public final class Let extends GFLWOR.Clause
let
clause, binding an expression to a variable.Modifier and Type | Field and Description |
---|---|
Expr |
expr
Bound expression.
|
Var |
var
Item variable.
|
Constructor and Description |
---|
Let(Var var,
Expr expr,
boolean score,
InputInfo info)
Constructor.
|
Modifier and Type | Method and Description |
---|---|
boolean |
accept(ASTVisitor visitor)
Traverses this expression, notifying the visitor of declared and used variables,
and checking the tree for other recursive properties.
|
void |
checkUp()
Checks if all updating expressions are correctly placed.
|
GFLWOR.Clause |
compile(QueryContext qc,
VarScope scp)
Compiles and optimizes the expression, assigns types and cardinalities.
|
Let |
copy(QueryContext qc,
VarScope scp,
IntObjMap<Var> vs)
Copies an expression.
|
VarUsage |
count(Var v)
Checks how often a variable is used in this expression.
|
int |
exprSize()
Counts the number of expressions in this expression's sub-tree.
|
boolean |
has(Expr.Flag flag)
Indicates if an expression has the specified compiler property.
|
GFLWOR.Clause |
inline(QueryContext qc,
VarScope scp,
Var v,
Expr ex)
Inlines an expression into this one, replacing all references to the given variable.
|
Let |
optimize(QueryContext qc,
VarScope scp)
Optimizes an already compiled expression without recompiling its sub-expressions.
|
void |
plan(FElem plan)
Creates an expression tree.
|
boolean |
removable(Var v)
Checks if the specified variable is replaceable by a context value.
|
String |
toString() |
declares, item, iter, value, vars
atomItem, atomValue, checkAtomic, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, compBln, copyType, ctxValue, ebv, optPre, optPre, preEval, seqType, seqType, size, test, toArray, toArray, toAtomItem, toB64, toB64, toBin, toBin, toBoolean, toBoolean, toBytes, toBytes, toDouble, toDouble, toElem, toEmptyNode, toEmptyToken, toFloat, toFunc, toItem, toLong, toLong, toMap, toMap, toNode, toNode, toNumber, toQNm, toQNm, toToken, toToken
atomIter, data, hasFreeVars, indexAccessible, inlineAll, isEmpty, isFunction, isVacuous, isValue, iterable, markTailCalls, optimizeEbv, sameAs, typeCheck, uses, visitAll
addPlan, addPlan, description, planAttr, planElem, toErrorString
public GFLWOR.Clause compile(QueryContext qc, VarScope scp) throws QueryException
Expr
QueryContext.compile()
.qc
- query contextscp
- variable scopeQueryException
- query exceptionpublic Let optimize(QueryContext qc, VarScope scp) throws QueryException
Expr
optimize
in class GFLWOR.Clause
qc
- query contextscp
- variable scopeQueryException
- query exceptionpublic Let copy(QueryContext qc, VarScope scp, IntObjMap<Var> vs)
Expr
copy
in class GFLWOR.Clause
qc
- query contextscp
- variable scope for creating new variablesvs
- mapping from old variable IDs to new variable copiespublic boolean accept(ASTVisitor visitor)
Expr
public void plan(FElem plan)
ExprInfo
public final boolean has(Expr.Flag flag)
Expr
true
if at least one test is successful.public final boolean removable(Var v)
Expr
Preds.removable(org.basex.query.var.Var)
if one of the variables is used within a predicate.Path.removable(org.basex.query.var.Var)
if the variable occurs within the path.GFLWOR.compile(QueryContext, VarScope)
to rewrite where
clauses into predicates.public final VarUsage count(Var v)
Expr
SwitchCase.countCases(org.basex.query.var.Var)
or (indirectly)
GFLWOR.inlineLets(org.basex.query.QueryContext, org.basex.query.var.VarScope)
.public final GFLWOR.Clause inline(QueryContext qc, VarScope scp, Var v, Expr ex) throws QueryException
Expr
GFLWOR.inlineLets(org.basex.query.QueryContext, org.basex.query.var.VarScope)
and For.toPredicate(org.basex.query.QueryContext, org.basex.query.var.VarScope, org.basex.query.expr.Expr)
,
and the variable reference is replaced in VarRef.inline(org.basex.query.QueryContext, org.basex.query.var.VarScope, org.basex.query.var.Var, org.basex.query.expr.Expr)
.inline
in class GFLWOR.Clause
qc
- query context for reoptimizationscp
- variable scope for reoptimizationv
- variable to replaceex
- expression to inlinenull
otherwiseQueryException
- query exceptionpublic final void checkUp() throws QueryException
Expr
checkUp
in class Expr
QueryException
- query exceptionpublic final int exprSize()
Expr
StaticFunc.inline(org.basex.query.QueryContext, org.basex.query.util.list.AnnList, org.basex.query.expr.Expr)
to check if an expression
is small enough to be inlined.Copyright © 2005–2015 BaseX Team. All rights reserved.