hlt.language.design.kernel

Class Comprehension

java.lang.Object

hlt.language.design.kernel.Expression

hlt.language.design.kernel.ProtoExpression

hlt.language.design.kernel.Comprehension

All Implemented Interfaces:

Locatable

public class Comprehension
extends ProtoExpression

This class represents a monoid comprehension whose actual form is interpreted as a construct involving the parts of the syntactic form of the comprehension. The syntax of a monoid comprehension is given by an expression of the form:

 [op,id] { e | q1, ..., qn }
 

where [op,id] define a monoid, e is an expression, and the q_is are qualifiers. A qualifier is either a boolean expression or a pair p <- e, where p is a pattern (any expression) and e is an expression. The sequence of qualifiers may also be empty. Such a monoid comprehension is syntactic sugar that is in fact translated into a combination of homomorphisms and/or filtering tests, possibly wrapped inside a let factoring out some computation.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Comprehension.IndexedExpression
class	Comprehension.Qualifier
class	Comprehension.RawInfo

Field Summary

Fields

Modifier and Type	Field and Description
boolean	_doLetWrapping
static boolean	OPAQUE_PARAMETERS

Fields inherited from class hlt.language.design.kernel.Expression

VOID_ASSIGNMENTS

Constructor Summary

Constructors

Constructor and Description
Comprehension(java.util.AbstractList parameters, java.util.AbstractList values, Expression body) Constructs an already translated comprehension as a let.
Comprehension(Tables tables, Expression operation, Expression identity, Expression expression, java.util.AbstractList patterns, java.util.AbstractList expressions) Constructs a raw comprehension with the specifed arguments and assuming the default in-place mode for performing the monoid operation.
Comprehension(Tables tables, Expression operation, Expression identity, Expression expression, java.util.AbstractList patterns, java.util.AbstractList expressions, byte inPlace) Constructs a raw comprehension with the specifed arguments.

Method Summary

Methods

Modifier and Type	Method and Description
void	compile(Compiler compiler) This method compiles this expression in the context of the specified Compiler.
Expression	copy() Returns a deep copy of this expression.
Expression	identity()
int	numberOfSubexpressions() Returns the number of subexpressions
Expression	operation()
Expression	sanitizeNames(ParameterStack parameters) This method returns the actual expression corresponding to this one after eliminating all the Dummy expressions that occur in it where names where read.
void	sanitizeSorts(Enclosure enclosure) This method walks down the expression gathering information relating each Local object to the Scope containing the corresponding Parameter in its array of formal parameters.
void	setCheckedType() This method sets the final unambiguously checked type of this expression, possibly along with other final information that may be needed by the compiler for generating code.
Comprehension	setNoLetWrapping()
Expression	setSubexpression(int n, Expression expression) Returns this expression after setting its n-th subexpression to the specified expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException
Expression	subexpression(int n) Returns the n-th subexpression of this expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException
Expression	substitute(java.util.HashMap substitution) Returns the comprehension obtained after applying the specified substitution to the subexpressions of this.
Tables	tables()
java.lang.String	toString()
void	typeCheck(TypeChecker typeChecker) This method type-checks this expression in the context of the specified TypeChecker.
Expression	typedCopy() Returns a deep copy of this expression this and all its subexpressions share the same type as their copy's counterparts.

Methods inherited from class hlt.language.design.kernel.ProtoExpression

checkedType, setCheckedType, setType, type, typeRef

Methods inherited from class hlt.language.design.kernel.Expression

addType, addTypes, boxSort, containsFreeName, enclosingScope, extent, getEnd, getStart, isConstant, isEquality, isFalse, isHiddenSlicing, isNull, isSelector, isSlicing, isTrue, isVoid, locationString, otherTypes, parameters, setCheckedTypeLocked, setEnd, setExtent, setOtherTypes, setStart, shiftOffsets, shiftOffsets, sort, typeCheck, typeCheck, typeCheckLocked

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

OPAQUE_PARAMETERS

public static boolean OPAQUE_PARAMETERS

_doLetWrapping

public boolean _doLetWrapping

Constructor Detail

Comprehension

public Comprehension(java.util.AbstractList parameters,
             java.util.AbstractList values,
             Expression body)

Constructs an already translated comprehension as a let. This is provided as a public constructor but should be used with care as it trusts that the specified arguments are correctly set up.

Comprehension

public Comprehension(Tables tables,
             Expression operation,
             Expression identity,
             Expression expression,
             java.util.AbstractList patterns,
             java.util.AbstractList expressions)

Constructs a raw comprehension with the specifed arguments and assuming the default in-place mode for performing the monoid operation.

Comprehension

public Comprehension(Tables tables,
             Expression operation,
             Expression identity,
             Expression expression,
             java.util.AbstractList patterns,
             java.util.AbstractList expressions,
             byte inPlace)

Constructs a raw comprehension with the specifed arguments. A comprehension is raw as long as it has not been translated into a meaningful expression. Translation will happen automatically as soon as the meaning expresssion is needed.

Method Detail

setNoLetWrapping

public final Comprehension setNoLetWrapping()

tables

public final Tables tables()

operation

public final Expression operation()

identity

public final Expression identity()

copy

public final Expression copy()

Description copied from class: Expression

Returns a deep copy of this expression. The types are not not copied. NB: This is a convenience for building expressions that should be used exclusively before any processing (in particular sanitizing), is done on this expression.

Specified by:

copy in class Expression

typedCopy

public final Expression typedCopy()

Description copied from class: Expression

Returns a deep copy of this expression this and all its subexpressions share the same type as their copy's counterparts. NB: This is a convenience for building expressions that should be used exclusively before any processing (in particular sanitizing), is done on this expression.

Specified by:

typedCopy in class Expression

numberOfSubexpressions

public final int numberOfSubexpressions()

Description copied from class: Expression

Returns the number of subexpressions

Overrides:

numberOfSubexpressions in class Expression

subexpression

public final Expression subexpression(int n)
                               throws NoSuchSubexpressionException

Description copied from class: Expression

Returns the n-th subexpression of this expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException

Overrides:

subexpression in class Expression

Throws:

NoSuchSubexpressionException

setSubexpression

public final Expression setSubexpression(int n,
                          Expression expression)
                                  throws NoSuchSubexpressionException

Description copied from class: Expression

Returns this expression after setting its n-th subexpression to the specified expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException

Overrides:

setSubexpression in class Expression

Throws:

NoSuchSubexpressionException

sanitizeNames

public final Expression sanitizeNames(ParameterStack parameters)

Description copied from class: Expression

This method returns the actual expression corresponding to this one after eliminating all the Dummy expressions that occur in it where names where read. It takes as an argument the stack of parameters it encounters along the way of visiting all its components. A ParameterStack is simply a Stack of Parameter objects along with a method to retrieve the latest one with a given name.

Overrides:

sanitizeNames in class Expression

sanitizeSorts

public final void sanitizeSorts(Enclosure enclosure)

Description copied from class: Expression

This method walks down the expression gathering information relating each Local object to the Scope containing the corresponding Parameter in its array of formal parameters. It takes as an argument an Enclosure, which is a Stack containing all Scopes encountered along the way, equipped with a method to compute all the information necessary in computing the local's offset.

Overrides:

sanitizeSorts in class Expression

substitute

public Expression substitute(java.util.HashMap substitution)

Returns the comprehension obtained after applying the specified substitution to the subexpressions of this. If this comprehension is already translated, this simply amounts to setting the construct to the substituted construct. If this is a raw comprehension, care must be taken to proceed from left to right over the qualifiers and preventing generator variables from being substituted inside expressions to their right (including the main expression of the comprehension).

Overrides:

substitute in class Expression

setCheckedType

public final void setCheckedType()

Description copied from class: Expression

This method sets the final unambiguously checked type of this expression, possibly along with other final information that may be needed by the compiler for generating code.

Specified by:

setCheckedType in class Expression

typeCheck

public final void typeCheck(TypeChecker typeChecker)
                     throws TypingErrorException

Description copied from class: Expression

This method type-checks this expression in the context of the specified TypeChecker.

Specified by:

typeCheck in class Expression

Throws:

TypingErrorException

compile

public final void compile(Compiler compiler)

Description copied from class: Expression

This method compiles this expression in the context of the specified Compiler.

Specified by:

compile in class Expression

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object