jminusminus

Class JExpression

java.lang.Object

jminusminus.JAST

jminusminus.JStatement

jminusminus.JExpression

Direct Known Subclasses:

JArrayExpression, JArrayInitializer, JBinaryExpression, JCastOp, JFieldSelection, JInstanceOfOp, JLiteralChar, JLiteralFalse, JLiteralInt, JLiteralNull, JLiteralString, JLiteralTrue, JMessageExpression, JNewArrayOp, JNewOp, JSuper, JSuperConstruction, JThis, JThisConstruction, JUnaryExpression, JVariable, JWildExpression

abstract class JExpression
extends JStatement

The AST node for an expression. The syntax says all expressions are statements, but a semantic check throws some (those without a side-effect) out. Every expression has a type and a flag saying whether or not it's a statement-expression.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	isStatementExpression Whether or not this expression is a statement.
protected Type	type Expression type.

Fields inherited from class jminusminus.JAST

compilationUnit, line

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JExpression(int line) Construct an AST node for an expression given its line number.

Method Summary

Methods

Modifier and Type	Method and Description
abstract JExpression	analyze(Context context) The analysis of any JExpression returns a JExpression.
void	codegen(CLEmitter output, String targetLabel, boolean onTrue) Perform (short-circuit) code generation for a boolean expression, given the code emitter, a target label, and whether we branch to that label on true or on false.
boolean	isStatementExpression() Is this a statementRxpression?
Type	type() Return the expression type.

Methods inherited from class jminusminus.JAST

codegen, line, partialCodegen, writeToStdOut

Methods inherited from class java.lang.Object

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

Field Detail

type

protected Type type

Expression type.

isStatementExpression

protected boolean isStatementExpression

Whether or not this expression is a statement.

Constructor Detail

JExpression

protected JExpression(int line)

Construct an AST node for an expression given its line number.

Parameters:

line - line in which the expression occurs in the source file.

Method Detail

type

public Type type()

Return the expression type.

Returns:

the expression type.

isStatementExpression

public boolean isStatementExpression()

Is this a statementRxpression?

Returns:

whether or not this is being used as a statement.

analyze

public abstract JExpression analyze(Context context)

The analysis of any JExpression returns a JExpression. That's all this (re-)declaration of analyze() says.

Specified by:

analyze in class JAST

Parameters:

context - context in which names are resolved.

Returns:

the analyzed (and possibly rewritten) AST subtree.

codegen

public void codegen(CLEmitter output,
           String targetLabel,
           boolean onTrue)

Perform (short-circuit) code generation for a boolean expression, given the code emitter, a target label, and whether we branch to that label on true or on false.

Parameters:

output - the code emitter (basically an abstraction for producing the .class file).

targetLabel - the label to which we should branch.

onTrue - do we branch on true?