This document describes how COBOL data items and related syntax are mapped to Software AG IDL by the IDL Extractor for COBOL using the Extractor Wizard and Mapping Editor.
This document covers the following topics:
The IDL Extractor for COBOL maps the following subset of COBOL data types to Software AG IDL data types.
The following metasymbols and informal terms are used for the IDL in the table below.
The metasymbols "[" and "]" surround optional lexical entities.
The informal terms n and
m are sequences of numeric characters, for example
123.
| COBOL Data Type | Software AG IDL Data Type | Notes | |||
|---|---|---|---|---|---|
| Alphabetic | PIC A(n) |
An, AVn |
Alphanumeric | 1,2 | |
| DBCS | PIC G(n) |
Kn*2, KVn*2 |
Kanji | 1,2,3 | |
| DBCS | PIC N(n) [USAGE] [IS] DISPLAY-1 |
Kn*2, KVn*2 |
Kanji | 1,2,3 | |
| Unicode or DBCS | PIC N(n) |
Un, UVn or Kn*2, KVn*2 |
Unicode or Kanji | 1,2,3,10 | |
| Unicode | PIC N(n) [USAGE] [IS] NATIONAL |
Un, UVn |
Unicode | 1,2 | |
| Alphanumeric | PIC X(n) |
An, AVn |
Alphanumeric | 1,2 | |
| Numeric | Zoned decimal | PIC 9(n)[V9(m)] |
NUn[,m] |
Unpacked decimal unsigned | 2,4,8 |
| Zoned decimal | PIC S9(n)[V9(m)] |
Nn[,m] |
Unpacked decimal | 2,4,8 | |
| Packed decimal | PIC 9(n) [V9(m)] COMP[UTATIONAL]-3 |
PUn[,m] |
Packed decimal unsigned | 2,4,8 | |
| Packed decimal | PIC S9(n) [V9(m)] COMP[UTATIONAL]-3 |
Pn[,m] |
Packed decimal | 2,4,8 | |
| Packed decimal | PIC 9(n) [V9(m)] PACKED-DECIMAL |
PUn[,m] |
Packed decimal unsigned | 2,4,8 | |
| Packed decimal | PIC S9(n) [V9(m)] PACKED-DECIMAL |
Pn[,m] |
Packed decimal | 2,4,8 | |
| Binary | PIC [S]9(n) BINARY (1=n=4) |
I2 |
Integer (medium) | 2,4,5,6,7 | |
| Binary | PIC [S]9(n) BINARY (5=n=9) |
I4 |
Integer (large) | 2,4,5,6,7 | |
| Binary | PIC [S]9(n) COMP[UTATIONAL][-4] (1=n=4) |
I2 |
Integer (medium) | 2,4,5,6,7 | |
| Binary | PIC [S]9(n) COMP[UTATIONAL][-4] (5=n=9) |
I4 |
Integer (large) | 2,4,5,6,7 | |
| Binary | PIC [S]9(n) COMP-5 (1=n=4) |
I2 |
Integer (medium) | 2,4,6,7 | |
| Binary | PIC [S]9(n) COMP-5 (5=n=9) |
I4 |
Integer (medium) | 2,4,6,7 | |
| Floating point | COMP[UTATIONAL]-1 |
F4 |
Floating point (small) | 9 | |
| Floating point | COMP[UTATIONAL]-2 |
F8 |
Floating point (large) | 9 | |
| Alphanumeric-edited | Alphanumeric item containing "0" or "/"
|
A(length of PIC) |
Alphanumeric | 11 | |
| Numeric-edited | Numeric item containing "DB", "CR", "Z", "$",
".", ",", "+", "-", "*", "B", "O" or "/"
|
A(length of PIC) |
Alphanumeric | 11 | |
Mapping to fixed-length or variable-length Software AG IDL data type is controlled in the extraction settings of the extraction wizard, see Step 4: Define the Extraction Settings and Start Extraction.
Equivalent alternative forms of the PICTURE clause, e.g. XXX,
AAA,NNN, GGG or 999 may also be used.
The length for IDL data type is given in bytes. For COBOL the length is in DBCS characters (2 bytes).
The character "P[(n)]" stands for a decimal scaling position, this
character has no effect on the length of the generated data type. Only the data
fraction will be mapped to the Software AG IDL:
01 GROUP1. 10 FIELD1 PIC PPP9999.
will be mapped to IDL:
1 GROUP1 2 FIELD1 NU4
Behavior depends on the COBOL compiler settings:
With COBOL 85 standard, the value range depends on the number of
digits in the PICTURE clause. This differs from the value range of the IDL data
type using the binary field size instead. If the parameter is of direction "in"
your RPC client application has to ensure the integer value sent is within the
allowed range. See Software AG IDL Grammar.
With no COBOL 85 standard, the value range of the COBOL data type reflects the binary field size, thus matches the IDL data type exactly. In this case, there are no restrictions regarding value ranges. For example:
with operating system z/OS and IBM compiler, see option
TRUNC(BIN) in your COBOL compiler documentation
with operating systems UNIX and Windows and a Micro Focus
compiler, see option NOTRUNC in your Micro Focus COBOL
documentation.
For unsigned COBOL data types (without "S" in the PICTURE clause) the
value range of the IDL data type differs:
IDL allows negative values, COBOL does not.
For I2, the maximum is 32767 for IDL instead of 65535 for COBOL.
For I4, the maximum is 2147483647 for IDL instead of 4294967294 for COBOL.
Binaries with more than 9 digits in the PICTURE clause
cannot be mapped to IDL. See the following table:
S9(10) thru S9(18) |
Binary doubleword (8 bytes) | -9,223,372,036,854,775 thru +9.223,372,036,854,775 |
9(10) thru 9(18) |
Binary doubleword (8 bytes) | 0 thru 18,446,744,073,709,551 |
The value range of PACKED-DECIMAL and ZONED-DECIMAL is greater than the
value range of the mapped IDL data type. COBOL supports 31 digits (IBM and
Fujitsu Siemens), 38 digits (Micro Focus), and IDL 29 digits. If the COBOL
program uses more than 29 digits for a PACKED-DECIMAL or ZONED-DECIMAL, it cannot
be mapped to IDL.
The precision (digits after decimal point) of
PACKED-DECIMAL and ZONED-DECIMAL is greater than the value range of the mapped IDL
data type, which is 7. If the COBOL program uses more than 7 digits after the
decimal point for a PACKED-DECIMAL or ZONED-DECIMAL, it cannot be mapped to IDL.
Only the IDL range 0=n=7 and 1=(m+n)=29 is supported.
COMPUTATIONAL-1 (4-byte, single precision) and COMPUTATIONAL-2 items
(8-byte, double precision) items are an IBM-specific extension. When
floating-point data types are used, rounding errors can occur, so the values of
senders and receivers might differ slightly.
If this form is extracted from a COBOL program originally written for
Micro Focus COBOL and operating system UNIX or Windows, the mapping to the IDL
data type depends on the setting in the IDL Extractor for COBOL Preferences.
See Meaning of PIC N without USAGE clause within pane
Compiler Directives of
Step 2: Define the Default Settings. For all other COBOL
program extractions, the mapping is always to IDL data type
Un/Uvn.
COBOL alphanumeric/numeric edited items will force the generation of
IDL data type A with an inline comment containing the original COBOL
PICTURE clause. The CURRENCY SIGN clause in the
SPECIAL-NAMES and the CURRENCY compiler option is not considered.
This section discusses the syntax relevant for extracting the
DATA DIVISION:
The BLANK WHEN ZERO clause specifies that an item
contains nothing but spaces when its value is zero. The BLANK WHEN
ZERO clause is not considered by the IDL Extractor for COBOL. The
DATA DIVISION is parsed as without the BLANK WHEN
ZERO clause. Because the BLANK WHEN ZERO clause only has an
impact if the item is displayed, such a program can be mapped to IDL. The
workaround for RPC clients is to imitate the BLANK WHEN ZERO
clause.
See the following syntax:
| Format | COBOL Syntax |
|---|---|
| 1 | 88 |
| 2 | 88 |
| 2 | 88 |
Semantically, level-88 condition names can be
Enumeration Type Values
If your COBOL server requires the level-88 value to be provided on a
call-by-call basis, i.e. the value may change with every call, map the level-88
base variable to a simple IDL parameter with the desired direction IN, OUT or
INOUT. RPC clients have to pass correct values, same as defined by the level-88
condition names.
Single Constant Values
If your COBOL server interface expects for your purpose always a
constant value, map the level-88 condition names to a constant. See Mapping COBOL Data Items to Constants.
Function or Operation Codes
If the level-88 values are function or operation codes, map the
level-88 condition names to an operation. This will lead to an IDL program per
operation code. See Mapping COBOL Functions to Multiple IDL Programs.
The through values of the level-88 condition names (see format 2 in the table above) are not considered by the IDL extractor for COBOL. The DATA DIVISION is parsed as without level-88 through values.
Continuation lines, starting with a hyphen in the indicator area, are supported.
The DATE FORMAT clause is an IBM-specific extension. The
DATE FORMAT clause specifies that a data item is a windowed or
expanded date field.
The DATE FORMAT clause is not considered by the
IDL Extractor for COBOL. The DATA DIVISION is parsed as without
the BLANK WHEN ZERO clause. The semantic given by the DATE
FORMAT clause has to be considered by RPC clients.
In the check box Map FILLER fields to IDL of the
COBOL to IDL in the extraction settings of the wizard (see Step 4: Define the Extraction Settings and Start Extraction) you can define whether COBOL
FILLER pseudo-parameters should be part of the RPC client interface by default
or not. By default they are not mapped to IDL. In the
COBOL Mapping Editor you can change the
mapping for a FILLER field individually, e.g. mapping required ones to IDL. If
FILLER fields are mapped to IDL, they are made unique by appending a sequence
number. If the resulting names are not suitable, you can rename IDL field names
in the mapping editor with the function of
the context menu. See the following example:
01 GROUP1. 10 FIELD1 PIC XX. 10 FILLER PIC XX. 10 FIELD2 PIC S99. 10 FILLER PIC XX.
This will be mapped to Software AG IDL:
1 GROUP1 2 FIELD1 (A2) 2 FILLER_1 (A2) 2 FIELD2 (N2.0) 2 FILLER_2 (A2)
If a group is named FILLER and the group has scalar fields, the group
is always mapped to IDL, independent of the check box Map FILLER
fields to IDL. For example:
01 GROUP1. 10 FIELD1 PIC XX. 10 PIC XX. 10 FIELD2 PIC S99. 10 FILLER PIC XX. 10 . 20 FIELD3 PIC S9(4) BINARY. 20 FIELD4 PIC S9(4) BINARY.
This will be mapped to Software AG IDL:
1 GROUP1 2 FIELD1 (A2) 2 FILLER_1 (A2) 2 FIELD2 (N2.0) 2 FILLER_2 (A2) 2 FILLER_3 3 FIELD3 (I2) 3 FIELD4 (I2)
The GLOBAL clause
specifies that a data-name is available to every program contained within the program that declares it, as long as the contained program does not itself have a declaration for that name.
is not considered by the IDL Extractor for COBOL. The DATA
DIVISION is parsed as without the GLOBAL clause.
However, program parameters containing the GLOBAL clause
can be mapped to IDL, which can make sense as long as the EXTERNAL
DATA clause is used to pass parameters from the called COBOL server to
further subprograms called.
The EXTERNAL clause
can only be specified on data description entries that are in the Working-Storage section of a program.
is not considered by the IDL Extractor for COBOL. The DATA
DIVISION is parsed as without the EXTERNAL clause.
Note:
EntireX RPC technology cannot pass data using
EXTERNAL linkage from the RPC server to the COBOL server. However,
program parameters containing the EXTERNAL clause can be mapped to
IDL, which can make sense as long as the EXTERNAL DATA clause is
used to pass parameters from the called COBOL server to further subprograms
called.
The IDL Extractor for COBOL ignores the JUSTIFIED clause.
The DATA DIVISION is parsed as without the JUSTIFIED
clause. The workaround for RPC clients is to imitate the JUSTIFIED
clause.
The OBJECT REFERENCE phrase is an IBM-specific extension.
A program containing an OBJECT REFERENCE phrase cannot be mapped
to IDL.
Numbers in the first position of the parameter name are not allowed in Software AG IDL syntax (see Software AG IDL Grammar). Thus COBOL names starting with a number are prefixed with the character "#" by default. You can rename all IDL parameters in the COBOL Mapping Editor. For example,
01 1BSP PIC XXX.
by default will be mapped to Software AG IDL:
01 #1BSP A(3).
If a parameter name is not specified, e.g.
01 GROUP1. 10 FIELD1 PIC XX. 10 PIC XX. 10 FIELD2 PIC S99. 10 FILLER PIC XX. 10 . 20 FIELD3 PIC S9(4) BINARY. 20 FIELD4 PIC S9(4) BINARY.
see FILLER Pseudo-Parameter above.
The POINTER phrase is an IBM-specific extension.
| COBOL Syntax | Software AG IDL Syntax |
|---|---|
1 |
none |
1 |
none |
All pointers are mapped to "suppressed" in the mapping editor because the Software AG IDL does not support pointers. Offsets to following parameters are maintained by the Server Mapping File (SVM). At runtime, the RPC server passes a null pointer to the COBOL server.
The PROCEDURE-POINTER phrase is an IBM-specific
extension. A program containing a procedure-reference phrase cannot be mapped
to IDL.
A redefinition is a second parameter layout of the same memory portion. In most modern programming languages, and also the Software AG IDL, this is not supported. With the wizard you can select a single redefine path for IDL usage. You can do this in the
Select the single REDEFINE path for a level 1
REDEFINE unit (all redefine paths addressing the same storage
location) in the parameter selection window. See Step 5: Select the COBOL Parameters in Using the
IDL Extractor for COBOL. This is the simplest and most
straightforward approach for a COBOL server with a single interface, because
All REDEFINE siblings are no longer considered. Further processing
is like a single parameter for the level 1 REDEFINE path.
Select the complete REDEFINE unit on level 1 with all
paths for a COBOL server with multiple interfaces that have to be mapped to
operation (see Mapping COBOL Functions to Multiple IDL Programs), and where each
operation interface is described by a level 1 REDEFINE path in the
parameter selection window. See Step 5: Select the COBOL Parameters in
Using the IDL Extractor for COBOL. Then model the operation
interfaces in the mapping editor to IDL programs.
Only REDEFINE units on level 1 can be selected in the
parameter selection. REDEFINE units on level greater than 1 have
to be selected in the mapping editor, see below.
For all REDEFINE units on level greater than 1, the
REDEFINE path used by your interface has to be selected in the
mapping editor. See Selecting REDEFINE Paths in the mapping editor.
For REDEFINE units on level 1 that are not selected
uniquely in the parameter selection window above, map the required
REDEFINE path to IDL. See Selecting REDEFINE Paths in the mapping editor.
See also Step 6: Map the COBOL Interface to IDL with the Mapping Editor in Using the IDL Extractor for COBOL.
If a REDEFINE path is selected, the mapping is as
follows:
| COBOL Syntax | Software AG IDL Syntax |
|---|---|
1 [ |
1 |
1 FILLER REDEFINES |
1 FILLER_ |
Level-66 entries are ignored and cannot be used for mapping to IDL.
The DATA DIVISION is parsed as without the level-66 entry.
The SIGN LEADING and TRAILING SEPARATE
clause is supported. The mapping is internal within the
Server Mapping File (SVM).
The synchronized clause aligns COBOL data items at word boundaries. The clause does not have any relevance for RPC clients and is not written into the IDL file but into the Server Mapping File. At runtime, the RPC server aligns the data items accordingly.
Fixed sized COBOL tables are converted to fixed size IDL arrays. See the following syntax.
| COBOL Syntax | Software AG IDL Syntax |
|---|---|
1 |
1 |
1 |
1 |
1 |
1 |
The combination of the ASCENDING and INDEXED
BY phrase as well as DESCENDING and INDEXED BY
phrase is also supported.
Variable size COBOL tables are converted to unbounded groups with a maximum upper bound set. The lower-bound is always set to 1. The index is not part of the IDL, but it is in the SVM file. See the following example:
01 COUNTER-1 PIC 99. 01 TABLE OCCURS FROM 1 TO 10 DEPENDING ON COUNTER-1 02 FIELD1 PIC XX. 02 FIELD2 PIC 99.
A variable length group (with maximum) will be defined. A presence of the index in the IDL would be wrong, because the number of elements is implicitly available with the unbounded group. Therefore the index is not part of the IDL, but the mapping is within the Server Mapping File (SVM).
01 TABLES (/V10) 02 FIELD1 (A2) 02 FIELD2 (NU2.0)
| COBOL Syntax | Software AG IDL Syntax |
|---|---|
1 |
1 |
1 |
1 |
1 |
1 |
The data item referenced by the OCCURS DEPENDING ON
clause has to be part of the COBOL server interface as well - in the same COBOL
parameter direction. This means that if the variable-size table is selected in
the COBOL Parameter Selection page of the wizard as a
COBOL INOUT Parameter (see Step 5: Select the COBOL Parameters), the index data item (ODO
subject) must be selected as a COBOL INOUT parameter as
well.
COBOL IN Parameter, the index data
item (ODO subject) must be selected as a COBOL IN
parameter as well.
COBOL OUT Parameter, the index data
item (ODO subject) must be selected as a COBOL OUT
parameter as well.
If the index data item (ODO subject) is not selected
correctly with the variable-size table, unexpected behavior occurs.
The COBOL from value, n above, is semantically different
from the IDL lower bound and means a lower-bound of elements which must not be
crossed. It is the duty of the calling RPC client to take care of this and set
the corresponding number of elements correctly. Do not send less than the COBOL
lower bound.
The combination of the ASCENDING and INDEXED
BY phrase as well as DESCENDING and INDEXED BY
phrase is also supported.
COBOL level-77 data items are handled as COBOL data items on level 1. They are always mapped to IDL level 1.
A USAGE clause can be specified on group level, which
defines the data type of subsequent groups or parameters. The
USAGE clause on subsequent groups or parameters may not contradict
a higher level definition. Therefore IDL data types may depend on
USAGE clauses of parent groups if the COBOL data structure is
defined as explained.
COBOL data items defined with USAGE IS INDEX are parsed
as without USAGE IS INDEX. The USAGE IS INDEX clause
is ignored.
The VALUE clause specifies the initial contents of a data item or the
value(s) associated with a condition name. For condition names, see Condition Names - Level-88 Data Items above.
| COBOL Syntax |
|---|
1 |
Initial values can be specified on data items in the Working-Storage Section. As an IBM extension, in the File and Linkage Sections, the VALUE clause is treated as a comment.
The IDL Extractor for COBOL ignores initial values of data items. The
DATA DIVISION is parsed as without the VALUE clause.
This section discusses the syntax relevant for extraction of the
PROCEDURE DIVISION:
For batch and IMS programs the PROCEDURE DIVISION header
is relevant for the COBOL INOUT parameters. The parameters of the header are
suggested as default COBOL INOUT parameters in the
COBOL Parameter Selection.
For CICS, the PROCEDURE DIVISION header is of no
interest, because the DFHCOMMAREA is the relevant information to get the COBOL
INOUT parameters from. If the DFHCOMMAREA is defined in the linkage section all
parameters of the DFHCOMMAREA are suggested as default COBOL INOUT parameters
in the COBOL Parameter Selection. If there is no DFHCOMMAREA there is no suggestion.
However, you can always add, change and correct the suggested parameters if they are not the correct ones in the extraction wizard. See also Step 5: Select the COBOL Parameters in Using the IDL Extractor for COBOL.
The BY VALUE clause is an IBM-specific extension for
COBOL batch programs. It is ignored by the IDL Extractor for COBOL. Directions
are added in the mapping editor manually; see Providing IDL Directions (IN OUT INOUT). See also
Step 6: Map the COBOL Interface to IDL with the Mapping Editor in Using the
IDL Extractor for COBOL.
The RETURNING phrase is an IBM-specific extension for
COBOL batch programs. It is ignored by the IDL Extractor for COBOL. Handling is
as without the phrase. No return value is transferred during execution time. If
the RETURNING phrase is relevant for the interface, the COBOL
program cannot be mapped to IDL.
COPY statements are supported if nested copy statements do not recursively call the same source file.
If copybooks cannot be located, the following rules apply:
In the case of a remote extraction, the copybook location (data set) is unknown.
In the case of a local extraction, either the copybook location (directory) or the copybook extension is unknown.
In both cases, the extraction wizard will appear with a dialog to browse for the copybook location (local directory or remote data set) and allows you to append your copybook extensions. Both will be saved in the preferences.
You can also predefine the following in the preferences:
the copybook locations, see Step 4: Define the Remote Copybook Locations or Step 4: Define the Local Copybook Locations in IDL Extractor for COBOL Preferences.
the copybook extensions for local extractions, see Step 4: Define the Local Copybook Locations in IDL Extractor for COBOL Preferences.
COPY statements with the REPLACE option are supported. Beneath the
REPLACE option, those copybooks are worked off like all other copybooks above.
Example:
a copybook ACPYBK with REPLACE option
01 WS-ZEUGNIS.
:F: WS-AKTIONEN PIC 9(01).
:L: :C:-NEU VALUE 'N'.
:L: :C:-MOD VALUE 'M'.
:L: :C:-INS VALUE 'I'.
:L: :C:-WEG VALUE 'W'.
:L: :C:-SIG VALUE 'S'.
:F: WS-NOTEN PIC X(03).
:L: SEHR-GUT VALUE 100.
:L: GUT VALUE 95 THROUGH 99.
:L: BEFRIEDIGEND VALUE 80 THROUGH 94.
:L: AUSREICHEND VALUE 50 THROUGH 79.
:L: MANGELHAFT VALUE 01 THROUGH 49.
:L: UNGENUEGEND VALUE 0.
referencing the copybook above
COPY ACPYBK
REPLACING
==:F:== BY ==10==,
==:L:== BY ==88==,
==:C:== BY ==CMD==,
95 BY 90,
94 BY 89,
WS-NOTEN BY WS-PROZENT,
==X(03)== BY ==9(03)==,
==9(01)== BY ==X(01)==.