This section explains the requirements for specifying alternative pattern codes. These specifications are created as a table in a file which GT.M loads at run time.
Use the following keywords to construct your text file. Each keyword must:
Appear as the first non-whitespace entry on a line.
Be upper case.
The table names also must be uppercase. The patcodes are not case-sensitive.
PATSTART indicates the beginning of the definition text and must appear before the first table definition.
PATTABLE indicates the beginning of the table definition. The keyword PATTABLE is followed by whitespace, then the table name. The text file can contain multiple PATTABLEs.
PATCODE indicates the beginning of a patcode definition. The keyword PATCODE is followed by whitespace, then the patcode identifying character. On the next line enter a comma-delimited list of integer codes that satisfy the patcode. A PATCODE definition is always included in the most recently named PATTABLE. A PATTABLE can contain multiple PATCODEs.
PATEND indicates the end of the definition text; it must appear after the last table definition.
To continue the comma-delimited list on multiple lines, place a dash (-) at the end of each line that is not the last one in the sequence. To enter comments in the file, begin the line with a semi-colon (;).
The following example illustrates a possible patcode table called "NEWLANGUAGE," The example has definitions for patcodes "S," which would be a non-standard pattern character, and "L," which would substitute alternative definitions for the standard "L" (or lower case) pattern characters.
Example:
PATSTART PATTABLE NEWLANGUAGE PATCODE S 144,145,146,147,148,149,150 PATCODE L 230,231,232,233,234,235,236,237,238,239,240,241-,242,243,244,245,246,247,248,249,250,251,252,253,254,255 PATEND
Be mindful of the following items as you define your patcode table.
A table name can only be loaded once during an invocation of GT.M. It cannot be edited and reloaded, while the M process is running.
The table name "M" is a reserved designation for standard M, which is included in the GT.M run-time library.
Standard patcodes A and E cannot be explicitly redefined.
A is always the union of codes U and L; E always designates the set of all characters.
The C pattern code you define is used by GT.M to determine those characters which are to be treated as unprintable.
All characters not defined as C are treated as printable.