Package org.basex.query.func

Class Closure

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Single

org.basex.query.func.Closure

All Implemented Interfaces:

XQFunctionExpr, Scope

public final class Closure
extends Single
implements Scope, XQFunctionExpr

Inline function.

Author:

BaseX Team 2005-21, BSD License, Leo Woerteler

Field Summary

Fields inherited from class org.basex.query.expr.Single

expr

Fields inherited from class org.basex.query.expr.ParseExpr

exprType, info

Constructor Summary

Constructors

Constructor	Description
Closure(InputInfo info, SeqType declType, Var[] params, Expr expr, AnnList anns, Map<Var,Expr> global, VarScope vs)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	accept(ASTVisitor visitor)	Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.
AnnList	annotations()	Annotations of this function.
int	arity()	Number of arguments this function takes.
void	checkUp()	Checks if the updating semantics are satisfied.
void	comp(CompileContext cc)	Compiles the expression contained in this scope.
Expr	compile(CompileContext cc)	Compiles and optimizes the expression, assigns types and cardinalities.
boolean	compiled()	Checks if this scope has already been compiled.
Expr	copy(CompileContext cc, IntObjMap<Var> vm)	Copies an expression.
VarUsage	count(Var var)	Checks how often a variable or context reference is used in this expression.
boolean	equals(Object obj)	This function is e.g.
int	exprSize()	Counts the number of expressions in this expression's sub-tree.
QNm	funcName()	Name of this function, null means anonymous function.
FuncType	funcType()	Returns the function type of this expression.
Iterator<Map.Entry<Var,Expr>>	globalBindings()	Returns an iterator over the non-local bindings of this closure.
boolean	has(Flag... flags)	Indicates if an expression has one of the specified compiler properties.
Expr	inline(Expr[] exprs, CompileContext cc)	Tries to inline this function with the given arguments.
Expr	inline(InlineContext ic)	Inlines an expression into this one, replacing all variable or context references.
boolean	inlineable(InlineContext ic)	Checks if inlining is possible.
FuncItem	item(QueryContext qc, InputInfo ii)	Evaluates the expression and returns the resulting item, or Empty.VALUE if the expression yields an empty sequence.
Expr	optimize(CompileContext cc)	Optimizes an already compiled expression without recompiling its sub-expressions.
QNm	paramName(int pos)	Name of the parameter at the given position.
void	plan(QueryPlan plan)	Creates a query plan.
void	plan(QueryString qs)	Creates a query string.
static Closure	undeclaredLiteral(QNm name, int arity, QueryContext qc, StaticContext sc, InputInfo ii)	Creates a function literal for a function that was not yet encountered while parsing.
boolean	vacuous()	Tests if this is a vacuous expression (empty sequence or error function).
boolean	vacuousBody()	Checks if this function returns vacuous results (see Expr.vacuous()).
boolean	visit(ASTVisitor visitor)	Traverses this scope with the given ASTVisitor.

Methods inherited from class org.basex.query.expr.ParseExpr

adoptType, atomValue, checkAllUp, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, checkType, checkUp, copyType, ctxValue, ebv, iter, refineType, seqType, size, test, toArray, toArray, toAtomItem, toB64, toB64, toBin, toBin, toBoolean, toBoolean, toBytes, toBytes, toDouble, toDouble, toElem, toFloat, toFunc, toItem, toItem, toLong, toLong, toMap, toMap, toNode, toNode, toNodeOrNull, toNumber, toNumberOrNull, toQNm, toQNm, toToken, toToken, toTokenOrNull, toZeroToken, value

Methods inherited from class org.basex.query.expr.Expr

arg, args, atomItem, atomIter, data, data, ddo, hasFreeVars, indexAccessible, isSimple, markTailCalls, mergeEbv, simplifyFor, typeCheck, uses, visitAll

Methods inherited from class org.basex.query.expr.ExprInfo

description, toErrorString, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

Closure

public Closure(InputInfo info,
 SeqType declType,
 Var[] params,
 Expr expr,
 AnnList anns,
 Map<Var,Expr> global,
 VarScope vs)

Constructor.

Parameters:

info - input info

declType - declared type (can be null)

params - formal parameters

expr - function body

anns - annotations

global - bindings for non-local variables

vs - scope

Method Details

arity

public int arity()

Description copied from interface: XQFunctionExpr

Number of arguments this function takes.

Specified by:

arity in interface XQFunctionExpr

Returns:

function arity

funcName

public QNm funcName()

Description copied from interface: XQFunctionExpr

Name of this function, null means anonymous function.

Specified by:

funcName in interface XQFunctionExpr

Returns:

name or null

paramName

public QNm paramName(int pos)

Description copied from interface: XQFunctionExpr

Name of the parameter at the given position.

Specified by:

paramName in interface XQFunctionExpr

Parameters:

pos - position of the parameter

Returns:

name of the parameter

funcType

public FuncType funcType()

Description copied from class: Expr

Returns the function type of this expression.

Specified by:

funcType in interface XQFunctionExpr

Overrides:

funcType in class Expr

Returns:

function type, or null if expression yields no functions

annotations

public AnnList annotations()

Description copied from interface: XQFunctionExpr

Annotations of this function.

Specified by:

annotations in interface XQFunctionExpr

Returns:

this function's annotations

comp

public void comp(CompileContext cc)
          throws QueryException

Description copied from interface: Scope

Compiles the expression contained in this scope.

Specified by:

comp in interface Scope

Parameters:

cc - compilation context

Throws:

QueryException - compilation errors

compile

public Expr compile(CompileContext cc)
             throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns types and cardinalities.

Overrides:

compile in class Single

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

optimize

public Expr optimize(CompileContext cc)
              throws QueryException

Description copied from class: Expr

Optimizes an already compiled expression without recompiling its sub-expressions.

Overrides:

optimize in class Single

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

count

public VarUsage count(Var var)

Description copied from class: Expr

Checks how often a variable or context reference is used in this expression. This function is called by:

• optimize(org.basex.query.CompileContext)
• GFLWOR.inlineForLet(org.basex.query.CompileContext)
• GFLWOR.optimizePos(org.basex.query.CompileContext)
• GFLWOR.simplify(org.basex.query.CompileContext)
• GFLWOR.unusedVars(org.basex.query.CompileContext)
• SimpleMap.optimize(org.basex.query.CompileContext)
• TypeswitchGroup.optimize(org.basex.query.CompileContext)

Overrides:

count in class Single

Parameters:

var - variable (Var reference) or context (null) to inline

Returns:

number of usages, see VarUsage

inline

public Expr inline(InlineContext ic)
            throws QueryException

Description copied from class: Expr

Inlines an expression into this one, replacing all variable or context references. This function is called by InlineContext.inline(Expr) (see invocations of this functions for further inlinings). The variable reference is replaced in:

• OrderBy.inline(org.basex.query.InlineContext)
• VarRef.inline(org.basex.query.InlineContext)

The context is replaced in:

• ContextFn.inline(org.basex.query.InlineContext)
• ContextValue.inline(org.basex.query.InlineContext)
• Arr.inline(org.basex.query.InlineContext)

Overrides:

inline in class Single

Parameters:

ic - inlining context

Returns:

resulting expression if something has changed, null otherwise

Throws:

QueryException - query exception

copy

public Expr copy(CompileContext cc,
 IntObjMap<Var> vm)

Description copied from class: Expr

Copies an expression. Used for inlining functions, or for copying static queries. It is utilized by VarRef.inline(org.basex.query.InlineContext), FuncItem.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext), inline(org.basex.query.InlineContext) and StaticFunc.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext).

Specified by:

copy in class Expr

Parameters:

cc - compilation context

vm - mapping from old variable IDs to new variable copies. Required by copy(org.basex.query.CompileContext, org.basex.util.hash.IntObjMap<org.basex.query.var.Var>) and VarRef.copy(org.basex.query.CompileContext, org.basex.util.hash.IntObjMap<org.basex.query.var.Var>)

Returns:

copied expression

inline

public Expr inline(Expr[] exprs,
 CompileContext cc)
            throws QueryException

Description copied from interface: XQFunctionExpr

Tries to inline this function with the given arguments.

Specified by:

inline in interface XQFunctionExpr

Parameters:

exprs - arguments

cc - compilation context

Returns:

the expression to inline if successful, null otherwise

Throws:

QueryException - query exception

item

public FuncItem item(QueryContext qc,
 InputInfo ii)
              throws QueryException

Description copied from class: Expr

Evaluates the expression and returns the resulting item, or Empty.VALUE if the expression yields an empty sequence. If this method is not implemented, Expr.value(QueryContext) must be implemented instead.

Overrides:

item in class ParseExpr

Parameters:

qc - query context

ii - input info (only required by Seq instances, which have no input info)

Returns:

item or Empty.VALUE

Throws:

QueryException - query exception

has

public boolean has(Flag... flags)

Description copied from class: Expr

Indicates if an expression has one of the specified compiler properties. This method must only be called at compile time. It is invoked to test properties of sub-expressions. It returns true if at least flag matches an expression.

Overrides:

has in class Single

Parameters:

flags - flags to be checked

Returns:

result of check

inlineable

public boolean inlineable(InlineContext ic)

Description copied from class: Expr

Checks if inlining is possible. This function is called by InlineContext.inlineable(org.basex.query.expr.Expr...) and: CNode.inlineable(org.basex.query.InlineContext) returns false if the new expression construct new nodes. The following tests might reject inlining if the expression is a context reference:

• Preds.inlineable(org.basex.query.InlineContext)
• Path.inlineable(org.basex.query.InlineContext)
• SimpleMap.inlineable(org.basex.query.InlineContext)
• StaticJavaCall.inlineable(org.basex.query.InlineContext)
• TransformWith.inlineable(org.basex.query.InlineContext)

Overrides:

inlineable in class Single

Parameters:

ic - inlining context

Returns:

result of check

visit

public boolean visit(ASTVisitor visitor)

Description copied from interface: Scope

Traverses this scope with the given ASTVisitor.

Specified by:

visit in interface Scope

Parameters:

visitor - visitor

Returns:

continue flag

checkUp

public void checkUp()
             throws QueryException

Description copied from class: Expr

Checks if the updating semantics are satisfied. This function is only called if any updating expression was found in the query.

Overrides:

checkUp in class Single

Throws:

QueryException - query exception

vacuous

public boolean vacuous()

Description copied from class: Expr

Tests if this is a vacuous expression (empty sequence or error function). This check is needed for updating queries.

Overrides:

vacuous in class Expr

Returns:

result of check

vacuousBody

public boolean vacuousBody()

Description copied from interface: XQFunctionExpr

Checks if this function returns vacuous results (see Expr.vacuous()).

Specified by:

vacuousBody in interface XQFunctionExpr

Returns:

result of check

accept

public boolean accept(ASTVisitor visitor)

Description copied from class: Expr

Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.

Overrides:

accept in class Single

Parameters:

visitor - visitor

Returns:

if the walk should be continued

exprSize

public int exprSize()

Description copied from class: Expr

Counts the number of expressions in this expression's sub-tree. This method is e.g. called by StaticFunc.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext) to check if an expression is small enough to be inlined.

Overrides:

exprSize in class Single

Returns:

number of expressions

compiled

public boolean compiled()

Description copied from interface: Scope

Checks if this scope has already been compiled.

Specified by:

compiled in interface Scope

Returns:

result of check

globalBindings

public Iterator<Map.Entry<Var,Expr>> globalBindings()

Returns an iterator over the non-local bindings of this closure.

Returns:

the iterator

undeclaredLiteral

public static Closure undeclaredLiteral(QNm name,
 int arity,
 QueryContext qc,
 StaticContext sc,
 InputInfo ii)
                                 throws QueryException

Creates a function literal for a function that was not yet encountered while parsing.

Parameters:

name - function name

arity - function arity

qc - query context

sc - static context

ii - input info

Returns:

function literal

Throws:

QueryException - query exception

equals

public boolean equals(Object obj)

Description copied from class: Single

This function is e.g. called by:

• If.optimize(CompileContext), Switch.optimize(CompileContext), Typeswitch.optimize(CompileContext), in order to discard identical expressions.
• CmpR.mergeEbv(Expr, boolean, CompileContext) or CmpSR.mergeEbv(Expr, boolean, CompileContext), in order to merge expressions with identical input.
• CmpG.optimize(CompileContext) or CmpV.optimize(CompileContext), in order to pre-evaluate equality tests.
• CmpG.optimize(CompileContext) or Pos.get(Expr, CmpV.OpV, InputInfo, CompileContext), in order to compare the start and end value.
• PathCache, in order to find identical root values at runtime.

Must be overwritten by implementing class.

Overrides:

equals in class Single

plan

public void plan(QueryPlan plan)

Description copied from class: ExprInfo

Creates a query plan.

Overrides:

plan in class Single

Parameters:

plan - expression plan

plan

public void plan(QueryString qs)

Description copied from class: ExprInfo

Creates a query string.

Specified by:

plan in class ExprInfo

Parameters:

qs - query string builder