Package software.amazon.smithy.rulesengine.language.syntax.expressions

Class Expression

java.lang.Object

software.amazon.smithy.rulesengine.language.syntax.SyntaxElement

software.amazon.smithy.rulesengine.language.syntax.expressions.Expression

All Implemented Interfaces:

FromSourceLocation, ToNode, TypeCheck, ToCondition, ToExpression

Direct Known Subclasses:

LibraryFunction, Literal, Reference

public abstract class Expression
extends SyntaxElement
implements FromSourceLocation, ToNode, TypeCheck

A dynamically computed expression.

Expressions are the fundamental building block of the rule language.

Constructor Summary

Constructors

Constructor	Description
Expression(SourceLocation sourceLocation)

Method Summary

Modifier and Type	Method	Description
abstract <R> R	accept(ExpressionVisitor<R> visitor)	Invoke the ExpressionVisitor functions for this expression.
abstract boolean	equals(Object obj)
static Expression	fromNode(Node node)	Constructs an expression from the provided Node.
static Literal	getLiteral(StringNode node)	Constructs a Literal from the given StringNode.
static Reference	getReference(Identifier name, FromSourceLocation context)	Constructs a Reference for the given Identifier at the given location.
SourceLocation	getSourceLocation()	Gets the source location of a value.
abstract int	hashCode()
static Literal	of(boolean value)
static Literal	of(int value)	Construct an integer literal for the given value, and returns it as an expression.
static Literal	of(String value)	Constructs a string literal for the given values.
static Expression	parseShortform(String shortForm, FromSourceLocation context)	Parse a value from a "short form" used within a template.
Condition.Builder	toConditionBuilder()	Convert this into a condition builder for compositional use.
Expression	toExpression()	Convert this into an expression.
Type	type()	Returns the type for this expression, throws a runtime exception if typeCheck has not been invoked.
Type	typeCheck(Scope<Type> scope)	Checks whether the given types within a scope satisfy the constraints.
protected abstract Type	typeCheckLocal(Scope<Type> scope)

Methods inherited from class software.amazon.smithy.rulesengine.language.syntax.SyntaxElement

booleanEqual, getAttr, getAttr, isSet, isValidHostLabel, not, parseUrl, stringEqual, substring, template

Methods inherited from class java.lang.Object

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

Methods inherited from interface software.amazon.smithy.rulesengine.language.syntax.ToCondition

toCondition, toCondition

Methods inherited from interface software.amazon.smithy.model.node.ToNode

toNode

Constructor Details

Expression

public Expression(SourceLocation sourceLocation)

Method Details

of

public static Literal of(boolean value)

of

public static Literal of(int value)

Construct an integer literal for the given value, and returns it as an expression.

Parameters:

value - the integer value.

Returns:

the integer value as a literal expression.

of

public static Literal of(String value)

Constructs a string literal for the given values.

Parameters:

value - the string value.

Returns:

the string value as a literal.

fromNode

public static Expression fromNode(Node node)

Constructs an expression from the provided Node.

Parameters:

node - the node to construct the expression from.

Returns:

the expression.

parseShortform

public static Expression parseShortform(String shortForm,
 FromSourceLocation context)

Parse a value from a "short form" used within a template.

Parameters:

shortForm - the shortform value

Returns:

the parsed expression

getReference

public static Reference getReference(Identifier name,
 FromSourceLocation context)

Constructs a Reference for the given Identifier at the given location.

Parameters:

name - the referenced identifier.

context - the source location.

Returns:

the reference.

getLiteral

public static Literal getLiteral(StringNode node)

Constructs a Literal from the given StringNode.

Parameters:

node - the node to construct the literal from.

Returns:

the string node as a literal.

accept

public abstract <R> R accept(ExpressionVisitor<R> visitor)

Invoke the ExpressionVisitor functions for this expression.

Type Parameters:

R - the visitor return type.

Parameters:

visitor - the visitor to be invoked.

Returns:

the return value of the visitor.

typeCheckLocal

protected abstract Type typeCheckLocal(Scope<Type> scope)
                                throws InnerParseError

Throws:

InnerParseError

type

public Type type()

Returns the type for this expression, throws a runtime exception if typeCheck has not been invoked.

Returns:

the type.

toConditionBuilder

public Condition.Builder toConditionBuilder()

Description copied from interface: ToCondition

Convert this into a condition builder for compositional use.

Specified by:

toConditionBuilder in interface ToCondition

Returns:

the condition builder.

toExpression

public Expression toExpression()

Description copied from interface: ToExpression

Convert this into an expression.

Specified by:

toExpression in interface ToExpression

Returns:

the expression.

hashCode

public abstract int hashCode()

Overrides:

hashCode in class Object

equals

public abstract boolean equals(Object obj)

Overrides:

equals in class Object

getSourceLocation

public SourceLocation getSourceLocation()

Description copied from interface: FromSourceLocation

Gets the source location of a value.

Specified by:

getSourceLocation in interface FromSourceLocation

Returns:

Returns the source location of the value.

typeCheck

public Type typeCheck(Scope<Type> scope)

Description copied from interface: TypeCheck

Checks whether the given types within a scope satisfy the constraints.

Specified by:

typeCheck in interface TypeCheck

Parameters:

scope - the scope to evaluate.

Returns:

the type validated by the scope check.