Display Files: Difference between revisions
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===Structure=== | ===Structure=== | ||
Display files are standard ASCII text files. They can be modified with text editors and some word processors. Display files can be printer files, or streams of characters to be sent to a printer. Display files have variable-length records with an optional programmer-specified record delimiter (see [[OPEN display]]'s EOL parameter for more information about this feature). The default record length for a display file is 132 characters (this is also true for most wide-carriage printers). | Display files are standard [[ASCII]] text files. They can be modified with [[text editors]] and some [[word processors]]. Display files can be [[printer files]], or streams of characters to be sent to a printer. Display files have variable-length records with an optional programmer-specified record delimiter (see [[OPEN display]]'s [[EOL]] parameter for more information about this feature). The default record length for a display file is 132 characters (this is also true for most wide-carriage printers). | ||
The record length in a display file has no impact on input processing. It is possible to input strings which are longer than the record length (provided the input variables are dimensioned large enough). On output, a string that is longer than the record length will be broken into records of 132 characters (or the specified record length). | The record length in a display file has no impact on input processing. It is possible to input strings which are longer than the record length (provided the input variables are dimensioned large enough). On output, a string that is longer than the record length will be broken into records of 132 characters (or the specified record length). | ||
===Viewing the contents=== | ===Viewing the contents=== | ||
The contents of a display file can be examined or displayed with Business Rules TYPE command. | The contents of a display file can be examined or displayed with Business Rules [[TYPE]] [[command]]. | ||
===Use with SORT and INDEX=== | ===Use with SORT and INDEX=== | ||
Display files cannot be used as indexed files and cannot be sorted by Business Rules built-in file sort. They can be sorted on by the AIDX and DIDX functions as used in the MAT statement (see MAT M in the statements | Display files cannot be used as indexed files and cannot be sorted by Business Rules! built-in file sort. They can be sorted on by the [[AIDX]] and [[DIDX]] functions as used in the [[MAT statement]] (see MAT M in the statements and AIDX or DIDX for more information). | ||
===File I/O=== | ===File I/O=== | ||
Display files may be opened for either INPUT or OUTPUT. As OUTIN is not supported (except with communications files), display files can be difficult to update. Only the sequential access method is allowed on display files. The statements that can be used for input from display files are INPUT and LINPUT. Formatted input is not allowed. Output (either formatted or unformatted) to display files is accomplished with the PRINT statement. | Display files may be opened for either [[INPUT]] or [[OUTPUT]]. As [[OUTIN]] is not supported (except with [[communications files]]), display files can be difficult to update. Only the [[sequential access]] method is allowed on display files. The statements that can be used for input from display files are [[INPUT]] and [[LINPUT]]. Formatted input is not allowed. Output (either formatted or unformatted) to display files is accomplished with the [[PRINT statement]]. | ||
<noinclude> | <noinclude> | ||
[[Category:File Operations]] | [[Category:File Operations]] | ||
</noinclude> | </noinclude> | ||
Latest revision as of 16:08, 6 January 2014
Business Rules! uses display files to store procedures, source programs and the BRConfig.sys file. See also Open Display
Structure
Display files are standard ASCII text files. They can be modified with text editors and some word processors. Display files can be printer files, or streams of characters to be sent to a printer. Display files have variable-length records with an optional programmer-specified record delimiter (see OPEN display's EOL parameter for more information about this feature). The default record length for a display file is 132 characters (this is also true for most wide-carriage printers).
The record length in a display file has no impact on input processing. It is possible to input strings which are longer than the record length (provided the input variables are dimensioned large enough). On output, a string that is longer than the record length will be broken into records of 132 characters (or the specified record length).
Viewing the contents
The contents of a display file can be examined or displayed with Business Rules TYPE command.
Use with SORT and INDEX
Display files cannot be used as indexed files and cannot be sorted by Business Rules! built-in file sort. They can be sorted on by the AIDX and DIDX functions as used in the MAT statement (see MAT M in the statements and AIDX or DIDX for more information).
File I/O
Display files may be opened for either INPUT or OUTPUT. As OUTIN is not supported (except with communications files), display files can be difficult to update. Only the sequential access method is allowed on display files. The statements that can be used for input from display files are INPUT and LINPUT. Formatted input is not allowed. Output (either formatted or unformatted) to display files is accomplished with the PRINT statement.