jminusminus

Class JPostDecrementOp

java.lang.Object

jminusminus.JAST

jminusminus.JStatement

jminusminus.JExpression

jminusminus.JUnaryExpression

jminusminus.JPostDecrementOp

 class JPostDecrementOp
extends JUnaryExpression

The AST node for an expr--.

Field Summary

Fields inherited from class jminusminus.JUnaryExpression

arg

Fields inherited from class jminusminus.JExpression

isStatementExpression, type

Fields inherited from class jminusminus.JAST

compilationUnit, line

Constructor Summary

Constructors

Constructor and Description
JPostDecrementOp(int line, JExpression arg) Construct an AST node for an expr-- expression given its line number, and the operand.

Method Summary

Methods

Modifier and Type	Method and Description
JExpression	analyze(Context context) Analyze the operand as a lhs (since there is a side effect), check types and determine the type of the result.
void	codegen(CLEmitter output) In generating code for a post-decrement operation, we treat simple variable (JVariable) operands specially since the JVM has an increment instruction.

Methods inherited from class jminusminus.JUnaryExpression

writeToStdOut

Methods inherited from class jminusminus.JExpression

codegen, isStatementExpression, type

Methods inherited from class jminusminus.JAST

line, partialCodegen

Methods inherited from class java.lang.Object

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

Constructor Detail

JPostDecrementOp

public JPostDecrementOp(int line,
                JExpression arg)

Construct an AST node for an expr-- expression given its line number, and the operand.

Parameters:

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

arg - the operand.

Method Detail

analyze

public JExpression analyze(Context context)

Analyze the operand as a lhs (since there is a side effect), check types and determine the type of the result.

Specified by:

analyze in class JExpression

Parameters:

context - context in which names are resolved.

Returns:

the analyzed (and possibly rewritten) AST subtree.

codegen

public void codegen(CLEmitter output)

In generating code for a post-decrement operation, we treat simple variable (JVariable) operands specially since the JVM has an increment instruction. Otherwise, we rely on the JLhs code generation support for generating the proper code. Notice that we distinguish between expressions that are statement expressions and those that are not; we insure the proper value (before the decrement) is left atop the stack in the latter case.

Specified by:

codegen in class JAST

Parameters:

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