Support of Different Character Sets with NATCONV.INI

The settings in the configuration file NATCONV.INI apply to the A format. For the U format, the ICU library is used.

This document describes how Natural supports different character sets. It covers the following topics:

Why is the Support of Different Character Sets Important?

The support of multiple languages with different character sets represents Natural's approach towards internationalization. It can help you when using:

  • upper-/lower-case translation of language-specific characters;

  • language-specific characters in Natural identifiers, object names and library names;

  • language-specific characters in an operand compared with a mask definition (see MASK Option in the Programming Guide).

How to Use Different Character Sets

All check, translation and classification tables used by Natural to support language-specific characters reside in the configuration file NATCONV.INI. By default, this file is located in Natural's etc directory.

You can modify NATCONV.INI to support local or application-specific character sets.

In a standard application, NATCONV.INI need not and should not be modified, because this could lead to serious inconsistencies, in particular if Natural objects and database data are already present.

Any modifications of NATCONV.INI should be well considered and carefully performed, otherwise problems might occur that are difficult to locate.

NATCONV.INI is subdivided in sections and subsections. The following sections are defined:

Section Description
CHARACTERSET-DEFINITION This section defines the name of the internal character set. The default is ISO8859_1.

If you choose a different character set, subsections for this character set must be contained in the sections described below.

CASE-TRANSLATION This section contains the tables required for the conversion from upper-case to lower-case which is performed when one of the following is specified: This conversion is done within the internal character set. If the internal character set is, for example, ISO8859_5, the following two subsections must be contained in this section:
  • [ISO8859_5->UPPER]

  • [ISO8859_5->LOWER]

IDENTIFIER-VALIDATION This section contains the tables required for the validation of identifiers (that is, user-defined variables in source programs), object names and library names. It contains a subsection for each defined internal character set.

The special characters "#" (for non-database variables), "+" (for application-independent variables), "@" (for SQL and Adabas null or length indicators) and "&" (for dynamic source generation) can be redefined in this section. In addition, the set of valid first and subsequent characters for identifiers, object names and library names can be modified.

When extending the set of valid characters for object names with values greater than x7f (decimal 127), the sorting sequence of the objects (for example, during a LIST * command) may not be in the numerical order.

CHARACTER-CLASSIFICATION This section contains the tables required for the classification of characters, which, for example, are used when evaluating the MASK option. It contains a subsection for each defined internal character set.

The section CHARACTERSET-DEFINITION and each subsection contain lines which describe how characters are to be converted and which characters are related with which attributes. These lines are represented as follows:

line         ::=  key = value 
key          ::=  name_key | range_key 
name_key     ::=  keyword{ CHARS } 
                    ISLOWER | ISUPPER | ISCNTRL | ISPRINT | ISPUNCT | 
                    ISGRAPH | ISSPACE 
range_key    ::=  hexnum | hexnum-hexnum 
value        ::=  val {, val } 
val          ::=  hexnum | hexnum-hexnum 
hexnum       ::=  xhexdigithexdigit | xhexdigithexdigit


  1. If the range_key variable is specified on the left-hand side, the number of values specified on the right-hand side must correspond to the number of values specified in the key range, unless only one value is specified on the right-hand side, which is then assigned to each element of the key range.
  2. When the name_key variable is specified on the left-hand side and the corresponding list of character codes does not fit in one line, it can be continued on the next line by specifying name_key = again. You must not start the lines with leading blanks or tabulators.

Examples of Valid Lines

x00-x1f = x00 All characters between x00 and x1f are converted to x00.
x00-x7f = x00-x7f All characters between x00 and x7f are not converted.
x00-x08 = x00,x01-x07,x00 The characters x00 and x08 are converted to x00 and characters between x01 and x07 are not converted.

ISALPHA = x41-x5a,x61-x7a,xc0-xd6,xd8
ISALPHA = xd9-xf6,xf8-xff

The attribute ISALPHA is assigned to all characters specified in these two lines.

Examples of Invalid Lines

x41 = 'A' All characters must be specified in hexadecimal format.
0x00-0x1f = 0x00 Hexadecimal values have to be specified in either of the following ways:


x00-x0f = x00,x01 The number of specified values does not correspond to the number of elements in the key range.