de.dante.extex.interpreter.primitives.conditional
Class Ifcase

java.lang.Object
  de.dante.extex.interpreter.type.AbstractCode
      de.dante.extex.interpreter.primitives.conditional.AbstractIf
          de.dante.extex.interpreter.primitives.conditional.Ifcase

All Implemented Interfaces:

Code, ExpandableCode, Localizable, java.io.Serializable

public class Ifcase

extends AbstractIf

This class provides an implementation for the primitive \ifcase.

The Primitive \ifcase

The primitive \ifcase provides a conditional switch on a numeric value. The next tokens are used as a number. This number determines which branch to expand. The first branch follows the number immediately. This branch is associated to the number 0.

The primitive \or advances to the next branch. The primitive \else starts the else branch. The else branch is used if no other branch fits.

Syntax

    ⟨ifcase⟩
     → \ifcase ⟨number⟩  ⟨cases⟩ \fi

    ⟨cases⟩
     →
      |  ⟨branch text⟩ \else ⟨else text⟩
      |  ⟨branch text⟩ \or ⟨cases⟩  

Examples

    \ifcase\count0 a\or b\or c\else x\fi  

Version:

$Revision: 1.34 $

Author:

Gerd Neugebauer

See Also:

Serialized Form

serialVersionUID

protected static final long serialVersionUID

The constant serialVersionUID contains the id for serialization.

See Also:

Constant Field Values

OR

protected static final Ifcase.Tag OR

The constant OR contains the value indicating an \or.

ELSE

protected static final Ifcase.Tag ELSE

The constant ELSE contains the value indicating an \else.

FI

protected static final Ifcase.Tag FI

The constant FI contains the value indicating a \fi.

Ifcase

public Ifcase(java.lang.String name)

Creates a new object.

Parameters:

name - the name for debugging

execute

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

Description copied from interface: Code

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 AbstractIf

Throws:

InterpreterException

See Also:

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

expand

public void expand(Flags prefix,
                   Context context,
                   TokenSource source,
                   Typesetter typesetter)
            throws InterpreterException

Description copied from interface: ExpandableCode

This method takes the first token and expands it. The result is placed on the stack. This means that expandable code does one step of expansion and puts the result on the stack. To expand a token it might be necessary to consume further tokens.

Specified by:

expand in interface ExpandableCode

Overrides:

expand in class AbstractIf

Throws:

InterpreterException

See Also:

ExpandableCode.expand( de.dante.extex.interpreter.Flags, de.dante.extex.interpreter.context.Context, de.dante.extex.interpreter.TokenSource, de.dante.extex.typesetter.Typesetter)

conditional

protected boolean conditional(Context context,
                              TokenSource source,
                              Typesetter typesetter)

Description copied from class: AbstractIf

This method computes the boolean value of the conditional. If the result is true then the then branch is expanded and the else branch is skipped. Otherwise the then branch is skipped and the else branch is expanded.

Specified by:

conditional in class AbstractIf

Parameters:

context - the interpreter context

source - the source for new tokens

typesetter - the typesetter

Returns:

the boolean value

See Also:

AbstractIf.conditional( de.dante.extex.interpreter.context.Context, de.dante.extex.interpreter.TokenSource, de.dante.extex.typesetter.Typesetter)