net.sourceforge.czt.parser.z
Class OperatorScanner

java.lang.Object
  net.sourceforge.czt.parser.z.OperatorScanner

All Implemented Interfaces:

net.sourceforge.czt.java_cup.runtime.Scanner

public class OperatorScanner
extends java.lang.Object
implements net.sourceforge.czt.java_cup.runtime.Scanner

This is an operator lexer (part of context-sensitive lexis) for Z specifications in unicode format.

According to the ISO Standard for Z, the lexis for Z specifications consists of two phases: the context-free lexis and the context-sensitive lexis. This class is an implementation of sections 7.4.4 and 7.5 of the ISO Z standard, which describes the context-sensitive lexis.

This class transforms a stream of tokens into another stream of tokens. It translates words (DECORWORD or DECLWORD tokens) into operator tokens like L, I, etc. There are two cases in which a transformation to operator tokens is not performed:

• When parsing an operator template, so that an operator can be re-used (see section 8.3).
• When parsing a section header, so that section names can be operator names (see section 8.4).

The transformation into operator tokens requires a lookup in an operator table, which must be set appropriately before the lookup is performed. This is usually done by the parser who updates the operator table while parsing. This is not standard conforming since the operator table gets updated when an operator template is parsed while the standard requires that the scope of the associations between words and operator tokens is the whole of the section in which the operator template appears (not just from the operator template onwards).

Method Summary

OpTable	getOperatorTable()
protected net.sourceforge.czt.java_cup.runtime.Symbol	localLookup(net.sourceforge.czt.java_cup.runtime.Symbol symbol) Lookup the value of this symbol
net.sourceforge.czt.java_cup.runtime.Symbol	next_token()
void	setOperatorTable(OpTable table)

Methods inherited from class java.lang.Object

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

Method Detail

getOperatorTable

public OpTable getOperatorTable()

setOperatorTable

public void setOperatorTable(OpTable table)

next_token

public net.sourceforge.czt.java_cup.runtime.Symbol next_token()
                                                       throws java.lang.Exception

Specified by:

next_token in interface net.sourceforge.czt.java_cup.runtime.Scanner

Throws:

java.lang.Exception

localLookup

protected net.sourceforge.czt.java_cup.runtime.Symbol localLookup(net.sourceforge.czt.java_cup.runtime.Symbol symbol)

Lookup the value of this symbol