Description:

This class implements an ALib Expression Compiler Plugin and thus enables "run-time expressions" to work with nodes of FTree

Unless multithreaded use is planned, an application should create one singleton of this class.

Method CreateFilter creates an object of inner type FileExpressions::Filter, which implements the FFilter interface used with scan parameters of function ScanFiles. This allows run-time evaluation of filter rules, for example rules coming from the command line, from configuration files or from interactive end-user input (hence from an UX/UI).

Of course the expression compiler can also be used directly without using the inner Filter class for evaluation and expressions do not need return a boolean "yes/no" result.

See also: For a quick tutorial, see the Programmer's Manual.

Implemented Expression Features

Compiler plug-in that provides expressions on filesystem entries, stored in nodes of class FTree.

All identifier and function names are defined case insensitive. Furthermore, the tokens are not hard-coded but resourced with ALib Camp singleton alib::FILES. With that, for example language translations might be performed.

Types:

This plug-in introduces the following types to the expression compiler:

Each types are auto-cast to Integer to allow all common operators, especially bitwise boolean operators.

Constants:

Type	Name	Min. Abbreviation	Description
Permissions	OwnerRead	ore	Used test result of function Permission.
Permissions	OwnerWrite	ow	Used test result of function Permission.
Permissions	OwnerExecute	oe	Used test result of function Permission.
Permissions	GroupRead	gr	Used test result of function Permission.
Permissions	GroupWrite	gw	Used test result of function Permission.
Permissions	GroupExecute	ge	Used test result of function Permission.
Permissions	OthersRead	otr	Used test result of function Permission.
Permissions	OthersWrite	otw	Used test result of function Permission.
Permissions	OthersExecute	ote	Used test result of function Permission.
Types	Directory	dir	Used to compare the result of function Type.
Types	SymbolicLinkDir	sld	Used to compare the result of function Type.
Types	Regular	reg	Used to compare the result of function Type.
Types	SymbolicLink	sl	Used to compare the result of function Type.
Types	Block	block	Used to compare the result of function Type.
Types	Character	character	Used to compare the result of function Type.
Types	Fifo	fifo	Used to compare the result of function Type.
Types	Socket	socket	Used to compare the result of function Type.

Constant Constructor Functions:

Return Type	Name	Min. Abbreviation	Signature	Description
Integer	KiloBytes	KB	int	Returns the given number multiplied with 2^10.
Integer	MegaBytes	MB	int	Returns the given number multiplied with 2^20.
Integer	GigaBytes	GB	int	Returns the given number multiplied with 2^30.
Integer	TeraBytes	TB	int	Returns the given number multiplied with 2^40.
Integer	PetaBytes	PB	int	Returns the given number multiplied with 2^50.
Integer	ExaBytes	EB	int	Returns the given number multiplied with 2^60.

Functions:

Return Type	Name	Min. Abbreviation	Signature	Description
String	Name	name	./.	Returns the file name.
Types	Type	ty	./.	Returns the result of Type.
Boolean	IsDirectory	isdir	./.	Returns the result of IsDirectory.
Boolean	IsSymbolicLink	issl	./.	Returns the result of IsSymbolicLink.
Integer	Size	size	./.	Returns the result of Size.
DateTime	Date	timestamp	./.	Returns the result of MDate.
DateTime	MDate	md	./.	Returns the result of MDate.
DateTime	BDate	bd	./.	Returns the result of BDate.
DateTime	CDate	cd	./.	Returns the result of CDate.
DateTime	ATime	ad	./.	Returns the result of ADate.
Permissions	Permissions	perm	./.	Returns the result of Permissions.
TOwnerAndGroupID	Owner	owner	./.	Returns the result of Owner.
TOwnerAndGroupID	Group	group	./.	Returns the result of Group.
TOwnerAndGroupID	UserID	uid	./.	Returns the current user's ID (calls posix getuid()).
TOwnerAndGroupID	GroupID	gid	./.	Returns the current user's group ID (calls posix getgid()).

Definition at line 111 of file fileexpressions.hpp.

#include <fileexpressions.hpp>

Collaboration diagram for FileExpressions:

[legend]

Inner Type Index:
struct	FexScope

class	Filter

struct	Plugin

Public Field Index:
Compiler	compiler
	The expression compiler.

Plugin	plugin
	The file expression Plugin.

Public Method Index:
ALIB_API	FileExpressions ()
	Default constructor.

ALIB_API SPFileFilter	CreateFilter (const String &expressionString)

Field Details:

◆ compiler

Compiler compiler

The expression compiler.

Definition at line 180 of file fileexpressions.hpp.

◆ plugin

Plugin plugin

The file expression Plugin.

Definition at line 181 of file fileexpressions.hpp.

Constructor(s) / Destructor Details:

◆ FileExpressions()

FileExpressions ( )

Default constructor.

Definition at line 220 of file fileexpressions.cpp.

Here is the call graph for this function:

Method Details:

◆ CreateFilter()

SPFileFilter CreateFilter ( const String & expressionString )

Creates a file filter using the expression compiler of this instance.

Parameters

expressionString The expression string to filter files and directories.

Returns: A shared pointer to the dynamically allocated filter object.

Definition at line 228 of file fileexpressions.cpp.

The documentation for this class was generated from the following files: