fprime-community / fpp

F Prime Prime: A modeling language for F Prime

F Prime Prime (FPP)

This repository contains the code and documentation for F Prime Prime (FPP for short). FPP is a modeling language for the F Prime flight software framework.

Contents

compiler: The FPP analysis and translation tools.

docs: The FPP User’s Guide and language specification.

editors: Syntax highlighting for code editors. Currently Vim and Emacs are supported here. There is also an FPP plugin available within Visual Studio Code.

Building and Installing

Tools

See compiler/README.adoc. To use or develop FPP in a standalone mode, you should install these tools. To use FPP as part of F Prime development, you can install the F Prime tool set, which includes FPP. See the F Prime installation instructions here.

Spec and User’s Guide

See docs/README.adoc. Build these documents from source only if you are developing them. Otherwise, read the copies available on the wiki.

Design and Implementation

See the wiki.

fpp's Issues

Number ports

Apply automatic numbering of ports

• Update algorithm in spec and on wiki
• Check output port numbers
• Apply matched numbering
• Apply general numbering
• Add tests

General updates to the User's Guide

Update Scope (section 1), Analyzing and Translating Models (Section 10), and any other sections to reflect the new capabilities in release 0.3.0.

Parameter XML

Generate XML for parameters.

Update fpp-locate-uses

Update fpp-locate-uses to cover topologies.

Document special ports

Add documentation for special ports.

Special port XML

Generate XML for special port instances.

Update fpp-locate-defs

Update fpp-locate-defs to cover topologies.

Update fpp-format

Extend fpp-format to cover topologies.

Check component instance specifiers

Extend fpp-check to cover component instance specifiers.

• Update algorithms on the wiki.
• Revise Enter Symbols, Check Uses, and Check Use Def Cycles.
• Define the Topology object and write a pass for checking topology defs.
• Check component instance specifiers.
• Add tests.

Check connection graph specifiers

Write the initial pass for checking connection graph specifiers. Don't resolve patterns yet. Don't check patterns for correctness, except to detect duplicate patterns and to resolve port instance identifiers.

Add optional header file to instance definitions

For example, you should be able to say

instance foo: Foo base id 0x100 at "../../Bar.hpp"

This definition says that foo is an instance of the Foo component and the C++ header file of its implementation is located at ../../Bar.hpp. This construction supports the case where a single component model has several different C++ implementation classes. If no path is given, e.g.,

instance foo: Foo base id 0x100

then the translator will use a default header file, e.g., Foo.hpp (or FooComponentImpl.hpp if that more verbose form is desired) in the directory where the Foo component model is located.

Tighten up checking for invalid uses of symbols

A few invalid uses of symbols cause a crash. For example this:

constant a = 0
constant b = a.c

In checking the second constant definition, the analyzer expects the symbol a to have an associated scope and throws an exception because it doesn't. Instead, it should report the error.

Tighten up the checks.

Check component instance definitions

Extend fpp-check to cover component instance definitions.

Check topology import specifiers

Extend fpp-check to cover topology import specifiers.

Add XML code gen for types defined in components

Mangle the names. For example, when enum E is defined inside component C, generate an XML array C_EArrayAi.ml. It would be better to define an inner class C::E, but the F Prime XML doesn't support this.

Parameter FPP from XML

Translate XML to FPP for parameters.

Fix XML code gen for port return type

The XML type needs the full qualified C++ type, e.g. Fw::ParamValid. This is due to the way the XML to C++ code generator works: the literal return type is pasted into the generated code, which may be in a different namespace.

Document include specifiers in components

Add documentation for include specifiers in components.

Document commands

Add documentation for commands.

Command XML

Generate XML for commands.

Document parameters

Add documentation for parameters.

Document telemetry

Add documentation for telemetry.

Check unused port specifiers

Write the initial pass for checking unused port specifiers. Resolve each specifier to a semantic port instance identifier.

Revise automatic numbering

Generalize the scheme so that you can specify any pair of matching port arrays P1 and P2 for any component C. Then for all instances I of C, and for all instances I' that have connections to I.P1[n1] and I.P2[n2] the renumbering will ensure that n1 = n2. This handles all the special cases listed (command registration, dispatch, and response; sequence command and response; health ping send and receive). It also extends to new cases.

This will require a new kind of component specifier for matching. For example, in the Health component:

match pingIn with pingOut

• Revise spec
• Add syntax to components
• Check semantics for new syntax
• Add tests

Add cpp code gen for constants defined in components

Mangle the names. For example, if constant c is defined in component C, generate a constant named C_c. It would be better to generate a constant C::c, but the F Prime XML doesn't support this.

Event FPP from XML

Translate XML to FPP for events.

Telemetry XML

Generate XML for telemetry channels.

Revise semantics of ref formal parameters in ports

Allow the use of ref port parameters in an async context. In this case, ref should be a no-op. In the current XML implementation, it affects the way the autocode is generated. We can note this as an XML limitation in the User's Guide.

• Revise spec
• Revise implementation and tests
• Revise User's Guide

General port instance XML

Generate XML for general port instances.

Document events

Add documentation for events.

Telemetry FPP from XML

Translate XML to FPP for telemetry.

Document general ports

Add documentation for general ports.

Resolve partially numbered topologies

Resolve each topology definition to a partially numbered topology T.

• Compute the instances of T.
• Compute the connection graphs based on imported connections and directly specified connections.
• Resolve pattern specifiers.
• Add tests.

Suppress generation of XML imports for built-in types

For example, uses of FwOpcodeType should not generate an import_header declaration.

Document internal ports

Add documentation for internal ports.

Revise behavior of fpp-locate-defs for included files

When file A includes file B, and a definition appears in B, the location of the definition should be A, not B.

Internal Port FPP from XML

Translate XML to FPP for internal ports.

Check init specifiers

Extend fpp-check to cover init specifiers.

Tighten up numeric format specifiers

Right now you can use an integer or rational format specifier for any numeric argument. Tighten this up so you can use integer specifiers for integer arguments and rational specifiers for floating-point arguments. For example, you can't use the specifier {x} for an argument of type F32 or the specifier {f} for an argument of type U32.

Command FPP from XML

Translate XML to FPP for commands.

Tighten up connection patterns

• Fix the set of available patterns in the language spec. Don't make it depend on the translation context.
• Make the pattern selector a keyword, not a number or enumeration constant.
• Add a telemetry pattern.

Push out 0.3.0 release

• Run static analysis
• Fix issues
• Release notes
• Release

Special Port Instance FPP from XML

Translate XML to FPP for special port instances.

Event XML

Generate XML for events.

General port instance FPP from XML

Translate general port instances to XML. Also translate top-level component structure and comment.

Internal port XML

Generate XML for internal ports

Document constants and types in components

Add documentation for constants and types in components.

Compute unconnected ports

• Revise spec and syntax: remove "declared unconnected" ports. This is too hard to maintain the FPP source and is not necessary.
• Compute the unconnected ports for each topology.
• Add an option to fpp-check to write out the unconnected ports
• Add tests.

With regard to the first item: The purpose of declared unconnected ports was to suppress warnings, so that every compilation would not spew warnings when ports are unconnected. However, we solve this problem by generating the unconnected list only on demand, via fpp-check -u [file]. One can then filter the unconnected list however desired, e.g., by piping it through egrep -vi '(pingin|pingout)'.

The alternative is to maintain long lists of unconnected ports in the source model, which is a pain, or provide some more advanced capability for specifying sets of ports, which is more complicated.

Update README

Update the README file to reflect the new capabilities in release 0.3.0.

Add abstract type definitions inside components

For completeness, along with arrays, structs, and enums.

• Spec
• Syntax
• Semantics
• Code gen