Class PrecedenceTest

  extended by soot.grimp.PrecedenceTest

public class PrecedenceTest
extends Object

Provides static helper methods to indicate if parenthesization is required. If your sub-expression has strictly higher precedence than you, then no brackets are required: 2 + (4 * 5) = 2 + 4 * 5 is unambiguous, because * has precedence 800 and + has precedence 700. If your subexpression has lower precedence than you, then brackets are required; otherwise you will bind to your grandchild instead of the subexpression. 2 * (4 + 5) without brackets would mean (2 * 4) + 5. For a binary operation, if your left sub-expression has the same precedence as you, no brackets are needed, since binary operations are all left-associative. If your right sub-expression has the same precedence than you, then brackets are needed to reproduce the parse tree (otherwise, parsing will give e.g. (2 + 4) + 5 instead of the 2 + (4 + 5) that you had to start with.) This is OK for integer addition and subtraction, but not OK for floating point multiplication. To be safe, let's put the brackets on. For the high-precedence operations, I've assigned precedences of 950 to field reads and invoke expressions (.), as well as array reads ([]). I've assigned 850 to cast, newarray and newinvoke. The Dava DCmp?Expr precedences look fishy to me; I've assigned DLengthExpr a precedence of 950, because it looks like it should parse like a field read to me. Basically, the only time I can see that brackets should be required seems to occur when a cast or a newarray occurs as a subexpression of an invoke or field read; hence 850 and 950. -PL

Constructor Summary
Method Summary
static boolean needsBrackets(ValueBox subExprBox, Value expr)
static boolean needsBracketsRight(ValueBox subExprBox, Value expr)
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public PrecedenceTest()
Method Detail


public static boolean needsBrackets(ValueBox subExprBox,
                                    Value expr)


public static boolean needsBracketsRight(ValueBox subExprBox,
                                         Value expr)