Programación basada en comandos

Esta secuencia de artículos sirve como introducción y referencia para el marco basado en comandos WPILib.

Para obtener una colección de proyectos de ejemplo que utilizan el marco basado en comandos, consulte Ejemplos basados en comandos.

• ¿Qué es la programación «basada en comandos»?
• Comandos
• Command Compositions
• Subsistemas
• Enlazando comandos a Triggers
• Estructuración de un proyecto de robot basado en comandos
• Organizing Command-Based Robot Projects
• El planificador de comandos
• Una discusión técnica sobre los comandos de C ++
• Control PID a través de subsistemas PID y comandos PID
• Creación de perfiles de movimiento a través de los subsistemas TrapezoidProfile y los comandos TrapezoidProfile
• Combinando Motion Profiling y PID Basado en Comandos

Passing Functions As Parameters

In order to provide a concise inline syntax, the command-based library often accepts functions as parameters of constructors, factories, and decorators. Fortunately, both Java and C++ offer users the ability to pass functions as objects:

Method References (Java)

In Java, a reference to a function that can be passed as a parameter is called a method reference. The general syntax for a method reference is object::method. Note that no method parameters are included, since the method itself is passed. The method is not being called - it is being passed to another piece of code (in this case, a command) so that that code can call it when needed. For further information on method references, see Method References.

Lambda Expressions (Java)

While method references work well for passing a function that has already been written, often it is inconvenient/wasteful to write a function solely for the purpose of sending as a method reference, if that function will never be used elsewhere. To avoid this, Java also supports a feature called «lambda expressions.» A lambda expression is an inline method definition - it allows a function to be defined inside of a parameter list. For specifics on how to write Java lambda expressions, see Lambda Expressions in Java.

Lambda Expressions (C++)

Advertencia

Due to complications in C++ semantics, capturing this in a C++ lambda can cause a null pointer exception if done from a component command of a command composition. Whenever possible, C++ users should capture relevant command members explicitly and by value. For more details, see here.

C++ lacks a close equivalent to Java method references - pointers to member functions are generally not directly usable as parameters due to the presence of the implicit this parameter. However, C++ does offer lambda expressions - in addition, the lambda expressions offered by C++ are in many ways more powerful than those in Java. For specifics on how to write C++ lambda expressions, see Lambda Expressions in C++.