xrel.analyzer
Class PatternMatching

java.lang.Object
  |
  +--xrel.analyzer.PatternMatching

All Implemented Interfaces:

SymElementKind

public class PatternMatching

extends java.lang.Object

implements SymElementKind

Contains the run-time pattern matching algorithm. The method matchWith calls the algorithm for pattern matching.

N.B.:

• this is a static class so you will never need to allocate an object for this class

Author:

Fabrizio Bisi

Fields inherited from interface xrel.parser.SymElementKind

EXPRESSION, LABEL, PATTERN, S_EXPRESSIONS, S_LABELS, S_PATTERNS, S_TYPES, S_VARIABLES, TYPE, UNDEFINED, VARIABLE

Constructor Summary

PatternMatching()

Method Summary

static SimpleNode	getEvaluation() Evaluates the output value.
static int	matchWith(SymTable st, SimpleNode value, java.io.PrintStream out, boolean debug) The main method of this class.

Methods inherited from class java.lang.Object

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

Constructor Detail

PatternMatching

public PatternMatching()

Method Detail

matchWith

public static int matchWith(SymTable st,
                            SimpleNode value,
                            java.io.PrintStream out,
                            boolean debug)

The main method of this class. It tries to match a value passed as argument against the patterns of the program. If the match is successful and a typeswitch instruction appears in the code the variable matchingClause contains the number of the clause that matched with the value.

Parameters:

value - the value to check. The patterns are passed throughout the symbol table.

out - where to print out debug information

debug - if true print out debug information

Returns:

the matching clause or -1

getEvaluation

public static SimpleNode getEvaluation()

Evaluates the output value. Call only after executing the main algorithm.

Returns:

the output value