STL

File types: .TXT .txt

Mixed capitalisations, such as .Txt, are also supported.

CAT can read and write catalogues in the STL (Small Text List) format. Unlike the other formats which CAT can access the STL format is specific to the CAT library. Nonetheless the STL format exists in order to allow easy access to both private tables and versions of standard catalogues held as text files. It is usually straightforward to create an STL catalogue from a text file containing a private list or standard catalogue.

In the STL format both the table of values for the catalogue and the definitions of its columns, parameters etc. are held in simple ASCII text files. These files may be created and modified with a text editor. The information defining the catalogue is called the description of the catalogue and the file in which it is held is called the description file.

When you specify a small text list you give the name of the description file. The table of values comprising the catalogue may either be in the same file as the description or in a separate file. If the table of values occurs in a separate file then the name of this file is specified in the description file and CAT places no restrictions on this name other than those imposed by the host operating system.

The STL format is fully documented in appendices to SUN/190[3], the manual for the catalogue and table manipulation package CURSA¹⁸. The documentation consists of a simple tutorial which is a good starting point and a complete description. In addition to the basic STL format there is a variant which allows STL format files to inter-operate with applications in the KAPPA image processing package (see SUN/95[3]). The KAPPA variant is also documented in SUN/190.

The CURSA documentation refers to various example files kept in directory:

/star/share/cursa

As a precaution against the unlikely eventuality that CAT is installed on your system but CURSA is not, there are copies of these files in directory:

/star/share/cat

The correspondence between items in an STL description and components in a CAT catalogue is obvious. In particular, STL data types convert to CAT ones in the obvious way.

CAT can read STL format catalogues with either a free format or a fixed-format table of values. However, CAT can only write STL format catalogues with a free format table. The KAPPA variant of the STL may be both read and written.

As its name implies, the Small Text List format is intended for use with relatively small catalogues and it is unsuitable for very large catalogues. Currently there is no upper limit to the size of catalogue for which it can be used. However, if you attempt to read a catalogue containing more than 15,000 rows a warning message is issued. A large STL format catalogue may take a while to open for reading and CAT may be unable to access a very large STL catalogue¹⁹.