jflex

Class Macros

java.lang.Object

jflex.Macros

public final class Macros
extends Object

Symbol table and expander for macros. Maps macros to their (expanded) definitions, detects cycles and unused macros.

Version:

JFlex 1.7.0-SNAPSHOT

Author:

Gerwin Klein

Constructor Summary

Constructors

Constructor and Description
Macros() Creates a new macro expander.

Method Summary

Methods

Modifier and Type	Method and Description
void	expand() Expands all stored macros, so that getDefinition always returns a defintion that doesn't contain any macro usages.
RegExp	getDefinition(String name) Fetches the definition of the macro with the specified name,
boolean	insert(String name, RegExp definition) Stores a new macro and its definition.
boolean	isUsed(String name) Tests if a macro has been used.
boolean	markUsed(String name) Marks a makro as used.
List<String>	unused() Returns all unused macros.

Methods inherited from class java.lang.Object

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

Constructor Detail

Macros

public Macros()

Creates a new macro expander.

Method Detail

insert

public boolean insert(String name,
             RegExp definition)

Stores a new macro and its definition.

Parameters:

name - the name of the new macro

definition - the definition of the new macro

Returns:

true, iff the macro name has not been stored before.

markUsed

public boolean markUsed(String name)

Marks a makro as used.

Returns:

true, iff the macro name has been stored before.

isUsed

public boolean isUsed(String name)

Tests if a macro has been used.

Returns:

true, iff the macro has been used in a regular expression.

unused

public List<String> unused()

Returns all unused macros.

Returns:

the macro names that have not been used.

getDefinition

public RegExp getDefinition(String name)

Fetches the definition of the macro with the specified name,

The definition will either be the same as stored (expand() not called), or an equivalent one, that doesn't contain any macro usages (expand() called before).

Parameters:

name - the name of the macro

Returns:

the definition of the macro, null if no macro with the specified name has been stored.

See Also:

expand()

expand

public void expand()
            throws MacroException

Expands all stored macros, so that getDefinition always returns a defintion that doesn't contain any macro usages.

Throws:

MacroException - if there is a cycle in the macro usage graph.