org.extex.unit.tex.info
Class Show

java.lang.Object
  org.extex.interpreter.type.AbstractCode
      org.extex.unit.tex.info.Show

All Implemented Interfaces:

java.io.Serializable, LogEnabled, Code

Direct Known Subclasses:

Meaning

public class Show
extends AbstractCode
implements LogEnabled

This class provides an implementation for the primitive \show.

The Primitive \show

The primitive \show consumes the following token and prints the definition of the token to the output stream an into the log file.

• If the token is a control sequence or active character and it is undefined then it is reported as undefined.
• If the token is a control sequence or active character and it is a primitive then it is reported with the original name of the primitive. This applies even if is redefined with \let to another name.
• If the token is a control sequence or active character and it is a macro then it is reported with the pattern and expansion text.
• Otherwise the long descriptive form of the token is reported.

Syntax

The formal description of this primitive is the following:

    ⟨show⟩
       → \show ⟨token⟩ 

Examples

Examples:

    \show\abc
    > \abc=undefined
  

    \show \def
    > \def=\def.
  

    \let\xxx=\def\show \xxx
    > \xxx=\def.
  

    \def\m{abc}\show \m
    > \m=macro:
    ->abc.
  

    \show a
    > the letter a.
  

Version:

$Revision: 4770 $

Author:

Gerd Neugebauer

See Also:

Serialized Form

Field Summary

protected static long

serialVersionUID The constant serialVersionUID contains the id for serialization.

Constructor Summary

Show(CodeToken token)
Creates a new object.

Method Summary

void	enableLogging(java.util.logging.Logger log) Setter for the logger.
void	execute(Flags prefix, Context context, TokenSource source, Typesetter typesetter) This method takes the first token and executes it.
protected Tokens	meaning(Token t, Context context) Get the descriptions of a token as token list.

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

Show

public Show(CodeToken token)

Creates a new object.

Parameters:

token - the initial token for the primitive

Method Detail

enableLogging

public void enableLogging(java.util.logging.Logger log)

Setter for the logger.

Specified by:

enableLogging in interface LogEnabled

Parameters:

log - the logger to use

See Also:

LogEnabled.enableLogging( java.util.logging.Logger)

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:

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

meaning

protected Tokens meaning(Token t,
                         Context context)
                  throws HelpingException

Get the descriptions of a token as token list.

Parameters:

t - the token to describe

context - the interpreter context

Returns:

the token list describing the token

Throws:

HelpingException - in case of an error