Description:

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

Unless multi-threaded 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-casted 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	Time	time	./.	Returns the result of MTime .
DateTime	MTime	mt	./.	Returns the result of MTime .
DateTime	CTime	ct	./.	Returns the result of CTime .
DateTime	ATime	at	./.	Returns the result of ATime .
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 122 of file fileexpressions.hpp.

#include <fileexpressions.hpp>

Collaboration diagram for FileExpressions:

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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 ()

ALIB_API SPFileFilter	CreateFilter (const String &expressionString)

Field Details:

◆ compiler

Compiler compiler

The expression compiler.

Definition at line 194 of file fileexpressions.hpp.

◆ plugin

Plugin plugin

The file expression Plugin.

Definition at line 195 of file fileexpressions.hpp.

Constructor(s) / Destructor Details::

◆ FileExpressions()

FileExpressions ( )

Default constructor.

Definition at line 209 of file fileexpressions.cpp.

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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 217 of file fileexpressions.cpp.

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