org.extex.unit.base.register.font
Class NullfontPrimitive

java.lang.Object
  org.extex.interpreter.type.AbstractCode
      org.extex.unit.base.register.font.NullfontPrimitive

All Implemented Interfaces:

java.io.Serializable, Code, ComparableCode, FontConvertible

public class NullfontPrimitive
extends AbstractCode
implements FontConvertible, ComparableCode

This class provides an implementation for the primitive \nullfont.

The Primitive \nullfont

The primitive \nullfont provides access to an internal font contain no characters at all. Thus any attempt to produce a typeset output will not succeed. Nevertheless the font dimens can be read and written freely.

Syntax

The formal description of this primitive is the following:

    ⟨nullfont⟩
      → \nullfont  

Examples

    \font123=\nullfont  

The

\nullfont produces the primitive name \nullfont when applied to \the or \showthe.

Version:

$Revision:4431 $

Author:

Gerd Neugebauer

See Also:

Serialized Form

Field Summary

protected static long

serialVersionUID The constant serialVersionUID contains the id for serialization.

Constructor Summary

NullfontPrimitive(CodeToken token)
Creates a new object.

Method Summary

boolean	compare(Token token, Context context) Compare the code with some other code.
Font	convertFont(Context context, TokenSource source, Typesetter typesetter) Convert some primitive value into a font.
void	execute(Flags prefix, Context context, TokenSource source, Typesetter typesetter) This method takes the first token and executes it. The result is placed on the stack. This operation might have side effects. To execute a token it might be necessary to consume further tokens.

Methods inherited from class org.extex.interpreter.type.AbstractCode

getLocalizer, getName, getToken, isIf, isOuter, readResolve, toString, toText, toText

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

protected static final long serialVersionUID

The constant serialVersionUID contains the id for serialization.

See Also:

Constant Field Values

Constructor Detail

NullfontPrimitive

public NullfontPrimitive(CodeToken token)

Creates a new object.

Parameters:

token - the initial token for the primitive

Method Detail

compare

public boolean compare(Token token,
                       Context context)
                throws HelpingException

Compare the code with some other code.

Specified by:

compare in interface ComparableCode

Parameters:

token - the token to compare to

context - the interpreter context

Returns:

true iff the code is equivalent according to the semantics of \ifx

Throws:

HelpingException - in case of an error

See Also:

ComparableCode.compare( org.extex.scanner.type.token.Token, org.extex.interpreter.context.Context)

convertFont

public Font convertFont(Context context,
                        TokenSource source,
                        Typesetter typesetter)
                 throws HelpingException,
                        TypesetterException

Convert some primitive value into a font.

Specified by:

convertFont in interface FontConvertible

Parameters:

context - the interpreter context

source - the source for new tokens

typesetter - the typesetter

Returns:

the converted value

Throws:

HelpingException - in case of an error

TypesetterException - in case of an error in the typesetter

See Also:

FontConvertible.convertFont( org.extex.interpreter.context.Context, org.extex.interpreter.TokenSource, org.extex.typesetter.Typesetter)

execute

public void execute(Flags prefix,
                    Context context,
                    TokenSource source,
                    Typesetter typesetter)
             throws HelpingException,
                    TypesetterException

This method takes the first token and executes it. The result is placed on the stack. This operation might have side effects. To execute a token it might be necessary to consume further tokens.

Specified by:

execute in interface Code

Overrides:

execute in class AbstractCode

Parameters:

prefix - the prefix controlling the execution

context - the interpreter context

source - the token source

typesetter - the typesetter

Throws:

HelpingException - in case of an error

TypesetterException - in case of an error in the typesetter

See Also:

Code.execute( org.extex.interpreter.Flags, org.extex.interpreter.context.Context, org.extex.interpreter.TokenSource, org.extex.typesetter.Typesetter)