C# Class Loyc.LLParserGenerator.CodeGenHelperBase

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.

Inheritance: IPGCodeGenHelper

Show file Open project: qwertie/ecsharp Class Usage Examples

Protected Properties

Property	Type	Description
F	Loyc.Syntax.LNodeFactory
_Check	Symbol
_Error	Symbol
_LA	Symbol
_LA0	Symbol
_Match	Symbol
_MatchAny	Symbol
_MatchExcept	Symbol
_MatchExceptRange	Symbol
_MatchRange	Symbol
_Skip	Symbol
_T	Symbol
_TryMatch	Symbol
_TryMatchExcept	Symbol
_TryMatchExceptRange	Symbol
_TryMatchRange	Symbol
_alias	Symbol
_classBody	WList
_currentRule	Rule
_definedAliases	LNode>.Dictionary
_setNameCounter	int
_underscore	Symbol

Public Methods

Method	Description
Begin ( WList classBody, ISourceFile sourceFile ) : void
BeginRule ( Rule rule ) : void
CallRule ( RuleRef rref, bool recognizerMode ) : LNode
CallTryRecognizer ( RuleRef rref, int lookahead ) : LNode
CodeGenHelperBase ( ) : System
CodeToTerminalPred ( LNode expr, string &errorMsg ) : Pred
CreateRuleMethod ( Rule rule, VList methodBody ) : LNode
CreateTryWrapperForRecognizer ( Rule rule ) : LNode	See IPGCodeGenHelper.CreateTryWrapperForRecognizer for more information.
Done ( ) : void
ErrorBranch ( IPGTerminalSet covered, int laIndex ) : LNode	Generates code for the default error branch of prediction (called when there is no explicit error branch).
Example ( IPGTerminalSet set ) : string
ExampleChar ( IPGTerminalSet set ) : char?
GenerateAndPredCheck ( AndPred andPred, LNode code, int li ) : LNode	Generate code to check an and-predicate during or after prediction, e.g. &!{foo} becomes !(foo) during prediction and Check(!(foo)); afterward. LLLPG substitutes $LI and $LA before it calls this method. This method can return null to suppress the Check statement.
GenerateMatch ( IPGTerminalSet set, bool savingResult, bool recognizerMode ) : LNode
GenerateMatchExpr ( IPGTerminalSet set, bool savingResult, bool recognizerMode ) : LNode	Generate code to match a set, e.g. `@{ MatchRange('a', 'z');` or `@{ MatchExcept('\n', '\r'); }`. If the set is too complex, a declaration for it is created in classBody.
GenerateSkip ( bool savingResult ) : LNode	Returns `(Skip())`, or `(MatchAny())` if the result is to be saved.
GenerateSwitch ( IPGTerminalSet branchSets, MSet casesToInclude, LNode branchCode, LNode defaultBranch, LNode laVar ) : LNode
GenerateTest ( IPGTerminalSet set, LNode laVar ) : LNode
GetListType ( LNode type ) : LNode
LA ( int k ) : LNode	Generates code to read LA(k).
LAType ( ) : LNode	Returns the data type of LA(k)
MakeInitializedVarDecl ( LNode type, bool wantList, Symbol varName ) : LNode
Optimize ( IPGTerminalSet set, IPGTerminalSet dontcare ) : IPGTerminalSet
ResolveAlias ( LNode expr ) : LNode
SetListInitializer ( LNode varDecl ) : void	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`.
ShouldGenerateSwitch ( IPGTerminalSet sets, MSet casesToInclude, bool hasErrorBranch ) : bool	Decides whether to use a switch() and for which cases, using BaseCostForSwitch and GetRelativeCostForSwitch.
VisitInput ( LNode stmt, IMessageSink sink ) : LNode

Protected Methods

Method	Description
ApiCall ( Symbol apiName ) : LNode	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')`.
ApiCall ( Symbol apiName, IEnumerable args, bool isStatic = false ) : LNode	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')`.
ApiType ( LNode typeName ) : LNode
DefaultOf ( LNode type, bool wantList ) : LNode
EndMayBeReachable ( LNode stmt ) : bool
GenerateSetDecl ( IPGTerminalSet set, Symbol setName ) : LNode	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');`
GenerateSetDecl ( IPGTerminalSet set ) : Symbol
GenerateSetName ( Rule currentRule ) : Symbol
GenerateTest ( IPGTerminalSet set, LNode subject, Symbol setName ) : LNode	Generates code to test whether a terminal is in the set. 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.
GetCases ( IPGTerminalSet set ) : IEnumerable	Gets the literals or symbols to use for switch cases of a set (just the values, not including the case labels.)
GetRelativeCostForSwitch ( IPGTerminalSet set ) : int	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.

Private Methods

Method	Description
AddSwitchHandler ( LNode branch, WList stmts ) : void
ForwardedArgList ( LNode args ) : VList
ReplaceT ( LNode expr, LNode replacement ) : LNode
VarName ( LNode varStmt ) : LNode

Method Details

ApiCall() protected method

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').

protected ApiCall ( Symbol apiName ) : LNode
apiName	Symbol
return	LNode

ApiCall() protected method

protected ApiCall ( Symbol apiName, IEnumerable args, bool isStatic = false ) : LNode
apiName	Symbol
args	IEnumerable	Parameters to the API call, or null to access a /// property or field.
isStatic	bool
return	LNode

ApiType() protected method

protected ApiType ( LNode typeName ) : LNode
typeName	LNode
return	LNode

Begin() public method

public Begin ( WList classBody, ISourceFile sourceFile ) : void
classBody	WList
sourceFile	ISourceFile
return	void

BeginRule() public method

public BeginRule ( Rule rule ) : void
rule	Rule
return	void

CallRule() public method

public CallRule ( RuleRef rref, bool recognizerMode ) : LNode
rref	RuleRef
recognizerMode	bool
return	LNode

CallTryRecognizer() public method

public CallTryRecognizer ( RuleRef rref, int lookahead ) : LNode
rref	RuleRef
lookahead	int
return	LNode

CodeGenHelperBase() public method

public CodeGenHelperBase ( ) : System
return	System

CodeToTerminalPred() public abstract method

public abstract CodeToTerminalPred ( LNode expr, string &errorMsg ) : Pred
expr	LNode
errorMsg	string
return	Pred

CreateRuleMethod() public method

public CreateRuleMethod ( Rule rule, VList methodBody ) : LNode
rule	Rule
methodBody	VList
return	LNode

CreateTryWrapperForRecognizer() public method

See IPGCodeGenHelper.CreateTryWrapperForRecognizer for more information.

public CreateTryWrapperForRecognizer ( Rule rule ) : LNode
rule	Rule
return	LNode

DefaultOf() protected method

protected DefaultOf ( LNode type, bool wantList ) : LNode
type	LNode
wantList	bool
return	LNode

Done() public method

public Done ( ) : void
return	void

EndMayBeReachable() protected static method

protected static EndMayBeReachable ( LNode stmt ) : bool
stmt	LNode
return	bool

ErrorBranch() public method

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

public ErrorBranch ( IPGTerminalSet covered, int laIndex ) : LNode
covered	IPGTerminalSet	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	int	Location of unexpected input, relative to current position.
return	LNode

Example() public abstract method

public abstract Example ( IPGTerminalSet set ) : string
set	IPGTerminalSet
return	string

ExampleChar() public method

public ExampleChar ( IPGTerminalSet set ) : char?
set	IPGTerminalSet
return	char?

GenerateAndPredCheck() public method

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

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

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

GenerateMatch() public method

public GenerateMatch ( IPGTerminalSet set, bool savingResult, bool recognizerMode ) : LNode
set	IPGTerminalSet
savingResult	bool
recognizerMode	bool
return	LNode

GenerateMatchExpr() public abstract method

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

public abstract GenerateMatchExpr ( IPGTerminalSet set, bool savingResult, bool recognizerMode ) : LNode
set	IPGTerminalSet
savingResult	bool
recognizerMode	bool
return	LNode

GenerateSetDecl() protected abstract method

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');

protected abstract GenerateSetDecl ( IPGTerminalSet set, Symbol setName ) : LNode
set	IPGTerminalSet
setName	Symbol
return	LNode

GenerateSetDecl() protected method

protected GenerateSetDecl ( IPGTerminalSet set ) : Symbol
set	IPGTerminalSet
return	Symbol

GenerateSetName() protected method

protected GenerateSetName ( Rule currentRule ) : Symbol
currentRule	Rule
return	Symbol

GenerateSkip() public method

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

public GenerateSkip ( bool savingResult ) : LNode
savingResult	bool
return	LNode

GenerateSwitch() public method

public GenerateSwitch ( IPGTerminalSet branchSets, MSet casesToInclude, LNode branchCode, LNode defaultBranch, LNode laVar ) : LNode
branchSets	IPGTerminalSet
casesToInclude	MSet
branchCode	LNode
defaultBranch	LNode
laVar	LNode
return	LNode

GenerateTest() public method

public GenerateTest ( IPGTerminalSet set, LNode laVar ) : LNode
set	IPGTerminalSet
laVar	LNode
return	LNode

GenerateTest() protected abstract method

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

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.

protected abstract GenerateTest ( IPGTerminalSet set, LNode subject, Symbol setName ) : LNode
set	IPGTerminalSet
subject	LNode	Represents the variable to be tested.
setName	Symbol	Names an external set variable to use for the test.
return	LNode

GetCases() protected method

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

protected GetCases ( IPGTerminalSet set ) : IEnumerable
set	IPGTerminalSet
return	IEnumerable

GetListType() public method

public GetListType ( LNode type ) : LNode
type	LNode
return	LNode

GetRelativeCostForSwitch() protected method

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.

protected GetRelativeCostForSwitch ( IPGTerminalSet set ) : int
set	IPGTerminalSet
return	int

LA() public method

Generates code to read LA(k).

public LA ( int k ) : LNode
k	int
return	LNode

LAType() public abstract method

Returns the data type of LA(k)

public abstract LAType ( ) : LNode
return	LNode

MakeInitializedVarDecl() public method

public MakeInitializedVarDecl ( LNode type, bool wantList, Symbol varName ) : LNode
type	LNode
wantList	bool
varName	Symbol
return	LNode

Optimize() public method

public Optimize ( IPGTerminalSet set, IPGTerminalSet dontcare ) : IPGTerminalSet
set	IPGTerminalSet
dontcare	IPGTerminalSet
return	IPGTerminalSet

ResolveAlias() public method

public ResolveAlias ( LNode expr ) : LNode
expr	LNode
return	LNode

SetListInitializer() public method

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.

public SetListInitializer ( LNode varDecl ) : void
varDecl	LNode
return	void

ShouldGenerateSwitch() public method

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

public ShouldGenerateSwitch ( IPGTerminalSet sets, MSet casesToInclude, bool hasErrorBranch ) : bool
sets	IPGTerminalSet
casesToInclude	MSet
hasErrorBranch	bool
return	bool

VisitInput() public method

public VisitInput ( LNode stmt, IMessageSink sink ) : LNode
stmt	LNode
sink	IMessageSink
return	LNode

Property Details

F protected property

protected LNodeFactory,Loyc.Syntax F
return	Loyc.Syntax.LNodeFactory

_Check protected static property

protected static Symbol _Check
return	Symbol

_Error protected static property

protected static Symbol _Error
return	Symbol

_LA protected static property

protected static Symbol _LA
return	Symbol

_LA0 protected static property

protected static Symbol _LA0
return	Symbol

_Match protected static property

protected static Symbol _Match
return	Symbol

_MatchAny protected static property

protected static Symbol _MatchAny
return	Symbol

_MatchExcept protected static property

protected static Symbol _MatchExcept
return	Symbol

_MatchExceptRange protected static property

protected static Symbol _MatchExceptRange
return	Symbol

_MatchRange protected static property

protected static Symbol _MatchRange
return	Symbol

_Skip protected static property

protected static Symbol _Skip
return	Symbol

_T protected static property

protected static Symbol _T
return	Symbol

_TryMatch protected static property

protected static Symbol _TryMatch
return	Symbol

_TryMatchExcept protected static property

protected static Symbol _TryMatchExcept
return	Symbol

_TryMatchExceptRange protected static property

protected static Symbol _TryMatchExceptRange
return	Symbol

_TryMatchRange protected static property

protected static Symbol _TryMatchRange
return	Symbol

_alias protected static property

protected static Symbol _alias
return	Symbol

_classBody protected property

protected WList _classBody
return	WList

_currentRule protected property

protected Rule,Loyc.LLParserGenerator _currentRule
return	Rule

_definedAliases protected property

protected Dictionary _definedAliases
return	LNode>.Dictionary

_setNameCounter protected property

protected int _setNameCounter
return	int

_underscore protected static property

protected static Symbol _underscore
return	Symbol