jminusminus

Class JPlusOp

java.lang.Object

jminusminus.JAST

jminusminus.JStatement

jminusminus.JExpression

jminusminus.JBinaryExpression

jminusminus.JPlusOp

 class JPlusOp
extends JBinaryExpression

The AST node for a plus (+) expression. In j--, as in Java, + is overloaded to denote addition for numbers and concatenation for Strings.

Field Summary

Fields inherited from class jminusminus.JBinaryExpression

lhs, operator, rhs

Fields inherited from class jminusminus.JExpression

isStatementExpression, type

Fields inherited from class jminusminus.JAST

compilationUnit, line

Constructor Summary

Constructors

Constructor and Description
JPlusOp(int line, JExpression lhs, JExpression rhs) Construct an AST node for an addition expression given its line number, and the lhs and rhs operands.

Method Summary

Methods

Modifier and Type	Method and Description
JExpression	analyze(Context context) Analysis involves first analyzing the operands.
void	codegen(CLEmitter output) Any string concatenation has been rewritten as a JStringConcatenationOp (in analyze()), so code generation here involves simply generating code for loading the operands onto the stack and then generating the appropriate add instruction.

Methods inherited from class jminusminus.JBinaryExpression

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

JPlusOp

public JPlusOp(int line,
       JExpression lhs,
       JExpression rhs)

Construct an AST node for an addition expression given its line number, and the lhs and rhs operands.

Parameters:

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

lhs - the lhs operand.

rhs - the rhs operand.

Method Detail

analyze

public JExpression analyze(Context context)

Analysis involves first analyzing the operands. If this is a string concatenation, we rewrite the subtree to make that explicit (and analyze that). Otherwise we check the types of the addition operands and compute the result type.

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)

Any string concatenation has been rewritten as a JStringConcatenationOp (in analyze()), so code generation here involves simply generating code for loading the operands onto the stack and then generating the appropriate add instruction.

Specified by:

codegen in class JAST

Parameters:

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