Class AlangRegex

Represents an expression in the Alang (Automata language) used for defining finite-state automata. AlangRegex has a one-to-one correspondence with Finite State Automata.

Inheritance

object

AlangRegex

BinaryRegex

EmptyLang

Symbol

UnaryRegex

Wildcard

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Automata.Core.Alang

Assembly: Automata.Core.dll

Syntax

public abstract class AlangRegex

Remarks

The Alang language is a domain-specific language designed for defining and working with finite-state automata. This class serves as the starting point for parsing Alang expressions with Parse(string). For more information about the Alang language, see the Alang Grammar Specification.

Constructors

AlangRegex()

Initializes a new instance of the AlangRegex class.

Declaration

protected AlangRegex()

Properties

AlangExpressionString

String representation of this expression in valid Alang language syntax.

Declaration

public abstract string AlangExpressionString { get; }

Property Value

Type	Description
string	A string representing the expression in Alang syntax.

IsEmptyString

Indicates whether this expression is an empty string. An empty string is not a valid expression in Alang. Used internally by the Parser to handle empty strings.

Declaration

public bool IsEmptyString { get; }

Property Value

Type	Description
bool	true iff this expression is an empty string; otherwise, false.

Precedence

Precedence level of this expression according to the Alang grammar specification.

Declaration

public abstract int Precedence { get; }

Property Value

Type	Description
int	An integer representing the precedence level of the expression.

Methods

Compile()

Compiles this AlangRegex into an automaton. A new Alphabet for the automaton is created containing all referenced symbols.

Declaration

public Mfa Compile()

Returns

Type	Description
Mfa	An Mfa representing the compiled finite state automaton.

Remarks

This method creates a new Alphabet.

When possible, consider using a shared single alphabet for multiple automata, for added performance.

Compile(Alphabet)

Compiles this AlangRegex into an automaton using the specified alphabet.

Declaration

public Mfa Compile(Alphabet alphabet)

Parameters

Type	Name	Description
Alphabet	alphabet	The alphabet to use for compilation.

Returns

Type	Description
Mfa	An Mfa representing the compiled finite state automaton.

Remarks

The alphabet is extended with any symbols not currently in it.

Compile(string)

Compiles the specified regex string directly into a finite-state automaton. A new Alphabet for the automaton is created, containing all symbols in the regex string.

Declaration

public static Mfa Compile(string regexString)

Parameters

Type	Name	Description
string	regexString	A regex string on Alang format.

Returns

Type	Description
Mfa	An Mfa representing the compiled automaton.

Remarks

When possible, consider using a shared single alphabet for multiple automata, for added performance.

Exceptions

Type	Condition
AlangFormatException	Thrown when the regex string is in invalid format.

Compile(string, params string[])

Compiles the specified regex string directly into a finite-state automaton. A new Alphabet for the automaton is created, containing all symbols in the regex string and the specified additional symbols.

Declaration

public static Mfa Compile(string regexString, params string[] addSymbols)

Parameters

Type	Name	Description
string	regexString	A regex string on Alang format.
string[]	addSymbols	Additional symbols to include in the alphabet.

Returns

Type	Description
Mfa	An Mfa representing the compiled automaton.

Remarks

All alphabet symbols will be included in generic constructs, such as '.' (Wildcard) and '~' (Complement)

When possible, consider using a shared single alphabet for multiple automata, for added performance.

Exceptions

Type	Condition
AlangFormatException	Thrown when the regex string is in invalid format.

Compile(params string[])

Compiles this AlangRegex into an automaton. A new Alphabet for the automaton is created, containing all referenced symbols and the specified additional symbols.

Declaration

public Mfa Compile(params string[] addSymbols)

Parameters

Type	Name	Description
string[]	addSymbols	Additional symbols to include in the alphabet.

Returns

Type	Description
Mfa	An Mfa representing the compiled finite state automaton.

Remarks

All alphabet symbols will be included in generic constructs, such as '.' (Wildcard) and '~' (Complement)

When possible, consider using a shared single alphabet for multiple automata, for added performance.

DescendantsAndSelf()

Returns this expression and all its descendant expressions in a depth-first order.

Declaration

public IEnumerable<AlangRegex> DescendantsAndSelf()

Returns

Type	Description
IEnumerable<AlangRegex>	An IEnumerable<T> of AlangRegex representing this expression and all its descendants.

Param(AlangRegex, AlangRegex)

Returns the string of the given expression, enclosed in parentheses only if necessary based on operator precedence.

Declaration

protected static string Param(AlangRegex expr, AlangRegex parent)

Parameters

Type	Name	Description
AlangRegex	expr	The expression to get the string representation of.
AlangRegex	parent	The parent expression of expr.

Returns

Type	Description
string	The expression string, potentially enclosed in parentheses.

Remarks

Parentheses are added if the precedence of the given expression is lower than the precedence of the parent.

Parse(string)

Parses the specified regex string into an AlangRegex.

Declaration

public static AlangRegex Parse(string regexString)

Parameters

Type	Name	Description
string	regexString	A regex string on Alang format.

Returns

Type	Description
AlangRegex	An AlangRegex representing the parsed expression.

Exceptions

Type	Condition
AlangFormatException	Thrown when the regex string is in invalid format.

ToString()

String that represents the current expression in Alang format.

Declaration

public override string ToString()

Returns

Type	Description
string	The expression string of this expression in Alang format.

Overrides

object.ToString()