org.vishia.zbnf.ebnfConvert

Class EBNFconvert

java.lang.Object

org.vishia.zbnf.ebnfConvert.EBNFconvert

public class EBNFconvert
extends java.lang.Object

This class writes zbnf syntax from read EBNF.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.Map<java.lang.String,EBNFread.EBNFdef>	idx_cmpnDef All syntax components sorted with syntax symbol name.
static java.lang.String	sVersion Version, history and license.

Constructor Summary

Constructors

Constructor and Description
EBNFconvert()

Method Summary

Modifier and Type	Method and Description
private void	checkAllCmpn(EBNFread ebnf) Checks for identifier definition: If a EBNFdefinition is written as syntaxdefXYZ ::= <identifier> then the syntaxdef is added to the #identifiers.
private void	checkCmpn(EBNFread.EBNFdef ebnfCmpn)
(package private) void	checkExpr(EBNFread.EBNFexpr expr, EBNFread.EBNFdef cmpn, int recursive)
(package private) void	checkitem(EBNFread.EBNFitem item, EBNFread.EBNFdef cmpn, int recursive)
private void	checkRepetition(java.lang.Appendable wr, java.lang.String sCmpnBeforeRepeat, EBNFread.EBNFexpr expr, boolean bOnlyOneCmpn, int level) In EBNF a typical repetition is written like COMPONENT { SEPARATOR COMPONENT }.
void	convert(EBNFread ebnf, java.lang.Appendable wr) Invoked from a JZtxtcmd script.
private void	convertExpr(java.lang.Appendable wr, EBNFread.EBNFexpr expr, int level)
private java.lang.String	convertItem(java.lang.Appendable wr, java.lang.String sCmpnBeforeRepeat, EBNFread.EBNFitem item, EBNFread.EBNFdef inCmpn, boolean bOnlyOneCmpn, int level) Converts one item from the read EBNF.
private void	wrCmpnCall(java.lang.Appendable wr, java.lang.String sCmpn, boolean bOnlyOneCmpn, EBNFread.EBNFdef inCmpn) It writes a component call.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

sVersion

public static final java.lang.String sVersion

Version, history and license.

• 2019-05-14 Hartmut creation:

Copyright/Copyleft: For this source the LGPL Lesser General Public License, published by the Free Software Foundation is valid. It means:

1. You can use this source without any restriction for any desired purpose.
2. You can redistribute copies of this source to everybody.
3. Every user of this source, also the user of redistribute copies with or without payment, must accept this license for further using.
4. But the LPGL is not appropriate for a whole software product, if this source is only a part of them. It means, the user must publish this part of source, but don't need to publish the whole source of the own product.
5. You can study and modify (improve) this source for own using or for redistribution, but you have to license the modified sources likewise under this LGPL Lesser General Public License. You mustn't delete this Copyright/Copyleft inscription in this source file.

If you are intent to use this sources without publishing its usage, you can get a second license subscribing a special contract with the author.

See Also:

Constant Field Values

idx_cmpnDef

java.util.Map<java.lang.String,EBNFread.EBNFdef> idx_cmpnDef

All syntax components sorted with syntax symbol name.

Constructor Detail

EBNFconvert

public EBNFconvert()

Method Detail

convert

public void convert(EBNFread ebnf,
                    java.lang.Appendable wr)

Invoked from a JZtxtcmd script.

Parameters:

ebnf - parsed data

wr - FileWriter

checkAllCmpn

private void checkAllCmpn(EBNFread ebnf)

Checks for identifier definition: If a EBNFdefinition is written as

 syntaxdefXYZ ::= <identifier> 

then the syntaxdef is added to the #identifiers. On usage with

   ... syntaxdefXYZ ...

it is translated to

   ... <$?syntaxdefXYZ>

Parameters:

ebnf -

checkCmpn

private void checkCmpn(EBNFread.EBNFdef ebnfCmpn)

checkExpr

void checkExpr(EBNFread.EBNFexpr expr,
               EBNFread.EBNFdef cmpn,
               int recursive)

checkitem

void checkitem(EBNFread.EBNFitem item,
               EBNFread.EBNFdef cmpn,
               int recursive)

convertExpr

private void convertExpr(java.lang.Appendable wr,
                         EBNFread.EBNFexpr expr,
                         int level)
                  throws java.io.IOException

Throws:

java.io.IOException

convertItem

private java.lang.String convertItem(java.lang.Appendable wr,
                                     java.lang.String sCmpnBeforeRepeat,
                                     EBNFread.EBNFitem item,
                                     EBNFread.EBNFdef inCmpn,
                                     boolean bOnlyOneCmpn,
                                     int level)
                              throws java.io.IOException

Converts one item from the read EBNF. An item is defined as

EBNFitem::=
  '<*'?literal>'               ## 'literal'
| <""?literal>                 ## "literal"
| \<<*\>?comment>\>            ## 
| <$?cmpn> [? ::= ]            ##ident::= breaks the loop, it is a new definition.
| \[  \]      ## [ simple option ]
| \{  \}  ## { repetition }  Note: can be empty. 
| (  )   ##sub syntax with own structure
.   * 

• Special handling of component { ...syntax... component }:
  It should be written as { <component> ? ...syntax...}
  For that the component is not written but returned and checked for the next item if a repetition follows. If it is not so, the component is written with #wrCmpnCall(Appendable, String)-
• EBNFalt is a sub syntax of the item. It is converted with calling convertExpr(Appendable, org.vishia.zbnf.ebnfConvert.EBNFread.EBNFexpr, int).
• Elsewhere the simple ZBNF representation is written.

Parameters:

wr -

sCmpnBeforeRepeat - It is written as component like <?component> using #wrCmpnCall(Appendable, String) if this item is not a repetition. It is checked in #checkRepetition(Appendable, String, org.vishia.zbnf.ebnfConvert.EBNFread.EBNFexpr, int).

item -

level -

Returns:

null or a component name if a component call is detected.

Throws:

java.io.IOException

wrCmpnCall

private void wrCmpnCall(java.lang.Appendable wr,
                        java.lang.String sCmpn,
                        boolean bOnlyOneCmpn,
                        EBNFread.EBNFdef inCmpn)
                 throws java.io.IOException

It writes a component call. It is deferred for repetition check.

Parameters:

wr -

sCmpn -

Throws:

java.io.IOException

checkRepetition

private void checkRepetition(java.lang.Appendable wr,
                             java.lang.String sCmpnBeforeRepeat,
                             EBNFread.EBNFexpr expr,
                             boolean bOnlyOneCmpn,
                             int level)
                      throws java.io.IOException

In EBNF a typical repetition is written like

 COMPONENT { SEPARATOR COMPONENT }.

In Zbnf it is more simple, more clear and necessary to create data:

 { <COMPONENT> ? SEPARATOR }.

After ? it is the backward branch.
This routine tests whether the last item of expr is a Component call with the same component like given in sCmpnBeforeRepeat. Then it is such a typical kind of repetition with at least one occurence and separator.

Parameters:

wr -

sCmpnBeforeRepeat -

expr -

level -

Throws:

java.io.IOException