3 A Cross-Reference Tool

3.1 A Cross-Reference Tool (exref)

The exref tool has some limitations and is no longer supported. Please consider using the new cross reference tool xref.

exref is an incremental cross reference tool which builds a cross reference graph for selected modules. Information such as module dependencies and usage graphs can be derived from the cross reference graph produced by exref.

A function vertex is represented as: .

{{Mod, Fun, Arity}, {Type, File, Line}}

In this representation, the Type argument equals:

local | exported | {exported, compiler} | {local, compiler} | {Void(), record} 

A call edge is represented as:

{EdgeId, {Mod1, Fun1, Arity1}, {Modd2, Fun2, Arity2}, Line}

The following functions are available for configuring and using the cross reference tool:

• start() -> {ok, Pid} | {error, {already_started, Pid}} starts the exref server. The server must be started before any other functions in module exref can be used.


• stop() -> stopped stops the exref server.


• module(Module) -> true loads the specified module, or modules, into the cross reference graph.


• module(Module, Options) -> true loads the module Module into the cross reference graph. Module may also be a list of modules. Type can be any of the following:
  1. module = atom() | [atom()]
  
  
  2. Options = [Option], where
  
  
  3. Option = search | verbose | auto | warnings | recursive, where
  
  
  • search searches for source file in code path and replaces the path X/ebin with X/src.
  
  
  • verbose creates an output of module names during loading.
  
  
  • auto includes all referenced modules in the graph, with the exception of modules listed in the excludes(Modules) function shown below.
  
  
  • warnings emits warnings about the application and the spawning of variables. The reason for this is that apply calls lead to an incomplete graph for variable modules or functions. The apply call is inserted into the graph instead of the actual call. The same applies to spawn.
  
  
  • recursive recursively includes all files in a directory.
  
  


• directory(Directory) loads all modules in a directory into the cross reference graph.


• directory(Directory, Module) loads specific modules from a directory other than the current directory into the cross reference graph.


• directory(Directory, Module, Options) loads specific modules from a directory other than the current directory into the cross reference graph.


• delete_module(Module) deletes a module from the cross reference path. Module can be a list of modules.


• excludes(Modules) excludes a module, or list of modules, from the cross reference path.


• includes(Dirs) specifies where to search for Erlang include files.


• defs(Defs) adds definitions to be used when processing source code. This function appends the definitions specified with Defs to the definition list used by erl_pp.


• analyse(Type [,Arg]) -> Result analyses the cross reference graph and returns an Erlang term of a format which depends on the Type specified. The result from this analysis can be pretty printed with the pretty/1 function listed below. Some of Type can have optional arguments. Refer to the Reference Manual, the section tools, module exref for details.


• pretty(AnalyseResult) -> ok prints a verbose textual representation of the analysis result produced by the analyse/2 function shown above. The result produced from a user defined analysis cannot be used as input to this function.