Difference between revisions of "Eiffel Visitor Factory Tool"

Revision as of 11:04, 22 November 2006

1 Overview
2 Command-line Options
3 Sample Output
4 Information
5 Change Log

Overview

The Eiffel Visitor Factory Tool is a simple command line application to generate Eiffel visitor patterns based on Eiffel classes found at specified folder locations. It can generate an interface (deferred) and/or stub (effective) Eiffel classes in no time.

Command-line Options

By default the tool will look in the current working directory for Eiffel source files (*.e). If you want to specify alternative locations use the -i switch to specify relative or absolute directory or file paths. If you need to exclude files use the -ex switch to specify what files to exclude.

To exclude a files in the current directory that start with status you would call:

vfact -ex "status.*\.e$$" (Windows shell requires $$ to represent $)

You can optionally search all specified directories recursively using the -r switch.

For all other options please read the usage help using the -?

Sample Output

As an example of what the tool generates, imagine the tool running in a directory containing two classes - ERROR_A and ERROR_B:

class ERROR_A
    --
end

class ERROR_B
    --
end

Running the tool in with the default settings will produce an interface class:

deferred class
	GENERATED_VISITOR
 
feature -- Processing
 
	process_error_a (a_value: ERROR_A)
			-- Process object `a_error_a'.
		require
			is_valid: is_valid
			a_value_attached: a_value /= Void
			is_applicable_visitation_entity: is_applicable_visitation_entity (a_value)
		deferred
		end
 
	process_error_b (a_value: ERROR_B)
			-- Process object `a_error_b'.
		require
			is_valid: is_valid
			a_value_attached: a_value /= Void
			is_applicable_visitation_entity: is_applicable_visitation_entity (a_value)
		deferred
		end
 
feature -- Query
 
	is_valid: BOOLEAN is
			-- Determines if `Current' is in a validate state to permit processing
		do
			Result := True
		end
 
	is_applicable_visitation_entity (a_value: ANY): BOOLEAN is
			-- Determines if object instance `a_value' is applicable for a visitation
		require
			a_value_attached: a_value /= Void
		do
			Result := True
		end
 
end -- class {GENERATED_VISITOR}

And a stub class:

class
	GENERATED_VISITOR_IMPL
 
inherit
	GENERATED_VISITOR
		redefine
			process_error_a,
			process_error_b
		end
 
feature -- Processing
 
	process_error_a (a_value: ERROR_A)
			-- Process object `a_error_a'.
		do
			check not_impl: False end
		end
 
	process_error_b (a_value: ERROR_B)
			-- Process object `a_error_b'.
		do
			check not_impl: False end
		end
 
end -- class {GENERATED_VISITOR_IMPL}

You can run the tool with the -n option to change the name of the generated class. Stub classes are always generated with a _IMPL extension.

Another option, user data, allows you to generate a visitor that is passed a piece of user data. In this case you would use the -ud switch an specify the base class for the user data. Using this approach will generate features that have to be passed an entity to visit upon and a user data entity (this could be void.)

Using the following command line will produce the output below:

vfact -n MY_VISITOR -ud TEXT_PRINTER

deferred class
	MY_VISITOR [G -> TEXT_PRINTER]
 
feature -- Processing
 
	process_error_a (a_value: ERROR_A; a_data: G)
			-- Process object `a_value' using user data `a_data'.
		require
			is_valid: is_valid
			a_value_attached: a_value /= Void
			is_applicable_visitation_entity: is_applicable_visitation_entity (a_value)
			is_text_printer_valid: is_text_printer_valid (a_data)
		deferred
		end
 
	process_error_b (a_value: ERROR_B; a_data: G)
			-- Process object `a_value' using user data `a_data'.
		require
			is_valid: is_valid
			a_value_attached: a_value /= Void
			is_applicable_visitation_entity: is_applicable_visitation_entity (a_value)
			is_text_printer_valid: is_text_printer_valid (a_data)
		deferred
		end
 
feature -- Query
 
	is_valid: BOOLEAN is
			-- Determines if `Current' is in a validate state to permit processing
		do
			Result := True
		end
 
	is_applicable_visitation_entity (a_value: ANY): BOOLEAN is
			-- Determines if object instance `a_value' is applicable for a visitation
		require
			a_value_attached: a_value /= Void
		do
			Result := True
		end
 
	is_text_printer_valid (a_data: G): BOOLEAN is
			-- Determines if data `a_data' is valid for Current.
		do
			Result := True
		end

class
	MY_VISITOR_IMPL [G -> TEXT_PRINTER]
 
inherit
	MY_VISITOR [G]
		redefine
			process_error_a,
			process_error_b
		end
 
feature -- Processing
 
	process_error_a (a_value: ERROR_A; a_data: G)
			-- Process object `a_error_a' using user data `a_data'.
		do
			check not_impl: False end
		end
 
	process_error_b (a_value: ERROR_B; a_data: G)
			-- Process object `a_error_b' using user data `a_data'.
		do
			check not_impl: False end
		end
 
end -- class {MY_VISITOR_IMPL}