jflex

Class SemCheck

java.lang.Object

jflex.SemCheck

public final class SemCheck
extends Object

Performs simple semantic analysis on regular expressions.

Version:

JFlex 1.7.0-SNAPSHOT

Author:

Gerwin Klein

Constructor Summary

Constructors

Constructor and Description
SemCheck()

Method Summary

Methods

Modifier and Type	Method and Description
static void	check(RegExps rs, Macros m, File f) Performs semantic analysis for all expressions.
static boolean	isFiniteChoice(RegExp re) Returns true iff the expression is a finite choice of fixed length expressions.
static int	length(RegExp re) Returns length if expression has fixed length, -1 otherwise.
static boolean	maybeEmtpy(RegExp re) Checks if the expression potentially matches the empty string.

Methods inherited from class java.lang.Object

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

Constructor Detail

SemCheck

public SemCheck()

Method Detail

check

public static void check(RegExps rs,
         Macros m,
         File f)

Performs semantic analysis for all expressions. Currently checks for empty expressions only.

Parameters:

rs - the reg exps to be checked

m - the macro table (in expanded form)

f - the spec file containing the rules

maybeEmtpy

public static boolean maybeEmtpy(RegExp re)

Checks if the expression potentially matches the empty string.

length

public static int length(RegExp re)

Returns length if expression has fixed length, -1 otherwise. Negation operators are treated as always variable length.

isFiniteChoice

public static boolean isFiniteChoice(RegExp re)

Returns true iff the expression is a finite choice of fixed length expressions. Negation operators are treated as always variable length.