Suggested base class for custom code generators. Each derived class is typically designed for a different kind of token. More...

Source file:

/Main/LLLPG/CodeGenHelpers/CodeGenHelperBase.cs

Inheritance diagram for Loyc.LLParserGenerator.CodeGenHelperBase:

Remarks

Suggested base class for custom code generators. Each derived class is typically designed for a different kind of token.

LLPG comes with two derived classes, IntStreamCodeGenHelper for parsing input streams of characters or integers, and GeneralCodeGenHelper for parsing other streams. This class contains common code used by both, for example:

default code snippets such as LA0 and LA(n), the default error branch, and switch statements;
the decision function ShouldGenerateSwitch(); and
alias handling (alias "foo" = bar); note that the derived class's NodeToPred() method is responsible for using _definedAliases.

Properties
LNode	InputSource `[get, set]`
	Specifies an object or class on which LLLPG APIs such as Match() and LA() should be called. More...

LNode	InputClass `[get, set]`
	Specifies a class or namespace to use when calling static functions. There is only one currently: NewSet(), which applies only to . More...

LNode	TerminalType `[get, set]`
	The type returned from Match() methods. More...

LNode	ListType `[get, set]`
	Gets or sets the type of lists created with the +: operator (default: List<T>). The identifier "T" should appear in the expression; it will be replaced with the type of items in the list. More...

LNode	ListInitializer `[get, set]`
	Gets or sets the initializer expression for lists created with the +: operator (default: new List<T>()). The identifier "T" should appear in the expression; it will be replaced with the type of items in the list. More...

bool	NoCheckByDefault `[get, set]`
	If true, calls to `Check()` are suppressed when AndPred.CheckErrorMessage is null. More...

abstract IPGTerminalSet	EmptySet `[get]`

Properties inherited from Loyc.LLParserGenerator.IPGCodeGenHelper
IPGTerminalSet	EmptySet `[get]`
	Returns an empty set of the appropriate type for the kind of parser being generated by this code. More...

LNode	TerminalType `[get]`
	Type of variables auto-declared when you use labels in your grammar (e.g. x:Foo (list+:Bar)*) More...

Public Member Functions
void	SetListInitializer (LNode varDecl)
	Sets ListType and/or ListInitializer based on an expression. A statement like `Type x = expr` sets `ListType = Type` and `ListInitializer = expr`; A statement like `Type x` just sets `ListType = Type`; and any other expression `expr` sets `ListInitializer = expr`. More...

LNode	ResolveAlias (LNode expr)
	Returns the node for an alias. If the specified node is not an alias, returns the same node unchanged. More...

virtual LNode	VisitInput (LNode stmt, IMessageSink sink)
	In case the IPGCodeGenHelper is interested, the LLLPG macro calls this method on each statement in the body of the macro (as a preprocessing step, before LLLPG looks at it). No action is required. More...

abstract Pred	CodeToTerminalPred (LNode expr, ref string errorMsg)
	Creates a terminal predicate from a code expression. More...

virtual IPGTerminalSet	Optimize (IPGTerminalSet set, IPGTerminalSet dontcare)
	Simplifies the specified set, if possible, so that GenerateTest() can generate simpler code for an if-else chain in a prediction tree. More...

virtual ? char	ExampleChar (IPGTerminalSet set)
	Returns an example of a character in the set, or null if this is not a set of characters or if EOF is the only member of the set. More...

abstract string	Example (IPGTerminalSet set)
	Returns an example of an item in the set. If the example is a character, it should be surrounded by single quotes. More...

virtual void	Begin (WList< LNode > classBody, ISourceFile sourceFile)
	Before the parser generator generates code, it calls this method. More...

virtual void	BeginRule (Rule rule)
	Notifies the snippet generator that code generation is starting for a new rule. More...

virtual void	Done ()
	LLParserGenerator calls this method to notify the snippet generator that code generation is complete. More...

virtual LNode	GenerateTest (IPGTerminalSet set, LNode laVar)
	Generates code to test whether the terminal denoted 'laVar' is in the set. More...

virtual LNode	GenerateSkip (bool savingResult)
	Returns `(Skip())`, or `(MatchAny())` if the result is to be saved. More...

virtual LNode	GenerateAndPredCheck (AndPred andPred, LNode code, int li)
	Generate code to check an and-predicate during or after prediction, e.g. &!{foo} becomes !(foo) during prediction and Check(!(foo)); afterward. More...

virtual LNode	GenerateMatch (IPGTerminalSet set, bool savingResult, bool recognizerMode)
	Generate code to match a set, e.g. `MatchRange('a', 'z');` or `MatchExcept(' ', '\r'); }`. If the set is too complex, a declaration for it is created in the `classBody` which was passed to `Begin()`. More...

Public Member Functions inherited from Loyc.LLParserGenerator.IPGCodeGenHelper

Protected Member Functions
abstract LNode	GenerateTest (IPGTerminalSet set, LNode subject, Symbol setName)
	Generates code to test whether a terminal is in the set. More...

virtual Symbol	GenerateSetName (Rule currentRule)

virtual Symbol	GenerateSetDecl (IPGTerminalSet set)

abstract LNode	GenerateSetDecl (IPGTerminalSet set, Symbol setName)
	Generates a declaration for a variable that holds the set. More...

Protected fields
int	_setNameCounter = 0

LNodeFactory	F

WList< LNode >	_classBody

Rule	_currentRule

Dictionary< LNode, LNode >	_definedAliases = new Dictionary<LNode, LNode>()

Protected static fields
static readonly Symbol	_Skip = GSymbol.Get("Skip")

static readonly Symbol	_MatchAny = GSymbol.Get("MatchAny")

static readonly Symbol	_Match = GSymbol.Get("Match")

static readonly Symbol	_MatchExcept = GSymbol.Get("MatchExcept")

static readonly Symbol	_MatchRange = GSymbol.Get("MatchRange")

static readonly Symbol	_MatchExceptRange = GSymbol.Get("MatchExceptRange")

static readonly Symbol	_TryMatch = GSymbol.Get("TryMatch")

static readonly Symbol	_TryMatchExcept = GSymbol.Get("TryMatchExcept")

static readonly Symbol	_TryMatchRange = GSymbol.Get("TryMatchRange")

static readonly Symbol	_TryMatchExceptRange = GSymbol.Get("TryMatchExceptRange")

static readonly Symbol	_LA = GSymbol.Get("LA")

static readonly Symbol	_LA0 = GSymbol.Get("LA0")

static readonly Symbol	_Check = GSymbol.Get("Check")

static readonly Symbol	_Error = GSymbol.Get("Error")

static readonly Symbol	_underscore = GSymbol.Get("_")

static readonly Symbol	_alias = GSymbol.Get("alias")

static readonly Symbol	_T = GSymbol.Get("T")

virtual int	BaseCostForSwitch `[get]`
	Used to help decide whether a "switch" or an if-else chain will be used for prediction. This is the starting cost of a switch (the starting cost of an if-else chain is set to zero). More...

abstract LNode	GenerateMatchExpr (IPGTerminalSet set, bool savingResult, bool recognizerMode)
	Generate code to match a set, e.g. `MatchRange('a', 'z');` or `MatchExcept(' ', '\r'); }`. If the set is too complex, a declaration for it is created in classBody. More...

virtual LNode	LA (int k)
	Generates code to read LA(k). More...

virtual LNode	ErrorBranch (IPGTerminalSet covered, int laIndex)
	Generates code for the default error branch of prediction (called when there is no explicit error branch). More...

abstract LNode	LAType ()
	Returns the data type of LA(k) More...

virtual bool	ShouldGenerateSwitch (IPGTerminalSet[] sets, MSet< int > casesToInclude, bool hasErrorBranch)
	Decides whether to use a switch() and for which cases, using BaseCostForSwitch and GetRelativeCostForSwitch. More...

virtual LNode	GenerateSwitch (IPGTerminalSet[] branchSets, LNode[] branchCode, MSet< int > casesToInclude, LNode defaultBranch, LNode laVar)
	Generates a switch statement with the specified branches where branchCode[i] is the code to run if the input is in the set branchSets[i]. More...

virtual LNode	CreateRuleMethod (Rule rule, LNodeList methodBody)
	Generates the method for a rule, given the method's contents. More...

LNode	CreateTryWrapperForRecognizer (Rule rule)
	See IPGCodeGenHelper.CreateTryWrapperForRecognizer for more information. More...

virtual LNode	CallRule (RuleRef rref, bool recognizerMode)
	Generates code to call a rule based on `rref.Rule.Name` and `rref.Params`. More...

virtual LNode	CallTryRecognizer (RuleRef rref, int lookahead)
	Generates a call to the Try_Scan_() function that wraps around a Scan_() recognizer. Called while generating code for an and-pred. More...

virtual LNode	GetListType (LNode type)
	Gets the list type for elements of the specified type (e.g. List<type>) More...

virtual LNode	MakeInitializedVarDecl (LNode type, bool wantList, Symbol varName)
	Gets a variable declaration for the specified type, e.g. if type is `Foo` and `wantList == true` and `varName.Name == "x"`, the statement returned might be `List<Foo> x = new List<Foo>();` More...

virtual int	GetRelativeCostForSwitch (IPGTerminalSet set)
	Used to help decide whether a "switch" or an if statement will be used to handle a prediction tree, and if so which branches. This method should calculate the "cost of switch" (which generally represents a code size penalty, as there is a separate case for every element of the set) and the "cost of if" (which generally represents a speed penalty) and return the difference (so that positive numbers favor "switch" and negative numbers favor "if".) More...

virtual IEnumerable< LNode >	GetCases (IPGTerminalSet set)
	Gets the literals or symbols to use for switch cases of a set (just the values, not including the case labels.) More...

virtual LNode	ApiCall (Symbol apiName, params LNode[] args)
	Returns an LNode representing a call to the specified LLLPG API. For example, if the user used a "inputSource=input" option, then `ApiCall(_Match, F.Literal('7'))` would generate a node that represents `input.Match('7')`. More...

virtual LNode	ApiCall (Symbol apiName, IEnumerable< LNode > args, bool isStatic=false)
	Returns an LNode representing a call to the specified LLLPG API. For example, if the user used a "inputSource=input" option, then `ApiCall(_Match, F.Literal('7'))` would generate a node that represents `input.Match('7')`. More...

virtual LNode	ApiType (LNode typeName)

virtual LNode	DefaultOf (LNode type, bool wantList)

static bool	EndMayBeReachable (LNode stmt)

Member Function Documentation

◆ ApiCall() [1/2]

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall	(	Symbol	apiName,
		IEnumerable< LNode >	args,
		bool	isStatic = `false`
	)

inlineprotectedvirtual

Returns an LNode representing a call to the specified LLLPG API. For example, if the user used a "inputSource=input" option, then ApiCall(_Match, F.Literal('7')) would generate a node that represents input.Match('7').

Parameters

args	Parameters to the API call, or null to access a property or field.

References Loyc.LLParserGenerator.CodeGenHelperBase.InputClass, and Loyc.LLParserGenerator.CodeGenHelperBase.InputSource.

◆ ApiCall() [2/2]

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall	(	Symbol	apiName,
		params LNode[]	args
	)

inlineprotectedvirtual

Returns an LNode representing a call to the specified LLLPG API. For example, if the user used a "inputSource=input" option, then ApiCall(_Match, F.Literal('7')) would generate a node that represents input.Match('7').

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.ErrorBranch(), Loyc.LLParserGenerator.CodeGenHelperBase.GenerateAndPredCheck(), Loyc.LLParserGenerator.IntStreamCodeGenHelper.GenerateMatchExpr(), Loyc.LLParserGenerator.GeneralCodeGenHelper.GenerateMatchExpr(), Loyc.LLParserGenerator.CodeGenHelperBase.GenerateSkip(), and Loyc.LLParserGenerator.CodeGenHelperBase.LA().

◆ Begin()

virtual void Loyc.LLParserGenerator.CodeGenHelperBase.Begin	(	WList< LNode >	classBody,
		ISourceFile	sourceFile
	)

inlinevirtual

Before the parser generator generates code, it calls this method.

Parameters

classBody	the body (braced block) of the class where the code will be generated, which allows the snippet generator to add code at class level when needed.
sourceFile	the suggested ISourceFile to assign to generated code snippets.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

◆ BeginRule()

virtual void Loyc.LLParserGenerator.CodeGenHelperBase.BeginRule ( Rule rule )

inlinevirtual

Notifies the snippet generator that code generation is starting for a new rule.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

◆ CallRule()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.CallRule	(	RuleRef	rref,
		bool	recognizerMode
	)

inlinevirtual

Generates code to call a rule based on rref.Rule.Name and rref.Params.

Returns

For a normal rule call, this method should return rref.AutoSaveResult(code) where code is the code to invoke the rule.

Recognizer mode is normally implemented by calling the recognizer version of the rule in an "if" statement: if (!Scan_Foo()) return false;

Backtrack mode expects a boolean expression to be returned, normally something like Try_Scan_Foo() where the name Try_Is_Foo comes from the recognizer's Rule.TryWrapperName.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.Syntax.LNode.Args, Loyc.LLParserGenerator.Rule.Basis, Loyc.Syntax.LNode.CallsMin(), Loyc.Syntax.CodeSymbols.If, Loyc.Syntax.CodeSymbols.Not, and Loyc.Syntax.CodeSymbols.Return.

◆ CallTryRecognizer()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.CallTryRecognizer	(	RuleRef	rref,
		int	lookahead
	)

inlinevirtual

Generates a call to the Try_Scan_*() function that wraps around a Scan_*() recognizer. Called while generating code for an and-pred.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

◆ CodeToTerminalPred()

abstract Pred Loyc.LLParserGenerator.CodeGenHelperBase.CodeToTerminalPred	(	LNode	expr,
		ref string	errorMsg
	)

pure virtual

Creates a terminal predicate from a code expression.

Parameters

expr	A expression provided by the user, such as `"a string"`, a `Token.Type`, or a `value..range`. `expr` will not be a call to the inversion operator #~ (that's handled internally using IPGTerminalSet.Inverted()). This method also handles the "any token" input, which is an underscore by convention (_).
errorMsg	An error message to display. If the method returns null, the LLLPG macro shows this as an error; if this method does not return null, the message (if provided) is shown as a warning.

Returns: If successful, a terminal predicate; otherwise null.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Implemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ CreateRuleMethod()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.CreateRuleMethod	(	Rule	rule,
		LNodeList	methodBody
	)

inlinevirtual

Generates the method for a rule, given the method's contents.

Parameters

rule	Rule for which a method is needed.
methodBody	A list of statements produced by LLParserGenerator inside the method.

Returns: A method definition for the rule.

To generate the default method, simply call Rule.CreateMethod(VList<LNode>).

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.Rule.CreateMethod().

◆ CreateTryWrapperForRecognizer()

LNode Loyc.LLParserGenerator.CodeGenHelperBase.CreateTryWrapperForRecognizer ( Rule rule )

inline

See IPGCodeGenHelper.CreateTryWrapperForRecognizer for more information.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.Syntax.CodeSymbols.AltList, Loyc.Syntax.LNode.Args, Loyc.LLParserGenerator.Rule.GetMethodSignature(), Loyc.LLParserGenerator.CodeGenHelperBase.InputSource, Loyc.Syntax.CodeSymbols.New, Loyc.Syntax.CodeSymbols.Return, Loyc.Syntax.CodeSymbols.UsingStmt, and Loyc.Syntax.LNode.WithArgs().

◆ Done()

virtual void Loyc.LLParserGenerator.CodeGenHelperBase.Done ( )

inlinevirtual

LLParserGenerator calls this method to notify the snippet generator that code generation is complete.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

◆ ErrorBranch()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.ErrorBranch	(	IPGTerminalSet	covered,
		int	laIndex
	)

inlinevirtual

Generates code for the default error branch of prediction (called when there is no explicit error branch).

Parameters

covered	The permitted token set, which the input did not match. NOTE: if the input matched but there were and-predicates that did not match, this parameter will be null (e.g. the input is 'b' in `(&{x} 'a' \| &{y} 'b')`, but y is false.
laIndex	Location of unexpected input, relative to current position.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall(), and Loyc.Symbol.Name.

◆ Example()

abstract string Loyc.LLParserGenerator.CodeGenHelperBase.Example ( IPGTerminalSet set )

pure virtual

Returns an example of an item in the set. If the example is a character, it should be surrounded by single quotes.

This helps produce error messages in LLLPG.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Implemented in Loyc.LLParserGenerator.IntStreamCodeGenHelper, and Loyc.LLParserGenerator.GeneralCodeGenHelper.

◆ ExampleChar()

virtual ? char Loyc.LLParserGenerator.CodeGenHelperBase.ExampleChar ( IPGTerminalSet set )

inlinevirtual

Returns an example of a character in the set, or null if this is not a set of characters or if EOF is the only member of the set.

This helps produce error messages in LLLPG.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Reimplemented in Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ GenerateAndPredCheck()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateAndPredCheck	(	AndPred	andPred,
		LNode	code,
		int	li
	)

inlinevirtual

Generate code to check an and-predicate during or after prediction, e.g. &!{foo} becomes !(foo) during prediction and Check(!(foo)); afterward.

Parameters

andPred	Predicate for which an expression has already been generated
code	The expression to be checked
li	Current lookahead amount. -1 means "prediction is complete, generate a Check() statement".

LLLPG substitutes $LI and $LA before it calls this method. This method can return null to suppress the Check statement.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall(), Loyc.LLParserGenerator.AndPred.CheckErrorMessage, Loyc.Syntax.ParsingMode.Expressions, Loyc.Syntax.CodeSymbols.If, Loyc.LLParserGenerator.CodeGenHelperBase.NoCheckByDefault, Loyc.Syntax.CodeSymbols.Not, Loyc.LLParserGenerator.AndPred.Not, Loyc.LLParserGenerator.AndPred.Pred, and Loyc.Syntax.CodeSymbols.Return.

◆ GenerateMatch()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateMatch	(	IPGTerminalSet	set_,
		bool	savingResult,
		bool	recognizerMode
	)

inlinevirtual

Generate code to match a set, e.g. MatchRange('a', 'z'); or MatchExcept(' ', '\r'); }. If the set is too complex, a declaration for it is created in the classBody which was passed to Begin().

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.GenerateMatchExpr(), Loyc.Syntax.CodeSymbols.If, Loyc.Syntax.CodeSymbols.Not, and Loyc.Syntax.CodeSymbols.Return.

◆ GenerateMatchExpr()

abstract LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateMatchExpr	(	IPGTerminalSet	set,
		bool	savingResult,
		bool	recognizerMode
	)

pure virtual

Generate code to match a set, e.g. MatchRange('a', 'z'); or MatchExcept(' ', '\r'); }. If the set is too complex, a declaration for it is created in classBody.

Implemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.GenerateMatch().

◆ GenerateSetDecl()

abstract LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateSetDecl	(	IPGTerminalSet	set,
		Symbol	setName
	)

protectedpure virtual

Generates a declaration for a variable that holds the set.

For example, if setName is foo, a set such as [aeiouy] might use an external declaration such as

HashSet<int> foo = NewSet('a', 'e', 'i', 'o', 'u', 'y');

Implemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ GenerateSkip()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateSkip ( bool savingResult )

inlinevirtual

Returns (Skip()), or (MatchAny()) if the result is to be saved.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall().

◆ GenerateSwitch()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateSwitch	(	IPGTerminalSet[]	branchSets,
		LNode[]	branchCode,
		MSet< int >	casesToInclude,
		LNode	defaultBranch,
		LNode	laVar
	)

inlinevirtual

Generates a switch statement with the specified branches where branchCode[i] is the code to run if the input is in the set branchSets[i].

Parameters

casesToInclude	The set chosen by ShouldGenerateSwitch.
defaultBranch	Code to be placed in the default: case, or the empty identifier (@``) if none
laVar	The lookahead variable being switched on (e.g. la0)

Returns: The generated switch block.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.Syntax.CodeSymbols.Case, Loyc.Syntax.CodeSymbols.Default, Loyc.LLParserGenerator.CodeGenHelperBase.GetCases(), Loyc.Syntax.CodeSymbols.Label, and Loyc.Syntax.CodeSymbols.SwitchStmt.

◆ GenerateTest() [1/2]

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateTest	(	IPGTerminalSet	set,
		LNode	laVar
	)

inlinevirtual

Generates code to test whether the terminal denoted 'laVar' is in the set.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

◆ GenerateTest() [2/2]

abstract LNode Loyc.LLParserGenerator.CodeGenHelperBase.GenerateTest	(	IPGTerminalSet	set,
		LNode	subject,
		Symbol	setName
	)

protectedpure virtual

Generates code to test whether a terminal is in the set.

Parameters

subject	Represents the variable to be tested.
setName	Names an external set variable to use for the test.

Returns: A test expression such as (la0 >= '0' && '9' >= la0), or null if an external setName is needed and was not provided.

At first, LLParserGenerator calls this method with setName == null. If it returns null, it calls the method a second time, giving the name of an external variable in which the set is held (see GenerateSetDecl(IPGTerminalSet)).

For example, if the subject is @la0, the test for a simple set like [a-z?] might be something like (la0 >= 'a' && 'z' >= la0) || la0 == '?'. When the setName is foo, the test might be foo.Contains(la0) instead.

Implemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ GetCases()

virtual IEnumerable<LNode> Loyc.LLParserGenerator.CodeGenHelperBase.GetCases ( IPGTerminalSet set )

inlineprotectedvirtual

Gets the literals or symbols to use for switch cases of a set (just the values, not including the case labels.)

Reimplemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.GenerateSwitch().

◆ GetListType()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.GetListType ( LNode type )

inlinevirtual

Gets the list type for elements of the specified type (e.g. List<type>)

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.ListType.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.MakeInitializedVarDecl().

◆ GetRelativeCostForSwitch()

virtual int Loyc.LLParserGenerator.CodeGenHelperBase.GetRelativeCostForSwitch ( IPGTerminalSet set )

inlineprotectedvirtual

Used to help decide whether a "switch" or an if statement will be used to handle a prediction tree, and if so which branches. This method should calculate the "cost of switch" (which generally represents a code size penalty, as there is a separate case for every element of the set) and the "cost of if" (which generally represents a speed penalty) and return the difference (so that positive numbers favor "switch" and negative numbers favor "if".)

If the set is inverted, return a something like -1000000 to ensure 'switch' is not used for that set.

Reimplemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.ShouldGenerateSwitch().

◆ LA()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.LA ( int k )

inlinevirtual

Generates code to read LA(k).

Returns: Default implementation returns LA0 for k==0, LA(k) otherwise.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Reimplemented in Loyc.LLParserGenerator.GeneralCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall().

◆ LAType()

abstract LNode Loyc.LLParserGenerator.CodeGenHelperBase.LAType ( )

pure virtual

Returns the data type of LA(k)

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Implemented in Loyc.LLParserGenerator.GeneralCodeGenHelper, and Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ MakeInitializedVarDecl()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.MakeInitializedVarDecl	(	LNode	type,
		bool	wantList,
		Symbol	varName
	)

inlinevirtual

Gets a variable declaration for the specified type, e.g. if type is Foo and wantList == true and varName.Name == "x", the statement returned might be List<Foo> x = new List<Foo>();

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.LLParserGenerator.CodeGenHelperBase.GetListType().

◆ Optimize()

virtual IPGTerminalSet Loyc.LLParserGenerator.CodeGenHelperBase.Optimize	(	IPGTerminalSet	set,
		IPGTerminalSet	dontcare
	)

inlinevirtual

Simplifies the specified set, if possible, so that GenerateTest() can generate simpler code for an if-else chain in a prediction tree.

Parameters

set
dontcare	A set of terminals that have been ruled out, i.e. it is already known that the lookahead value is not in this set.

Returns: An optimized set, or this.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Reimplemented in Loyc.LLParserGenerator.IntStreamCodeGenHelper.

◆ ResolveAlias()

LNode Loyc.LLParserGenerator.CodeGenHelperBase.ResolveAlias ( LNode node )

inline

Returns the node for an alias. If the specified node is not an alias, returns the same node unchanged.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

Referenced by Loyc.LLParserGenerator.GeneralCodeGenHelper.CodeToTerminalPred().

◆ SetListInitializer()

void Loyc.LLParserGenerator.CodeGenHelperBase.SetListInitializer ( LNode varDecl )

inline

Sets ListType and/or ListInitializer based on an expression. A statement like Type x = expr sets ListType = Type and ListInitializer = expr; A statement like Type x just sets ListType = Type; and any other expression expr sets ListInitializer = expr.

References Loyc.LLParserGenerator.CodeGenHelperBase.ListInitializer, and Loyc.LLParserGenerator.CodeGenHelperBase.ListType.

◆ ShouldGenerateSwitch()

virtual bool Loyc.LLParserGenerator.CodeGenHelperBase.ShouldGenerateSwitch	(	IPGTerminalSet[]	sets,
		MSet< int >	casesToInclude,
		bool	hasErrorBranch
	)

inlinevirtual

Decides whether to use a switch() and for which cases, using BaseCostForSwitch and GetRelativeCostForSwitch.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.Collections.MSet< T >.Add(), Loyc.LLParserGenerator.CodeGenHelperBase.BaseCostForSwitch, and Loyc.LLParserGenerator.CodeGenHelperBase.GetRelativeCostForSwitch().

◆ VisitInput()

virtual LNode Loyc.LLParserGenerator.CodeGenHelperBase.VisitInput	(	LNode	stmt,
		IMessageSink	sink
	)

inlinevirtual

In case the IPGCodeGenHelper is interested, the LLLPG macro calls this method on each statement in the body of the macro (as a preprocessing step, before LLLPG looks at it). No action is required.

Returns: a new statement to replace the original statement, or null to do nothing.

Implements Loyc.LLParserGenerator.IPGCodeGenHelper.

References Loyc.Syntax.CodeSymbols.Alias, Loyc.Syntax.LNode.Args, Loyc.Syntax.CodeSymbols.Assign, Loyc.Syntax.LNode.Calls(), Loyc.Syntax.LNode.CallsMin(), Loyc.Syntax.LNode.Equals(), and Loyc.Syntax.CodeSymbols.Splice.

Property Documentation

◆ BaseCostForSwitch

virtual int Loyc.LLParserGenerator.CodeGenHelperBase.BaseCostForSwitch

getprotected

Used to help decide whether a "switch" or an if-else chain will be used for prediction. This is the starting cost of a switch (the starting cost of an if-else chain is set to zero).

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.ShouldGenerateSwitch().

◆ InputClass

LNode Loyc.LLParserGenerator.CodeGenHelperBase.InputClass

getset

Specifies a class or namespace to use when calling static functions. There is only one currently: NewSet(), which applies only to .

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall(), and Loyc.LLParserGenerator.GeneralCodeGenHelper.GenerateTest().

◆ InputSource

LNode Loyc.LLParserGenerator.CodeGenHelperBase.InputSource

getset

Specifies an object or class on which LLLPG APIs such as Match() and LA() should be called.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.ApiCall(), and Loyc.LLParserGenerator.CodeGenHelperBase.CreateTryWrapperForRecognizer().

◆ ListInitializer

LNode Loyc.LLParserGenerator.CodeGenHelperBase.ListInitializer

getset

Gets or sets the initializer expression for lists created with the +: operator (default: new List<T>()). The identifier "T" should appear in the expression; it will be replaced with the type of items in the list.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.SetListInitializer().

◆ ListType

LNode Loyc.LLParserGenerator.CodeGenHelperBase.ListType

getset

Gets or sets the type of lists created with the +: operator (default: List<T>). The identifier "T" should appear in the expression; it will be replaced with the type of items in the list.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.GetListType(), and Loyc.LLParserGenerator.CodeGenHelperBase.SetListInitializer().

◆ NoCheckByDefault

bool Loyc.LLParserGenerator.CodeGenHelperBase.NoCheckByDefault

getset

If true, calls to Check() are suppressed when AndPred.CheckErrorMessage is null.

Referenced by Loyc.LLParserGenerator.CodeGenHelperBase.GenerateAndPredCheck().

◆ TerminalType

LNode Loyc.LLParserGenerator.CodeGenHelperBase.TerminalType

getset

The type returned from Match() methods.

Remarks

Properties

Public Member Functions

Protected Member Functions

Protected fields

Protected static fields

Member Function Documentation

◆ ApiCall() [1/2]

◆ ApiCall() [2/2]

◆ Begin()

◆ BeginRule()

◆ CallRule()

◆ CallTryRecognizer()

◆ CodeToTerminalPred()

◆ CreateRuleMethod()

◆ CreateTryWrapperForRecognizer()

◆ Done()

◆ ErrorBranch()

◆ Example()

◆ ExampleChar()

◆ GenerateAndPredCheck()

◆ GenerateMatch()

◆ GenerateMatchExpr()

◆ GenerateSetDecl()

◆ GenerateSkip()

◆ GenerateSwitch()

◆ GenerateTest() [1/2]

◆ GenerateTest() [2/2]

◆ GetCases()

◆ GetListType()

◆ GetRelativeCostForSwitch()

◆ LA()

◆ LAType()

◆ MakeInitializedVarDecl()

◆ Optimize()

◆ ResolveAlias()

◆ SetListInitializer()

◆ ShouldGenerateSwitch()

◆ VisitInput()

Property Documentation

◆ BaseCostForSwitch

◆ InputClass

◆ InputSource

◆ ListInitializer

◆ ListType

◆ NoCheckByDefault

◆ TerminalType