de.dante.extex.interpreter.primitives.register.box
Class Dp

java.lang.Object
  de.dante.extex.interpreter.type.AbstractCode
      de.dante.extex.interpreter.primitives.register.box.AbstractBox
          de.dante.extex.interpreter.primitives.register.box.Setbox
              de.dante.extex.interpreter.primitives.register.box.Dp

All Implemented Interfaces:

Code, CountConvertible, DimenConvertible, ExpandableCode, Localizable, java.io.Serializable, Theable

public class Dp

extends Setbox

implements java.io.Serializable, ExpandableCode, Theable, CountConvertible, DimenConvertible

This class provides an implementation for the primitive \dp.

The Primitive \dp

The primitive \dp refers to the depth of a box register. It can be used in various contexts.

Execution of the Primitive

If the primitive is used in a context it initiated an assignment to the actual depth of the box register. This has an effect only in the case that the box register is not void.

The formal description of this primitive is the following:

    ⟨dp⟩
      → ⟨optional prefix⟩ \dp ⟨box register name⟩ ⟨equals⟩ ⟨dimen⟩

    ⟨optional prefix⟩
      →
       |  \global ⟨optional prefix⟩  

Examples

    \dp42 = 12mm  

    \dp42 = \dimen3  

Expansion of the Primitive

In an expansion context the primitive results in the the current depth of the given box register. In case that the box register is empty the result is 0 pt.

Syntax

The formal description of this primitive is the following:

    \dp ⟨8-bit number⟩ 

Examples

    \dimen0 = \dp42  

    \the\dp42  

Conversion to a Count

The primitive is convertible into a count. It can be used wherever an integer quantity is expected.

Interaction with \the

The primitive \the can be applied to this primitive. In this case it results in a token list representing the value in points.

Version:

$Revision: 1.37 $

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

Dp

public Dp(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 Setbox

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

Parameters:

prefix - the prefix flags controlling the expansion

context - the interpreter context

source - the token source

typesetter - the typesetter

Throws:

InterpreterException - in case of an error

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)

the

public Tokens the(Context context,
                  TokenSource source,
                  Typesetter typesetter)
           throws InterpreterException

Description copied from interface: Theable

This method is the getter for the description of the primitive.

Specified by:

the in interface Theable

Parameters:

context - the interpreter context

source - the source for further tokens to qualify the request

typesetter - the typesetter to use

Returns:

the description of the primitive as list of Tokens

Throws:

InterpreterException - in case of an error

See Also:

Theable.the( de.dante.extex.interpreter.context.Context, de.dante.extex.interpreter.TokenSource, Typesetter)

convertCount

public long convertCount(Context context,
                         TokenSource source,
                         Typesetter typesetter)
                  throws InterpreterException

Description copied from interface: CountConvertible

This method converts a register into a count. It might be necessary to read further tokens to determine which value to use. For instance an additional register number might be required. In this case the additional arguments Context and TokenSource can be used.

Specified by:

convertCount in interface CountConvertible

Parameters:

context - the interpreter context

source - the source for new tokens

typesetter - the typesetter to use for conversion

Returns:

the converted value

Throws:

InterpreterException - in case of an error

See Also:

CountConvertible.convertCount( de.dante.extex.interpreter.context.Context, de.dante.extex.interpreter.TokenSource, Typesetter)

convertDimen

public long convertDimen(Context context,
                         TokenSource source,
                         Typesetter typesetter)
                  throws InterpreterException

Description copied from interface: DimenConvertible

This method converts a register into a dimen. It might be necessary to read further tokens to determine which value to use. For instance an additional register number might be required. In this case the additional arguments Context and TokenSource can be used. The return value is the length in scaled points.

Specified by:

convertDimen in interface DimenConvertible

Parameters:

context - the interpreter context

source - the source for new tokens

typesetter - the typesetter to use for conversion

Returns:

the converted value in sp

Throws:

InterpreterException - in case of an error

See Also:

DimenConvertible.convertDimen( de.dante.extex.interpreter.context.Context, de.dante.extex.interpreter.TokenSource, Typesetter)