, by providing actual parameter values for formal parameter placeholders declared in the operator definition.
        Operators as parameters to composite operators
        A composite operator encapsulates a subgraph and some of the operators in that subgraph can be given to the composite operator as parameters at the time of invocation.
        Other operator parameters
        Both composite and primitive operators can be customized by parameters such as the name of an attribute in an input port, or an expression to be used to filter data.
        Operator parameter passing semantics
        Operator parameters in SPL behave similarly to macro expansion, but the semantics are designed to prevent macro mistakes common in languages like C.
        Operator parameter modes
        A parameter declaration in a composite operator definition must specify an expression mode, and can optionally specify a default value.
      - Primitive operators
        A primitive operator is an operator that is implemented in the C++ or Java™ and that includes an operator model that describes the syntax and semantics of the operator.
  - Program structure
  - Operator config clause
    The config clause specifies hints and directives that influence how the compiler builds an operator invocation, or how the runtime system runs it.
- Toolkits
  A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
- SPLDOC markup
  You can use SPLDOC markup in the descriptions associated with the SPL artifacts in a toolkit. The spl-make-doc command generates HTML documentation from the marked up artifacts.
Glossary
Use this glossary to find terms and definitions for Teracloud® Streams.

Operator parameters

Different invocations of the same operator can yield different expansions, by providing actual parameter values for formal parameter placeholders declared in the operator definition.