jminusminus

Class JStringConcatenationOp

java.lang.Object

jminusminus.JAST

jminusminus.JStatement

jminusminus.JExpression

jminusminus.JBinaryExpression

jminusminus.JStringConcatenationOp

 class JStringConcatenationOp
extends JBinaryExpression

The AST node for a string concatenation operation. Nodes of this type are not produced by the parser but by analysis of a + operation where the arguments are strings. Such operations are rewritten to be string concatenation operations.

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
JStringConcatenationOp(int line, JExpression lhs, JExpression rhs) Construct an AST node for a string concatenation 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 is simple here.
void	codegen(CLEmitter output) Code generation generates code for creating a StringBuilder atop the runtime stack, appending the operands (which might contain nested concatenations; these are handled by cascadingCodegen()), and then for converting the StringBuilder to a String.
(package private) void	nestedCodegen(CLEmitter output) Like a codegen() but we needn't (and shouldn't) create a StringBuilder nor convert the result to a String, as that will be done in a parent.

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

JStringConcatenationOp

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

Construct an AST node for a string concatenation expression given its line number, and the lhs and rhs operands. An expression of this sort is created during the analysis of a (overloaded) + operation (and not by the Parser).

Parameters:

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

lhs - lhs operand.

rhs - rhs operand.

Method Detail

analyze

public JExpression analyze(Context context)

Analysis is simple here. The operands have already been analyzed (in JPlusOp) so we simply set 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)

Code generation generates code for creating a StringBuilder atop the runtime stack, appending the operands (which might contain nested concatenations; these are handled by cascadingCodegen()), and then for converting the StringBuilder to a String.

Specified by:

codegen in class JAST

Parameters:

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

nestedCodegen

void nestedCodegen(CLEmitter output)

Like a codegen() but we needn't (and shouldn't) create a StringBuilder nor convert the result to a String, as that will be done in a parent.

Parameters:

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