org.stekikun.dolmen.debug

Interface Derivation.Displayer

Enclosing class:

Derivation

public static interface Derivation.Displayer

This interface is used by Derivation.append(Displayer, Appendable) to allow the display of Derivation objects to be customized. The interface defines several callback routines which are called by the displaying engine and can be used to produce whatever structured output one wants from a derivation tree.

It is guaranteed that the methods in Derivation.Displayer are called in a sequence X that follows these inductive rules:

• either X is a single call to terminal(Appendable, short);
• or X is a call to production(Appendable, short, short) followed by either of:
  • nothing if the production was empty;
  • a call to enter(Appendable) followed by any non-negative number of X, each followed by next(Appendable), ending with one X and a call to leave(Appendable).

Author:

Stéphane Lescuyer

Field Summary

Fields

Modifier and Type	Field and Description
static Derivation.Displayer	RAW An implementation of Derivation.Displayer which displays the derivations exactly as they are stored

Method Summary

Modifier and Type	Method and Description
void	enter(Appendable app) Enters the sub-derivations of a production
void	leave(Appendable app) Completes the sub-derivations of a production
void	next(Appendable app) Separates two sub-derivations of a production
static Derivation.Displayer	ofGrammar(Grammar grammar, int initialIndent) The result is printed as if starting at column initialIndent.
void	production(Appendable app, short rule, short prod) Displays a production for the given rule and production ordinals
void	terminal(Appendable app, short token) Displays a terminal with the given token ordinal

Field Detail

RAW

static final Derivation.Displayer RAW

An implementation of Derivation.Displayer which displays the derivations exactly as they are stored

Method Detail

terminal

void terminal(Appendable app,
              short token)
       throws IOException

Displays a terminal with the given token ordinal

Parameters:

app -

token -

Throws:

IOException

production

void production(Appendable app,
                short rule,
                short prod)
         throws IOException

Displays a production for the given rule and production ordinals

Parameters:

app -

rule -

prod -

Throws:

IOException

enter

void enter(Appendable app)
    throws IOException

Enters the sub-derivations of a production

Parameters:

app -

Throws:

IOException

next

void next(Appendable app)
   throws IOException

Separates two sub-derivations of a production

Parameters:

app -

Throws:

IOException

leave

void leave(Appendable app)
    throws IOException

Completes the sub-derivations of a production

Parameters:

app -

Throws:

IOException

ofGrammar

static Derivation.Displayer ofGrammar(Grammar grammar,
                                      int initialIndent)

The result is printed as if starting at column initialIndent.

Parameters:

grammar -

initialIndent -

Returns:

an implementation of Derivation.Displayer which pretty-prints the derivation by interpreting it with respect to the given grammar