Grammar Class

Namespace:: ActiproSoftware.Text.Parsing.LLParser.Implementation

Assembly:: ActiproSoftware.Text.LLParser.Wpf.dll

Represents a grammar that can be used with a recursive descent parser.

public class Grammar : IKeyedObject

Inheritance:: object object

Derived:: DotNetGrammarBase JavaScriptGrammar JsonGrammar PythonGrammar XmlGrammar

Implements:: IKeyedObject

Constructors

Grammar(string)

Initializes a new instance of the Grammar class.

public Grammar(string key)

Parameter	Type	Description
key	string	A string that identifies the grammar, generally the related language name.

Properties

IsCompiled

Gets whether the grammar and its elements are compiled, via a call to its Compile() method.

public bool IsCompiled { get; }

Property Value

bool:: true if the grammar and its elements are compiled; otherwise, false.

Key

Gets the string that identifies the grammar, generally the related language name.

public string Key { get; }

Property Value

string:: The string that identifies the grammar, generally the related language name.

NonTerminals

Gets a dictionary of all non-terminals defined in the grammar, with the key being the non-terminal string key.

public IDictionary<string, NonTerminal> NonTerminals { get; }

Property Value

IDictionary<string, NonTerminal>:: A dictionary of all non-terminals defined in the grammar, with the key being the non-terminal string key.

Remarks

This property returns null until the grammar has been compiled.

Root

Gets or sets the root NonTerminal of the grammar, meaning the first non-terminal that is attempted to be matched when parsing begins.

public NonTerminal Root { get; set; }

Property Value

NonTerminal:: The root NonTerminal of the grammar.

Remarks

Once the grammar has been compiled, the setter of this property will throw an exception if called.

Terminals

Gets a dictionary of all terminals defined in the grammar, with the key being the terminal string key.

public IDictionary<string, Terminal> Terminals { get; }

Property Value

IDictionary<string, Terminal>:: A dictionary of all terminals defined in the grammar, with the key being the terminal string key.

Remarks

This property returns null until the grammar has been compiled.

Methods

Ast(string, params ITreeConstructionNode[])

Creates an ITreeConstructionNode that generates an IAstNode with the specified value and optional child nodes.

public static ITreeConstructionNode Ast(string value, params ITreeConstructionNode[] childNodes)

Parameter	Type	Description
value	string	The value to assign to the generated IAstNode.
childNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstChildFrom(string)

Creates an ITreeConstructionNode that generates an IAstNode from the first child of an IAstNodeMatch that has the specified label.

public static ITreeConstructionNode AstChildFrom(string label)

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstChildFrom(string, int)

Creates an ITreeConstructionNode that generates an IAstNode from the specified child of an IAstNodeMatch that has the specified label.

public static ITreeConstructionNode AstChildFrom(string label, int childIndex)

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.
childIndex	int	The index of the child.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstChildrenFrom(string)

Creates an ITreeConstructionNode that generates an IAstNode from the children of an IAstNodeMatch that has the specified label.

public static ITreeConstructionNode AstChildrenFrom(string label)

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstChildrenFrom(string, int)

Creates an ITreeConstructionNode that generates an IAstNode from the descendants at the specified nesting level of an IAstNodeMatch that has the specified label, useful for gathering desired nodes two or more levels deep.

public static ITreeConstructionNode AstChildrenFrom(string label, int nestingLevel)

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.
nestingLevel	int	The zero-based target nesting level, where `0` means direct children.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstConditional(string, params ITreeConstructionNode[])

Creates an ITreeConstructionNode that generates an IAstNode with the specified value and optional child nodes, but only if there is more than one child available. If one child is available, it is directly returned.

public static ITreeConstructionNode AstConditional(string value, params ITreeConstructionNode[] childNodes)

Parameter	Type	Description
value	string	The value to assign to the generated IAstNode.
childNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstConditionalFrom(string, string)

Creates an ITreeConstructionNode that generates an IAstNode with the specified value and child nodes from the children of an IAstNodeMatch that has the specified label, but only if there is at least one child available.

public static ITreeConstructionNode AstConditionalFrom(string value, string label)

Parameter	Type	Description
value	string	The value to assign to the generated IAstNode.
label	string	The IAstNodeMatch for which to search.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstConditional<TAstNode>(params ITreeConstructionNode[])

Creates an ITypedTreeConstructionNode<TAstNode> that generates an IAstNode of the specified type, but only if there is more than one child available. If one child is available, it is directly returned.

public static ITypedTreeConstructionNode<TAstNode> AstConditional<TAstNode>(params ITreeConstructionNode[] childNodes) where TAstNode : class, IAstNode, new()

Type Parameters:: TAstNode -

Parameter	Type	Description
childNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITypedTreeConstructionNode<TAstNode>:: The ITypedTreeConstructionNode<TAstNode> that was created.

AstCount(params ITreeConstructionNode[])

Creates an ITreeConstructionNode that generates an IAstNode whose value is the count of IAstNode objects generated by contained nodes.

public static ITreeConstructionNode AstCount(params ITreeConstructionNode[] countNodes)

Parameter	Type	Description
countNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstFrom(string)

Creates an ITreeConstructionNode that generates an IAstNode from an IAstNodeMatch that has the specified label.

public static ITreeConstructionNode AstFrom(string label)

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstFrom<TAstNode>(string)

Creates an ITypedTreeConstructionNode<TAstNode> that generates an IAstNode of the specified type from an IAstNodeMatch that has the specified label.

public static ITypedTreeConstructionNode<TAstNode> AstFrom<TAstNode>(string label) where TAstNode : class, IAstNode

Type Parameters:: TAstNode -
The type of IAstNode-based class to create.

Parameter	Type	Description
label	string	The IAstNodeMatch for which to search.

Returns

ITypedTreeConstructionNode<TAstNode>:: The ITypedTreeConstructionNode<TAstNode> that was created.

AstLeftAssociativity<TAstNode, TDerivedAstNode>(ITreeConstructionNode, Expression<Func<TDerivedAstNode, TAstNode>>, Expression<Func<TDerivedAstNode, TAstNode>>, Func<TDerivedAstNode, TDerivedAstNode, bool>)

Creates an ITypedTreeConstructionNode<TAstNode> that attempts to make a child node left associative instead of right associative, useful for scenarios such as binary operators.

public static ITypedTreeConstructionNode<TAstNode> AstLeftAssociativity<TAstNode, TDerivedAstNode>(ITreeConstructionNode childNode, Expression<Func<TDerivedAstNode, TAstNode>> leftPropExpression, Expression<Func<TDerivedAstNode, TAstNode>> rightPropExpression, Func<TDerivedAstNode, TDerivedAstNode, bool> condition) where TAstNode : class, IAstNode where TDerivedAstNode : class, TAstNode

Type Parameters:: TAstNode -
The type of IAstNode-based class to return.

TDerivedAstNode -
The type of IAstNode (that must inherit TAstNode) that supports associativity.

Parameter	Type	Description
childNode	ITreeConstructionNode	The child ITreeConstructionNode object.
leftPropExpression	Expression<Func<TDerivedAstNode, TAstNode>>	The lambda expression indicating the property for the left side branch.
rightPropExpression	Expression<Func<TDerivedAstNode, TAstNode>>	The lambda expression indicating the property for the right side branch.
condition	Func<TDerivedAstNode, TDerivedAstNode, bool>	The optional lambda expression that is passed both the root and child nodes and returns `true` if the associativity change is permitted.

Returns

ITypedTreeConstructionNode<TAstNode>:: The ITypedTreeConstructionNode<TAstNode> that was created.

AstValueOf(ITreeConstructionNode, params ITreeConstructionNode[])

Creates an ITreeConstructionNode that generates an IAstNode with the value of the specified ITreeConstructionNode's constructed node, and optional child nodes.

public static ITreeConstructionNode AstValueOf(ITreeConstructionNode valueOfNode, params ITreeConstructionNode[] childNodes)

Parameter	Type	Description
valueOfNode	ITreeConstructionNode	The ITreeConstructionNode whose constructed IAstNode value will be used.
childNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

AstValueOfConditional(ITreeConstructionNode, params ITreeConstructionNode[])

Creates an ITreeConstructionNode that generates an IAstNode with the value of the specified ITreeConstructionNode's constructed node, and optional child nodes, but only if there is more than one child available. If one child is available, it is directly returned.

public static ITreeConstructionNode AstValueOfConditional(ITreeConstructionNode valueOfNode, params ITreeConstructionNode[] childNodes)

Parameter	Type	Description
valueOfNode	ITreeConstructionNode	The ITreeConstructionNode whose constructed IAstNode value will be used.
childNodes	ITreeConstructionNode[]	The optional child ITreeConstructionNode objects.

Returns

ITreeConstructionNode:: The ITreeConstructionNode that was created.

Ast<TAstNode>()

Creates an ITypedTreeConstructionNode<TAstNode> that generates an IAstNode of the specified type.

public static ITypedTreeConstructionNode<TAstNode> Ast<TAstNode>() where TAstNode : class, IAstNode, new()

Type Parameters:: TAstNode -
The type of IAstNode-based class to create.

Returns

ITypedTreeConstructionNode<TAstNode>:: The ITypedTreeConstructionNode<TAstNode> that was created.

CanAlwaysMatch(IParserState)

Implements a ParserCanMatchCallback that always returns true, and is useful for assigning to non-terminals that are called from the Root non-terminal for a Grammar.

public static bool CanAlwaysMatch(IParserState state)

Parameter	Type	Description
state	IParserState	A IParserState that provides information about the parser's current state.

Returns

bool:: Always true.

Compile()

Compiles the grammar, which prepares the grammar and its elements for parsing usage.

public void Compile()

Remarks

Compiling the grammar also means that all elements of the language will be locked and no longer able to be modified.

ToEbnfString()

Outputs the contents of the grammar in EBNF form.

public string ToEbnfString()

Returns

string:: A string containing the EBNF form of the grammar.

Validate()

Validates that the grammar and its elements are configured correctly and ready to be compiled.

public void Validate()

Remarks

An exception will be thrown if validation fails.

In This Article

Grammar Class

Constructors

Grammar(string)

Properties

IsCompiled

Property Value

Key

Property Value

NonTerminals

Property Value

Remarks

Root

Property Value

Remarks

Terminals

Property Value

Remarks

Methods

Ast(string, params ITreeConstructionNode[])

Returns

AstChildFrom(string)

Returns

AstChildFrom(string, int)

Returns

AstChildrenFrom(string)

Returns

AstChildrenFrom(string, int)

Returns

AstConditional(string, params ITreeConstructionNode[])

Returns

AstConditionalFrom(string, string)

Returns

AstConditional<TAstNode>(params ITreeConstructionNode[])

Returns

AstCount(params ITreeConstructionNode[])

Returns

AstFrom(string)

Returns

AstFrom<TAstNode>(string)

Returns

AstLeftAssociativity<TAstNode, TDerivedAstNode>(ITreeConstructionNode, Expression<Func<TDerivedAstNode, TAstNode>>, Expression<Func<TDerivedAstNode, TAstNode>>, Func<TDerivedAstNode, TDerivedAstNode, bool>)

Returns

AstValueOf(ITreeConstructionNode, params ITreeConstructionNode[])

Returns

AstValueOfConditional(ITreeConstructionNode, params ITreeConstructionNode[])

Returns

Ast<TAstNode>()

Returns

CanAlwaysMatch(IParserState)

Returns

Compile()

Remarks

ToEbnfString()

Returns

Validate()

Remarks

Inherited Members