All nodes in a Loyc syntax tree share this base class. More...

Source file:

/Core/Loyc.Syntax/LNodes/LNode.cs

Inheritance diagram for Loyc.Syntax.LNode:

Remarks

All nodes in a Loyc syntax tree share this base class.

Loyc defines only three types of nodes: simple symbols, literals, and calls.

A IdNode is a simple identifier, such as a VariableName
A LiteralNode is a literal constant, such as 123 or "hello"
A CallNode encompasses all other kinds of nodes, such as normal function calls like f(x), generic specifications like f<x> (represented as @'of(f, x)), braced blocks of statements (represented as ‘’{}`(stmt1, stmt2, ...)), and so on.

See http://loyc.net/loyc-trees to learn more about the Loyc tree concept.

This class provides access to all properties of all three types of nodes, in order to make this class easier to access from plain C#, and to avoid unnecessary downcasting in some cases. In fact, you never need to use the derived classes; you can think of them simply as a way that the implementation is optimized.

Loyc nodes are immutable (except the Style property).

Important properties

The main properties of a node are

Attrs: holds the attributes of the node, if any.
Name: the name of an IdNode, or the name of the IdNode that is acting as the Target of a CallNode.
Value: the value of a LiteralNode.
Target: the target of a CallNode. It represents a method, macro, or special identifier that is being called.
Args: holds the arguments to a CallNode, if any. Returns an empty list if the node does not have an argument list.
Range: indicates the source file that the node came from and location in that source file.
Style: an 8-bit flag value that is used as a hint to the node printer about how the node should be printed. For example, a hex literal like 0x10 has the NodeStyle.Alternate style to distinguish it from decimal literals such as 16. Custom display styles that do not fit in the Style property can be expressed with attributes.

To learn more about working with LNode, see http://loyc.net/loyc-trees/dotnet.html

Nested classes
struct	PushedPrinter
	Returned by PushPrinter(ILNodePrinter). More...

Public Types
enum	CompareMode { Normal = 0, Styles = 1, IgnoreTrivia = 2 }

enum	ReplaceOpt { ReplaceOpt.ReplaceRoot = 1, ReplaceOpt.ProcessAttrs = 2, ReplaceOpt.Default = ReplaceRoot \| ProcessAttrs }

Public fields
virtual UString	TextValue => default(UString)
	If this node IsLiteral, gets the original text of the literal, if it is available. This property is empty if the node was created programmatically from a value, or if the parser did not save the original text, or if this is not a literal. More...

virtual Symbol	TypeMarker => null
	If this node IsLiteral, gets the type marker associated with the literal. This property is null if the node was created programmatically from a value, or if the parser did not save the type marker, or if this is not a literal. More...

Public static fields
static readonly EmptySourceFile	SyntheticSource = new EmptySourceFile("<Synthetic Code>")

static readonly IdNode	Missing = Id(CodeSymbols.Missing)
	The empty identifier, used to represent missing information. More...

static readonly LNode	InParensTrivia = Id(CodeSymbols.TriviaInParens)
	Used by the `quote {...}` macro. More...

Properties
virtual SourceRange	Range `[get]`
	Returns the location and range in source code of this node. More...

ISourceFile	Source `[get]`
	Returns the source file (shortcut for `Range.Source`). More...

NodeStyle	Style `[get, set]`
	Indicates the preferred style to use when printing the node to a text string. More...

NodeStyle	BaseStyle `[get, set]`

virtual LNodeList	Attrs `[get]`
	Returns the attribute list for this node. More...

virtual bool	IsFrozen `[get]`
	Returns true if the node is immutable, and false if any part of it can be edited. Currently, mutable nodes are not implemented. More...

abstract LNodeKind	Kind `[get]`
	Returns the LNodeKind: Symbol, Literal, or Call. More...

bool	IsCall `[get]`

bool	IsId `[get]`

bool	IsLiteral `[get]`

abstract Symbol	Name `[get]`
	Returns the Symbol if IsId. If this node is a call (IsCall) and `Target.IsId` is true, this property returns `Target.Name`. In all other cases, the name is GSymbol.Empty. Shall not return null. More...

bool	HasSpecialName `[get]`
	Returns true if Name is a "special" name (i.e. starts with '#' or '\'' or '.' or any character below 48 in ASCII). More...

bool	HasValue `[get]`

abstract object	Value `[get]`
	Returns the value of a literal node, or NoValue.Value if this node is not a literal (IsLiteral is false). More...

abstract LNode	Target `[get]`
	Returns the target of a method call, or null if IsCall is false. The target can be a symbol with no name (GSymbol.Empty) to represent a parenthesized expression, if there is one argument. More...

abstract LNodeList	Args `[get]`
	Returns the argument list of this node. Always empty when `IsCall==false`. More...

static ILNodePrinter??	Printer `[get, set]`
	Gets or sets the default node printer on the current thread, which controls how nodes are serialized to text by default. More...

virtual object	TriviaValue `[get]`
	Gets the value of `Args[0].Value`, if Args[0] exists; otherwise, returns NoValue.Value. More...

int	ArgCount `[get]`

int	AttrCount `[get]`

bool	HasAttrs `[get]`

bool	IsTrivia `[get]`

int	Min `[get]`

virtual int?	Max `[get]`

LNode	this[int index] `[get]`

int	Count `[get]`

Properties inherited from Loyc.Syntax.ILNode
LNodeKind	Kind `[get]`

Symbol	Name `[get]`

ILNode	Target `[get]`

ISourceRange	Range `[get]`

NodeStyle	Style `[get, set]`

Properties inherited from Loyc.Syntax.IUninterpretedLiteral
UString	TextValue `[get]`
	Represents the serialized text of the value. More...

Symbol	TypeMarker `[get]`
	Represents the type of the value. More...

Properties inherited from Loyc.IHasValue< object >
T	Value `[get]`

Properties inherited from Loyc.Collections.INegListSource< ILNode >
int	Min `[get]`
	Returns the minimum valid index in the collection. More...

int	Max `[get]`
	Returns the maximum valid index in the collection. More...

Properties inherited from Loyc.IHasLocation
object	Location `[get]`

Properties inherited from Loyc.Collections.INegListSource< LNode >
int	Min `[get]`
	Returns the minimum valid index in the collection. More...

int	Max `[get]`
	Returns the maximum valid index in the collection. More...

Public Member Functions
LNode	SetBaseStyle (NodeStyle s)

LNode	SetStyle (NodeStyle s)

virtual LNode	WithName (Symbol name)
	Creates a node with a new value for Name. More...

abstract LiteralNode	WithValue (object value)
	Creates a new literal node with a different Value than the current literal node. More...

virtual CallNode	WithTarget (LNode target)

virtual CallNode	WithTarget (Symbol name)

abstract CallNode	WithArgs (LNodeList args)
	Creates a Node with a new argument list. If this node is not a call, a new node is created using this node as its target. Otherwise, the existing argument list is replaced. More...

virtual CallNode	With (LNode target, LNodeList args)
	Creates a CallNode with the same attributes and Range, but a different target and argument list. If the current node is not a CallNode, it becomes one (the Range, Style and attributes of the current node are kept, but the Kind, Value, and Name are discarded.) More...

virtual CallNode	With (Symbol target, LNodeList args)
	Creates a CallNode with the same attributes and Range, but a different target and argument list. If the current node is not a CallNode, it becomes one (the Range, Style and attributes of the current node are kept, but the Kind, Value, and Name are discarded.) More...

CallNode	With (Symbol target, params LNode[] args)

abstract LNode	Clone ()
	Creates a copy of the node. Since nodes are immutable, there is little reason for an end-user to call this, but Clone() is used internally as a helper method by the WithXyz() methods. More...

LNode	WithRange (SourceRange range)

virtual LNode	WithRange (int startIndex, int endIndex)

LNode	WithStyle (NodeStyle style)

virtual LNode	With (SourceRange range, NodeStyle style)

virtual LNode	WithoutAttrs ()

abstract LNode	WithAttrs (LNodeList attrs)

LNode	WithAttrs (params LNode[] attrs)

CallNode	WithArgs (params LNode[] args)

LNode	PlusAttr (LNode attr)

LNode	PlusAttrs (IEnumerable< LNode > attrs)

LNode	PlusAttrs (params LNode[] attrs)

LNode	PlusAttrs (LNodeList attrs)

LNode	PlusAttrsBefore (LNodeList attrs)

LNode	PlusAttrsBefore (params LNode[] attrs)

LNode	PlusAttrBefore (LNode attr)

LNode	PlusArg (LNode arg)

LNode	PlusArgs (LNodeList args)

LNode	PlusArgs (IEnumerable< LNode > args)

LNode	PlusArgs (params LNode[] args)

LNode	WithArgChanged (int index, Func< LNode, LNode > selector)

LNode	WithArgChanged (int index, LNode newValue)

LNode	WithAttrChanged (int index, LNode newValue)

LNode	WithChildChanged (int index, LNode newValue)

abstract void	Call (LNodeVisitor visitor)

abstract void	Call (ILNodeVisitor visitor)

virtual string	Print (ParsingMode mode=null, ILNodePrinterOptions options=null)

override string	ToString ()

virtual bool	Equals (ILNode other, CompareMode mode)
	Compares two nodes for structural equality. Two nodes are considered equal if they have the same kind, the same name, the same value, the same arguments, and the same attributes. More...

bool	Equals (LNode other)

bool	Equals (ILNode other)

override bool	Equals (object other)

override int	GetHashCode ()
	Gets the hash code based on the structure of the tree. More...

bool	HasPAttrs ()

LNodeList	PAttrs ()

virtual bool	Calls (Symbol name, int argCount)
	Returns true if `Name == name` and `Max + 1 == argCount` (which implies `Kind == LNodeKind.Call` if argCount != -1). More...

virtual bool	Calls (string name, int argCount)

virtual bool	Calls (Symbol name)

virtual bool	Calls (string name)

virtual bool	CallsMin (Symbol name, int minArgCount)
	Returns true if this is a call with the specified name and the specified minimum number of arguments. More...

virtual bool	CallsMin (string name, int minArgCount)
	Returns true if this is a call with the specified name and the specified minimum number of arguments. More...

virtual bool	HasSimpleHead ()
	Returns true if this is not a call, or if the call's Target is an Id or a Literal. More...

virtual bool	HasSimpleHeadWithoutPAttrs ()
	Returns true if this is not a call, or if the call's Target is an Id or a Literal, and the Target has only trivia attributes. More...

virtual LNode	WithAttrs (Func< LNode, Maybe< LNode >> selector)

virtual LNode	WithAttrs (Func< LNode, IReadOnlyList< LNode >> selector)

virtual LNode	WithArgs (Func< LNode, Maybe< LNode >> selector)

virtual bool	IsIdWithoutPAttrs ()

virtual bool	IsIdWithoutPAttrs (Symbol name)

virtual bool	IsIdNamed (Symbol name)

virtual bool	IsIdNamed (string name)

CallNode	WithSplicedArgs (int index, LNode from, Symbol listName)

CallNode	WithSplicedArgs (LNode from, Symbol listName)

LNode	WithSplicedAttrs (int index, LNode from, Symbol listName)

LNode	WithSplicedAttrs (LNode from, Symbol listName)

NestedEnumerable< DescendantsFrame, LNode >	Descendants (NodeScanMode mode=NodeScanMode.YieldAllChildren)

NestedEnumerable< DescendantsFrame, LNode >	DescendantsAndSelf ()

LNode	TryGet (int index, out bool fail)

IRange< LNode >	Slice (int start, int count=int.MaxValue)

IEnumerator< LNode >	GetEnumerator ()

virtual LNode	Select (Func< LNode, Maybe< LNode >> selector, ReplaceOpt options=ReplaceOpt.ProcessAttrs)
	Transforms the Target, parameters, and optionally the attributes of an LNode, returning another LNode of the same Kind. If the selector makes no changes, Select() returns `this`. More...

virtual LNode	SelectMany (Func< LNode, IReadOnlyList< LNode >> selector, ReplaceOpt options=ReplaceOpt.ProcessAttrs)

Maybe< LNode >	ReplaceRecursive (Func< LNode, Maybe< LNode >> matcher, ReplaceOpt options=ReplaceOpt.Default)
	Performs a recursive find-and-replace operation, by attempting to replace each child (among Attrs, Target, Args) using the specified selector. This method can also be used for simple searching, by giving a selector that always returns null. More...

LNode	ReplaceRecursive (Func< LNode, LNode > matcher, ReplaceOpt options=ReplaceOpt.Default)

LNodeList	RecursiveReplace (Func< LNode, LNodeList?> matcher, ReplaceOpt options=ReplaceOpt.Default)

Public Member Functions inherited from Loyc.Collections.INegListSource< ILNode >
IRange< T >	Slice (int start, int count=int.MaxValue)
	Returns a sub-range of this list. More...

Public Member Functions inherited from Loyc.ICloneable< LNode >
T	Clone ()

Public Member Functions inherited from Loyc.Collections.INegListSource< LNode >
IRange< T >	Slice (int start, int count=int.MaxValue)
	Returns a sub-range of this list. More...

Static Public Member Functions
static IdNode	Id (Symbol name, LNode prototype)

static IdNode	Id (string name, LNode prototype)

static IdNode	Id (LNodeList attrs, Symbol name, LNode prototype)

static IdNode	Id (LNodeList attrs, string name, LNode prototype)

static LiteralNode	Literal< V > (V value, LNode prototype)

static LiteralNode	Literal< V > (LNodeList attrs, V value, LNode prototype)

static CallNode	Call (Symbol name, LNode prototype)

static CallNode	Call (LNode target, LNode prototype)

static CallNode	Call (Symbol name, LNodeList args, LNode prototype)

static CallNode	Call (LNode target, LNodeList args, LNode prototype)

static CallNode	Call (LNodeList attrs, Symbol name, LNodeList args, LNode prototype)

static CallNode	Call (LNodeList attrs, LNode target, LNodeList args, LNode prototype)

static CallNode	Trivia (Symbol name, object value, LNode prototype)

static IdNode	Id (Symbol name, SourceRange range, NodeStyle style=NodeStyle.Default)

static IdNode	Id (string name, SourceRange range, NodeStyle style=NodeStyle.Default)

static IdNode	Id (LNodeList attrs, Symbol name, SourceRange range, NodeStyle style=NodeStyle.Default)

static IdNode	Id (LNodeList attrs, string name, SourceRange range, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal< V > (V value, SourceRange range, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal (SourceRange range, LiteralValue value, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal< P > (SourceRange range, P valueProvider, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal< V > (LNodeList attrs, V value, SourceRange range, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal (LNodeList attrs, SourceRange range, LiteralValue value, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal< P > (LNodeList attrs, SourceRange range, P valueProvider, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, SourceRange range, int targetStart, int targetEnd, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNode target, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, LNodeList args, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, LNodeList args, SourceRange range, int targetStart, int targetEnd, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNode target, LNodeList args, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, Symbol name, LNodeList args, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, LNode target, LNodeList args, SourceRange range, NodeStyle style=NodeStyle.Default)

static CallNode	Trivia (Symbol name, object value, SourceRange range, NodeStyle style=NodeStyle.Default)

static IdNode	Id (Symbol name, ISourceFile file=null)

static IdNode	Id (string name, ISourceFile file=null)

static IdNode	Id (LNodeList attrs, Symbol name, ISourceFile file=null)

static IdNode	Id (LNodeList attrs, string name, ISourceFile file=null)

static LiteralNode	Literal< V > (V value, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal< V > (LNodeList attrs, V value, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static LiteralNode	Literal (object value, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNode target, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (Symbol name, LNodeList args, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNode target, LNodeList args, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, Symbol name, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, LNode target, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, Symbol name, LNodeList args, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Call (LNodeList attrs, LNode target, LNodeList args, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static CallNode	Trivia (Symbol name, object value, ISourceFile file=null, NodeStyle style=NodeStyle.Default)

static LNodeList	List ()

static LNodeList	List (LNode item_0)

static LNodeList	List (LNode item_0, LNode item_1)

static LNodeList	List (params LNode[] list)

static LNodeList	List (IEnumerable< LNode > list)

static LNodeList	List (VList< LNode > list)

static bool	IsSpecialName (string name)
	Returns true if `name` is considered a "special" name that starts with any character below 48 in ASCII, such as '#', '\'', and '.'. More...

static bool	IsSpecialName (Symbol name)

static SavedValue< ILNodePrinter >	SetPrinter (ILNodePrinter newValue)

static PushedPrinter	PushPrinter (ILNodePrinter printer)
	Helps you change printers temporarily. Usage in C#: `using (LNode.PushPrinter(myPrinter)) { ... }` More...

static bool	Equals (LNodeList a, LNodeList b, CompareMode mode=CompareMode.Normal)
	Compares two lists of nodes for structural equality. More...

static bool	Equals (ILNode a, ILNode b, CompareMode mode=CompareMode.Normal)

static LNode	MergeLists (LNode node1, LNode node2, Symbol listName)
	Some CallNodes are used to represent lists. This method merges two nodes, forming or appending a list (see remarks). More...

static LNode	MergeBinary (LNode node1, LNode node2, Symbol binaryOpName)
	Combines two nodes using a binary operator or function. More...

static List< LNode >	FlattenBinaryOpSeq (LNode expr, Symbol opName, bool? rightAssociative=null)
	Converts a sequence of the same operator (e.g. `x+y+z`) to a list (e.g. x, y, z). More...

Protected Member Functions
	LNode (LNode prototype)

	LNode (SourceRange range, NodeStyle style)

Static Protected Member Functions
static void	NoNulls (LNodeList list, string propName)

Protected fields
RangeAndStyle	RAS

Protected static fields
static readonly CallNode	EmptySplice = Call(CodeSymbols.Splice)

Member Enumeration Documentation

◆ ReplaceOpt

enum Loyc.Syntax.LNode.ReplaceOpt

strong

Enumerator
ReplaceRoot	When calling `n.ReplaceRecursive`, specifies that the selector should be called on `n` itself, not just its children.
ProcessAttrs	When calling ReplaceRecursive(Func<LNode, Maybe<LNode>>, ReplaceOpt) or Select(Func<LNode, Maybe<LNode>>, ReplaceOpt), specifies that attributes should be processed rather than left unchanged.
Default	ReplaceRoot and ProcessAttrs

Member Function Documentation

◆ Calls()

virtual bool Loyc.Syntax.LNode.Calls	(	Symbol	name,
		int	argCount
	)

inlinevirtual

Returns true if Name == name and Max + 1 == argCount (which implies Kind == LNodeKind.Call if argCount != -1).

This could have been an extension method, but when verifying that you have a certain kind of node, it's common to check both the Name and ArgCount(); checking both in one call avoids extra interface invocations.

Implements Loyc.Syntax.ILNode.

Reimplemented in Loyc.Syntax.CallNode.

Referenced by Loyc.LLParserGenerator.IntStreamCodeGenHelper.CodeToTerminalPred(), Loyc.Ecs.Parser.EcsTriviaInjector.DoneAttaching(), Loyc.Syntax.LNodeExt.GetCaptureIdentifier(), Loyc.LLParserGenerator.Rule.GetMethodSignature(), Loyc.Syntax.StandardTriviaInjector.HasImplicitLeadingNewline(), Loyc.Ecs.EcsValidators.IsVariableDeclExpr(), Loyc.Ecs.EcsValidators.KeyNameComponentOf(), Loyc.Syntax.LNode.MergeLists(), and Loyc.LLParserGenerator.CodeGenHelperBase.VisitInput().

◆ CallsMin() [1/2]

virtual bool Loyc.Syntax.LNode.CallsMin	(	string	name,
		int	minArgCount
	)

inlinevirtual

Returns true if this is a call with the specified name and the specified minimum number of arguments.

Reimplemented in Loyc.Syntax.CallNode.

◆ CallsMin() [2/2]

virtual bool Loyc.Syntax.LNode.CallsMin	(	Symbol	name,
		int	minArgCount
	)

inlinevirtual

Returns true if this is a call with the specified name and the specified minimum number of arguments.

Implements Loyc.Syntax.ILNode.

Reimplemented in Loyc.Syntax.CallNode.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.CallRule(), Loyc.Ecs.Parser.EcsTriviaInjector.DoneAttaching(), Loyc.Ecs.EcsValidators.IsIsTest(), Loyc.Ecs.EcsValidators.KeyNameComponentOf(), and Loyc.LLParserGenerator.CodeGenHelperBase.VisitInput().

◆ Clone()

abstract LNode Loyc.Syntax.LNode.Clone ( )

pure virtual

Creates a copy of the node. Since nodes are immutable, there is little reason for an end-user to call this, but Clone() is used internally as a helper method by the WithXyz() methods.

Implemented in Loyc.Syntax.CallNode, Loyc.Syntax.LiteralNode, and Loyc.Syntax.IdNode.

◆ Equals() [1/2]

virtual bool Loyc.Syntax.LNode.Equals	(	ILNode	other,
		CompareMode	mode
	)

inlinevirtual

Compares two nodes for structural equality. Two nodes are considered equal if they have the same kind, the same name, the same value, the same arguments, and the same attributes.

Parameters

mode	Whether to pay attention to Style and trivia attributes

Position information (Range) is not compared.

References Loyc.Syntax.LNode.Equals().

Referenced by Loyc.Syntax.LNode.Equals().

◆ Equals() [2/2]

static bool Loyc.Syntax.LNode.Equals	(	LNodeList	a,
		LNodeList	b,
		CompareMode	mode = `CompareMode.Normal`
	)

inlinestatic

Compares two lists of nodes for structural equality.

Parameters

mode	Whether to pay attention to Style and trivia attributes

Position information is not compared.

Referenced by Loyc.LLParserGenerator.GeneralCodeGenHelper.CodeToTerminalPred(), Loyc.Syntax.LNode.Equals(), and Loyc.LLParserGenerator.CodeGenHelperBase.VisitInput().

◆ FlattenBinaryOpSeq()

static List<LNode> Loyc.Syntax.LNode.FlattenBinaryOpSeq	(	LNode	expr,
		Symbol	opName,
		bool?	rightAssociative = `null`
	)

inlinestatic

Converts a sequence of the same operator (e.g. x+y+z) to a list (e.g. x, y, z).

Parameters

expr	An expression that may or may not call the operator.
opName	The operator to recognize.
rightAssociative	Whether the operator is right associative. If this is null then either or both associativities will work (e.g. `(ab)(c*d)` is flattened to a,b,c,d).

Returns: A list of subexpressions with the operator removed. If expr does not call the specified binary operator, the list contains a single item which is the original expression.

This is the reverse operation of MergeBinary.

◆ GetHashCode()

override int Loyc.Syntax.LNode.GetHashCode ( )

inline

Gets the hash code based on the structure of the tree.

If the tree is large, less than the entire tree is scanned to produce the hashcode (in the absolute worst case, about 4000 nodes are examined, but usually it is less than 100).

References Loyc.Syntax.LNode.GetHashCode().

Referenced by Loyc.Syntax.LNode.GetHashCode().

◆ HasSimpleHead()

virtual bool Loyc.Syntax.LNode.HasSimpleHead ( )

inlinevirtual

Returns true if this is not a call, or if the call's Target is an Id or a Literal.

Reimplemented in Loyc.Syntax.CallNode.

◆ HasSimpleHeadWithoutPAttrs()

virtual bool Loyc.Syntax.LNode.HasSimpleHeadWithoutPAttrs ( )

inlinevirtual

Returns true if this is not a call, or if the call's Target is an Id or a Literal, and the Target has only trivia attributes.

Reimplemented in Loyc.Syntax.CallNode.

◆ IsSpecialName()

static bool Loyc.Syntax.LNode.IsSpecialName ( string name )

inlinestatic

Returns true if name is considered a "special" name that starts with any character below 48 in ASCII, such as '#', '\'', and '.'.

This returns false for the empty string or null.

In order to keep the check trivially simple, this returns true for '$' even though it is not special in some languages (e.g. JavaScript).

Letters, underscores, digits, and some punctuation do not count as special. The full list of specials is ! " # $ % & ' ( ) * + , - . / plus the space character and the control characters.

◆ MergeBinary()

static LNode Loyc.Syntax.LNode.MergeBinary	(	LNode	node1,
		LNode	node2,
		Symbol	binaryOpName
	)

inlinestatic

Combines two nodes using a binary operator or function.

Parameters

node1	First node, list, or null.
node2	Second node, list, or null.
binaryOpName	Binary operator to use when the nodes are not null.

Returns: If either node1 or node2 is null, this method returns the other node (node1 ?? node2), otherwise the nodes are joined with the specified operator.

See also: FlattenBinaryOpSeq

References Loyc.Syntax.LNode.Range, and Loyc.Syntax.SourceRange.Source.

◆ MergeLists()

static LNode Loyc.Syntax.LNode.MergeLists	(	LNode	node1,
		LNode	node2,
		Symbol	listName
	)

inlinestatic

Some CallNodes are used to represent lists. This method merges two nodes, forming or appending a list (see remarks).

Parameters

node1	First node, list, or null.
node2	Second node, list, or null.
listName	The Name used to detect whether a node is a list (typically "#splice"). Any other name is considered a normal call, not a list. If this method creates a list from two non- lists, this parameter specifies the Name that the list will have.

Returns: The merged list.

The order of the data is retained (i.e. the data in node1 is inserted before the data in node2).

If either node1 or node2 is null, this method returns the other (node1 ?? node2).
If both node1 and node2 are lists, this method merges the list into a single list by appending node2's arguments at the end of node1. The attributes of node1 are kept and those of node2 are discarded.
If one of the nodes is a list and the other is not, the non-list is inserted into the list's Args.
If neither node is a list, a list is created with both nodes as its two Args.

See also: LNodeExt.WithSpliced

References Loyc.Syntax.LNode.Calls().

◆ PushPrinter()

static PushedPrinter Loyc.Syntax.LNode.PushPrinter ( ILNodePrinter printer )

inlinestatic

Helps you change printers temporarily. Usage in C#: using (LNode.PushPrinter(myPrinter)) { ... }

For example, to switch to the EC# printer, use using (LNode.PushPrinter(EcsNodePrinter.Printer)) { ... }. This changes the default printer. If you don't want to change the default printer, please invoke the printer directly:

var sb = new StringBuilder();

EcsNodePrinter.Printer(node, sb, MessageSink.Trace);

◆ ReplaceRecursive()

Maybe<LNode> Loyc.Syntax.LNode.ReplaceRecursive	(	Func< LNode, Maybe< LNode >>	matcher,
		ReplaceOpt	options = `ReplaceOpt.Default`
	)

inline

Performs a recursive find-and-replace operation, by attempting to replace each child (among Attrs, Target, Args) using the specified selector. This method can also be used for simple searching, by giving a selector that always returns null.

Parameters

matcher This method is called for each descendant, and optionally the root node. If the selector returns a node, the new node replaces the node that was passed to selector and the children of the new node are ignored. If the selector returns null, children of the child are scanned recursively. If the selector returns Maybe{LNode}.NoValue then the current node is deleted if it is an argument or attribute. If the current node is a target, it cannot be deleted, so it is replaced with #splice() which, by convention, represents an empty list. If you delete the root node then this method returns Maybe{LNode}.NoValue.

options Options, see ReplaceOpt.

Returns: The new node produced after all replacements have occurred.

If replaceFunc always returns null (or if replaceRoot is false and the root has no children), ReplaceRecursive returns this.

References Loyc.Syntax.LNode.Select().

◆ Select()

virtual LNode Loyc.Syntax.LNode.Select	(	Func< LNode, Maybe< LNode >>	selector,
		ReplaceOpt	options = `ReplaceOpt.ProcessAttrs`
	)

inlinevirtual

Transforms the Target, parameters, and optionally the attributes of an LNode, returning another LNode of the same Kind. If the selector makes no changes, Select() returns this.

The selector is not allowed to return null, but it can return NoValue.Value to delete a parameter or target. If the current node is a target, it cannot be deleted, so it is replaced with #splice() which, by convention, represents an empty list. If you're wondering why we don't use null for deletions, it is because the functionality of this method is actually implemented by VList<T>.WhereSelect(Func<T, Maybe<T>>); since T could be a value type, that method cannot use null as a signal to delete items from the collection.

It is not possible to delete the Target of a call, and if the selector returns NoValue.Value for the Target, the target is replaced with an empty call to #splice().

Reimplemented in Loyc.Syntax.CallNode.

Referenced by Loyc.Syntax.LNode.ReplaceRecursive().

◆ With() [1/2]

virtual CallNode Loyc.Syntax.LNode.With	(	LNode	target,
		LNodeList	args
	)

inlinevirtual

Creates a CallNode with the same attributes and Range, but a different target and argument list. If the current node is not a CallNode, it becomes one (the Range, Style and attributes of the current node are kept, but the Kind, Value, and Name are discarded.)

References Loyc.Syntax.LNode.Args, Loyc.Syntax.LNode.Attrs, and Loyc.Syntax.LNode.Target.

Referenced by Loyc.Syntax.CallNode.Select(), and Loyc.Syntax.CallNode.WithArgs().

◆ With() [2/2]

virtual CallNode Loyc.Syntax.LNode.With	(	Symbol	target,
		LNodeList	args
	)

inlinevirtual

Creates a CallNode with the same attributes and Range, but a different target and argument list. If the current node is not a CallNode, it becomes one (the Range, Style and attributes of the current node are kept, but the Kind, Value, and Name are discarded.)

References Loyc.Syntax.LNode.Attrs.

◆ WithArgs()

abstract CallNode Loyc.Syntax.LNode.WithArgs ( LNodeList args )

pure virtual

Creates a Node with a new argument list. If this node is not a call, a new node is created using this node as its target. Otherwise, the existing argument list is replaced.

Parameters

args	New argument list

Implemented in Loyc.Syntax.CallNode, Loyc.Syntax.LiteralNode, and Loyc.Syntax.IdNode.

Referenced by Loyc.LLParserGenerator.Rule.CreateMethod(), Loyc.LLParserGenerator.CodeGenHelperBase.CreateTryWrapperForRecognizer(), and Loyc.LLParserGenerator.Rule.GetMethodSignature().

◆ WithName()

virtual LNode Loyc.Syntax.LNode.WithName ( Symbol name )

inlinevirtual

Creates a node with a new value for Name.

If IsId, the Name is simply changed. If IsCall, this method returns the equivalent of WithTarget(Target.WithName(name)) (which may be optimized for the particular call type). If IsLiteral, the Kind changes to LNodeKind.Id in order to set the name.

Reimplemented in Loyc.Syntax.CallNode, and Loyc.Syntax.IdNode.

References Loyc.Syntax.LNode.Attrs.

Referenced by Loyc.Syntax.CallNode.WithName().

◆ WithValue()

abstract LiteralNode Loyc.Syntax.LNode.WithValue ( object value )

pure virtual

Creates a new literal node with a different Value than the current literal node.

Exceptions

InvalidOperationException The node was not a literal already.

Implemented in Loyc.Syntax.CallNode, Loyc.Syntax.LiteralNode, and Loyc.Syntax.IdNode.

Member Data Documentation

◆ InParensTrivia

readonly LNode Loyc.Syntax.LNode.InParensTrivia = Id(CodeSymbols.TriviaInParens)

static

Used by the quote {...} macro.

◆ Missing

readonly IdNode Loyc.Syntax.LNode.Missing = Id(CodeSymbols.Missing)

static

The empty identifier, used to represent missing information.

Referenced by Loyc.LLPG.Macros.LLLPG_lexer(), and Loyc.LLPG.Macros.LLLPG_parser().

◆ TextValue

virtual UString Loyc.Syntax.LNode.TextValue => default(UString)

If this node IsLiteral, gets the original text of the literal, if it is available. This property is empty if the node was created programmatically from a value, or if the parser did not save the original text, or if this is not a literal.

If you need a string version of the value, call ToString() on it.

◆ TypeMarker

virtual Symbol Loyc.Syntax.LNode.TypeMarker => null

If this node IsLiteral, gets the type marker associated with the literal. This property is null if the node was created programmatically from a value, or if the parser did not save the type marker, or if this is not a literal.

Property Documentation

◆ Args

abstract LNodeList Loyc.Syntax.LNode.Args

get

Returns the argument list of this node. Always empty when IsCall==false.

Depending on the Target, Args may represent an actual argument list, or it may represent some other kind of list. For example, if the target is "{}" then Args represents a list of statements in a braced block, and if the target is ">=" then Args represents the two arguments to the ">=" operator.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.CallRule(), Loyc.LLParserGenerator.IntStreamCodeGenHelper.CodeToTerminalPred(), Loyc.LLParserGenerator.Rule.CreateMethod(), Loyc.LLParserGenerator.CodeGenHelperBase.CreateTryWrapperForRecognizer(), Loyc.Ecs.Parser.EcsTriviaInjector.DoneAttaching(), LeMP.MacroContext.GetArgsAndBody(), Loyc.Syntax.LNodeExt.GetCaptureIdentifier(), Loyc.LLParserGenerator.Rule.GetMethodSignature(), LeMP.MacroContext.GetOptions(), Loyc.Ecs.EcsValidators.IsIsTest(), Loyc.Ecs.EcsValidators.IsPropertyDefinition(), Loyc.Ecs.EcsValidators.IsVariableDeclExpr(), Loyc.Ecs.EcsValidators.KeyNameComponentOf(), Loyc.LLPG.Macros.LllpgMacro(), Loyc.Syntax.LNodeExt.MatchesPattern(), Loyc.Ecs.EcsValidators.MethodDefinitionKind(), Loyc.Ecs.EcsValidators.SpaceDefinitionKind(), Loyc.LLParserGenerator.CodeGenHelperBase.VisitInput(), and Loyc.Syntax.LNode.With().

◆ Attrs

virtual LNodeList Loyc.Syntax.LNode.Attrs

get

Returns the attribute list for this node.

Referenced by Loyc.Syntax.LNodeExt.GetTrailingTrivia(), Loyc.Ecs.EcsValidators.IsPrintableTypeParam(), Loyc.Syntax.LNodeExt.PlusTrailingTrivia(), Loyc.Syntax.LNodeExt.Unsplice(), Loyc.Syntax.LNode.With(), Loyc.Syntax.LNode.WithName(), and Loyc.Syntax.LNodeExt.WithTrailingTrivia().

◆ HasSpecialName

bool Loyc.Syntax.LNode.HasSpecialName

get

Returns true if Name is a "special" name (i.e. starts with '#' or '\'' or '.' or any character below 48 in ASCII).

Note that this property returns false for the empty identifier @``.

◆ IsFrozen

virtual bool Loyc.Syntax.LNode.IsFrozen

get

Returns true if the node is immutable, and false if any part of it can be edited. Currently, mutable nodes are not implemented.

Debugger-hidden until such time as mutable nodes actually exist.

◆ Kind

abstract LNodeKind Loyc.Syntax.LNode.Kind

get

Returns the LNodeKind: Symbol, Literal, or Call.

Referenced by Loyc.Syntax.LNodeExt.MatchesPattern().

◆ Name

abstract Symbol Loyc.Syntax.LNode.Name

get

Returns the Symbol if IsId. If this node is a call (IsCall) and Target.IsId is true, this property returns Target.Name. In all other cases, the name is GSymbol.Empty. Shall not return null.

Examples (using C#/LES syntax):

Expression   Kind    Name (blank if empty)
hello        Id      hello
#if         Id      #if
Foo(x, y)    Call    Foo
x += y       Call    +=
x.Foo(y)     Call    
5.0          Literal

Referenced by Loyc.LLParserGenerator.GeneralCodeGenHelper.CodeToTerminalPred(), Loyc.Ecs.EcsValidators.KeyNameComponentOf(), Loyc.Syntax.LNodeExt.MatchesPattern(), Loyc.Ecs.EcsValidators.MethodDefinitionKind(), and Loyc.Ecs.EcsValidators.SpaceDefinitionKind().

◆ Printer

ILNodePrinter?? Loyc.Syntax.LNode.Printer

staticgetset

Gets or sets the default node printer on the current thread, which controls how nodes are serialized to text by default.

The LES printer is the default, and will be used if you try to set this property to null.

◆ Range

virtual SourceRange Loyc.Syntax.LNode.Range

get

Returns the location and range in source code of this node.

A parser should record a sufficiently wide range for each parent node, such that all children are fully contained within the range. However, this is not an invariant; macros can splice together syntax trees from different source files or add synthetic nodes, so that the parent range does not necessarily include all child ranges. (In fact, in general it is impossible to ensure that parent ranges include child ranges because a parent can only specify a single source file, while children can come from several source files.)

Referenced by Loyc.Syntax.LNodeExt.AsLNode(), Loyc.Ecs.Parser.EcsTriviaInjector.DoneAttaching(), Loyc.Syntax.LNode.MergeBinary(), Loyc.Syntax.AbstractTriviaInjector< Token >.RunCore(), Loyc.Syntax.IdNode.WithArgs(), and Loyc.Syntax.LiteralNode.WithArgs().

◆ Source

ISourceFile Loyc.Syntax.LNode.Source

get

Returns the source file (shortcut for Range.Source).

◆ Style

NodeStyle Loyc.Syntax.LNode.Style

getset

Indicates the preferred style to use when printing the node to a text string.

The Style is an 8-bit value that acts as a hint to the node printer about how the node should be printed. Custom display styles that do not fit in the Style property can be expressed with special "trivia" attributes that have a Name starting with %. (trivia attributes, which are also used to store comments in the syntax tree, are not printed like normal attributes and are normally ignored if the node printer does not specifically recognize them.)

◆ Target

abstract LNode Loyc.Syntax.LNode.Target

get

Returns the target of a method call, or null if IsCall is false. The target can be a symbol with no name (GSymbol.Empty) to represent a parenthesized expression, if there is one argument.

Referenced by Loyc.Ecs.Parser.EcsTriviaInjector.DoneAttaching(), Loyc.Ecs.EcsValidators.KeyNameComponentOf(), Loyc.Syntax.LNodeExt.MatchesPattern(), Loyc.Syntax.CallNode.Select(), and Loyc.Syntax.LNode.With().

◆ TriviaValue

virtual object Loyc.Syntax.LNode.TriviaValue

get

Gets the value of Args[0].Value, if Args[0] exists; otherwise, returns NoValue.Value.

"Trivia nodes" are used to efficiently represent the value of trivia and non-tree Lexing.Tokens; they can be created by calling the LNode.Trivia function. Since an LNode is not allowed to have both a Name and a Value (as there is no syntax in LES or EC# for such a node), a trivia node pretends that there is an argument list with one item, and that one item is always a literal whose Value is the value stored in the trivia node. Thus, a token node is printed out as TokenType(Value) where Value is some literal.

If you suspect you're dealing with a trivia node, it is wasteful to actually call node.Args[0].Value since this causes a temporary token list to be allocated. Instead you should use this property, which returns the token value without allocating memory. Of course, if this property is called on a non-trivia node, it simply returns Args[0].Value.

◆ Value

abstract object Loyc.Syntax.LNode.Value

get

Returns the value of a literal node, or NoValue.Value if this node is not a literal (IsLiteral is false).

Referenced by Loyc.LLParserGenerator.IntStreamCodeGenHelper.CodeToTerminalPred(), Loyc.LLPG.Macros.LLLPG_lexer(), Loyc.LLPG.Macros.LLLPG_parser(), Loyc.LLPG.Macros.LllpgMacro(), and Loyc.Syntax.LNodeExt.MatchesPattern().

Remarks

Important properties

Nested classes

Public Types

Public fields

Public static fields

Properties

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected fields

Protected static fields

Member Enumeration Documentation

◆ ReplaceOpt

Member Function Documentation

◆ Calls()

◆ CallsMin() [1/2]

◆ CallsMin() [2/2]

◆ Clone()

◆ Equals() [1/2]

◆ Equals() [2/2]

◆ FlattenBinaryOpSeq()

◆ GetHashCode()

◆ HasSimpleHead()

◆ HasSimpleHeadWithoutPAttrs()

◆ IsSpecialName()

◆ MergeBinary()

◆ MergeLists()

◆ PushPrinter()

◆ ReplaceRecursive()

◆ Select()

◆ With() [1/2]

◆ With() [2/2]

◆ WithArgs()

◆ WithName()

◆ WithValue()

Member Data Documentation

◆ InParensTrivia

◆ Missing

◆ TextValue

◆ TypeMarker

Property Documentation

◆ Args

◆ Attrs

◆ HasSpecialName

◆ IsFrozen

◆ Kind

◆ Name

◆ Printer

◆ Range

◆ Source

◆ Style

◆ Target

◆ TriviaValue

◆ Value