Package org.basex.query

Class CompileContext

java.lang.Object

org.basex.query.CompileContext

public final class CompileContext
extends Object

Compilation context.

Author:

BaseX Team 2005-22, BSD License, Christian Gruen

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CompileContext.Simplify	Compile-time simplifications.

Field Summary

Fields

Modifier and Type	Field	Description
boolean	dynamic	Dynamic compilation.
static int	MAX_PREEVAL	Limit for the size of sequences that are pre-evaluated.
QueryContext	qc	Query context.

Constructor Summary

Constructors

Constructor	Description
CompileContext(QueryContext qc, boolean dynamic)	Constructor.

Method Summary

Modifier and Type	Method	Description
Expr	compileOrError(Expr expr, boolean error)	Compiles an expression or creates an error.
Var	copy(Var var, IntObjMap<Var> vm)	Creates a new copy of the given variable in this scope.
Expr	emptySeq(Expr expr)	Replaces the specified expression with an empty sequence.
StandardFunc	error(QueryException qe, Expr expr)	Creates an error function instance.
Expr	function(AFunction function, InputInfo ii, Expr... exprs)	Creates and returns an optimized instance of the specified function.
Expr	get(Expr expr, QuerySupplier<Expr> func)	Evaluates a function in the given focus.
void	info(String string, Object... ext)	Adds some compilation info.
Expr	merge(Expr expr, Expr result, InputInfo ii)	Creates a list expression from an expression to be swallowed and a result expression.
boolean	nestedFocus()	Indicates if the query focus is nested.
boolean	ok(Expr expr, QuerySupplier<Boolean> func)	Evaluates a function in the given focus.
Expr	preEval(Expr expr)	Pre-evaluates the specified expression.
void	pushFocus(Expr expr)	Pushes the current query focus onto the stack and, if possible, assigns a new dummy item.
void	pushScope(VarScope vs)	Pushes a new variable scope to the stack.
void	removeFocus()	Removes the current query focus from the stack.
VarScope	removeScope()	Removes and returns the current variable scope.
void	removeScope(Scope scope)	Prepares the variable scope for being compiled.
Expr	replaceWith(Expr expr, Expr result)	Replaces an expression with the specified one.
Expr	replicate(Expr expr, Expr count, InputInfo ii)	Replicates an expression.
StaticContext	sc()	Returns the current static context.
Expr	simplify(Expr expr, Expr result, CompileContext.Simplify mode)	Replaces an expression with a simplified one and simplifies the result expression.
ExprList	unroll(Expr expr, boolean items)	Returns an expression list for unrolling an expression.
void	updateFocus(Expr expr)	Assigns a new dummy item to the query focus.
VarScope	vs()	Returns the current variable scope.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_PREEVAL

public static final int MAX_PREEVAL

Limit for the size of sequences that are pre-evaluated.

See Also:

Constant Field Values

qc

public final QueryContext qc

Query context.

dynamic

public final boolean dynamic

Dynamic compilation.

Constructor Detail

CompileContext

public CompileContext(QueryContext qc,
                      boolean dynamic)

Constructor.

Parameters:

qc - query context

dynamic - dynamic compilation

Method Detail

info

public void info(String string,
                 Object... ext)

Adds some compilation info.

Parameters:

string - evaluation info

ext - text text extensions

pushScope

public void pushScope(VarScope vs)

Pushes a new variable scope to the stack.

Parameters:

vs - variable scope

removeScope

public VarScope removeScope()

Removes and returns the current variable scope.

Returns:

the removed element

removeScope

public void removeScope(Scope scope)

Prepares the variable scope for being compiled. This method should be run after compiling a scope.

Parameters:

scope - scope

pushFocus

public void pushFocus(Expr expr)

Pushes the current query focus onto the stack and, if possible, assigns a new dummy item.

Parameters:

expr - focus expression (can be null)

updateFocus

public void updateFocus(Expr expr)

Assigns a new dummy item to the query focus.

Parameters:

expr - focus expression

get

public Expr get(Expr expr,
                QuerySupplier<Expr> func)
         throws QueryException

Evaluates a function in the given focus.

Parameters:

expr - focus expression (can be null)

func - function to evaluate

Returns:

resulting expression

Throws:

QueryException - query exception

ok

public boolean ok(Expr expr,
                  QuerySupplier<Boolean> func)
           throws QueryException

Evaluates a function in the given focus.

Parameters:

expr - focus expression (can be null)

func - function to evaluate

Returns:

result of check

Throws:

QueryException - query exception

removeFocus

public void removeFocus()

Removes the current query focus from the stack.

nestedFocus

public boolean nestedFocus()

Indicates if the query focus is nested.

Returns:

result of check

vs

public VarScope vs()

Returns the current variable scope.

Returns:

variable scope

sc

public StaticContext sc()

Returns the current static context.

Returns:

static context

copy

public Var copy(Var var,
                IntObjMap<Var> vm)

Creates a new copy of the given variable in this scope.

Parameters:

var - variable to copy (can be null)

vm - variable mapping (can be null)

Returns:

new variable, or null if the supplied variable is null

preEval

public Expr preEval(Expr expr)
             throws QueryException

Pre-evaluates the specified expression.

Parameters:

expr - expression

Returns:

optimized expression

Throws:

QueryException - query exception

emptySeq

public Expr emptySeq(Expr expr)

Replaces the specified expression with an empty sequence.

Parameters:

expr - original expression

Returns:

optimized expression

simplify

public Expr simplify(Expr expr,
                     Expr result,
                     CompileContext.Simplify mode)
              throws QueryException

Replaces an expression with a simplified one and simplifies the result expression. As the simplified expression may have a different type, no type refinement is performed.

Parameters:

expr - original expression

result - resulting expression

mode - mode of simplification

Returns:

optimized expression

Throws:

QueryException - query exception

replaceWith

public Expr replaceWith(Expr expr,
                        Expr result)

Replaces an expression with the specified one.

Parameters:

expr - original expression

result - resulting expression

Returns:

optimized expression

error

public StandardFunc error(QueryException qe,
                          Expr expr)

Creates an error function instance.

Parameters:

qe - exception to be raised

expr - expression that caused the error message

Returns:

function

compileOrError

public Expr compileOrError(Expr expr,
                           boolean error)
                    throws QueryException

Compiles an expression or creates an error.

Parameters:

expr - expression

error - return error

Returns:

compiled expression or error.

Throws:

QueryException - query exception

function

public Expr function(AFunction function,
                     InputInfo ii,
                     Expr... exprs)
              throws QueryException

Creates and returns an optimized instance of the specified function.

Parameters:

function - function

ii - input info

exprs - expressions

Returns:

function

Throws:

QueryException - query exception

merge

public Expr merge(Expr expr,
                  Expr result,
                  InputInfo ii)
           throws QueryException

Creates a list expression from an expression to be swallowed and a result expression.

Parameters:

expr - expression to be swallowed

result - result expression

ii - input info

Returns:

function

Throws:

QueryException - query exception

replicate

public Expr replicate(Expr expr,
                      Expr count,
                      InputInfo ii)
               throws QueryException

Replicates an expression.

Parameters:

expr - expression

count - count expression

ii - input info

Returns:

function

Throws:

QueryException - query exception

unroll

public ExprList unroll(Expr expr,
                       boolean items)

Returns an expression list for unrolling an expression.

Parameters:

expr - expression to analyze

items - unroll lists only if all its expressions yield items the number of which do not exceed limit

Returns:

expression list or null