com.google.gwt.dev.js

Class JsDuplicateCaseFolder

java.lang.Object

com.google.gwt.dev.js.JsDuplicateCaseFolder

public class JsDuplicateCaseFolder
extends Object

Combine case labels with identical bodies. Case bodies that may fall through to the following case label and case bodies following a possible fallthrough are left undisturbed. For example, consider the following input:

 switch (x) {
   case 0: y = 17; break;
   case 1: if (z == 0) { y = 18; break; } else { y = 19 } // fallthrough else
   case 2: return 22;
   case 3: if (z == 0) { y = 18; break; } else { y = 19 } // fallthrough else
   case 4: y = 17; break;
   case 5: y = 17; break;
   case 6: return 22;
 }
 

This will be transformed into:

 switch (x) {
   case 0: y = 17; break;
   case 1: if (z == 0) { y = 18; break; } else { y = 19 }
   case 6: case 2: return 22;
   case 3: if (z == 0) { y = 18; break; } else { y = 19 }
   case 5: case 4: y = 17; break;
 }

 

 Cases (2, 6) and (4, 5) have been coalesced.  Note that case 0 has not been
 combined with cases 4 and 5 since case 4 cannot be moved due to the potential
 fallthrough from case 3, and we currently only coalesce a given cases with a
 preceding case and so cannot move case 0 downward.

 Although this pattern is unlikely to occur frequently in hand-written code,
 it can account for a significant amount of space in generated code.

Constructor Summary

Constructors

Constructor and Description
JsDuplicateCaseFolder()

Method Summary

Modifier and Type	Method and Description
static boolean	exec(JsProgram program)

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

JsDuplicateCaseFolder

public JsDuplicateCaseFolder()

Method Detail

exec

public static boolean exec(JsProgram program)