org.extex.unit.tex.hyphen
Class Discretionary

java.lang.Object
  org.extex.interpreter.type.AbstractCode
      org.extex.unit.tex.hyphen.Discretionary

All Implemented Interfaces:

java.io.Serializable, Code

public class Discretionary
extends AbstractCode

This class provides an implementation for the primitive \discretionary.

The Primitive \discretionary

The primitive \discretionary can be used to insert an optional break point into the paragraph. The optional break point consists of three parts. The first part is inserted into the paragraph if no line breaking happens at this position. In case that the line breaking chooses this place for a line break then the second part of the discretionary is inserted at the end of the current line and the third part is inserted at the beginning of the next line.

The three parts are given as three sequences of characters in braces. It may be composed of characters, ligatures, and rules only.

In math mode the third part is forced to be empty.

Syntax

The formal description of this primitive is the following:

    ⟨discretionary⟩
      → \discretionary{⟨pre⟩}{⟨post⟩}{⟨nobreak⟩}  

Examples

    \discretionary{f-}{fi}{ffi}
    \discretionary{-}{}{}  

Version:

$Revision: 4732 $

Author:

Gerd Neugebauer

See Also:

Serialized Form

Field Summary

protected static long

serialVersionUID The constant serialVersionUID contains the id for serialization.

Constructor Summary

Discretionary(CodeToken token)
Creates a new object.

Method Summary

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

Discretionary

public Discretionary(CodeToken token)

Creates a new object.

Parameters:

token - the initial token for the primitive

Method Detail

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)