Guardian Procedure Calls Reference Manual

List-Directed Input
All input forms that are acceptable to FORMATDATA when directed by a format are acceptable
for list-directed input, with these exceptions:
• When the data element is a complex variable, the input form consists of a left parenthesis
followed by an ordered pair of numeric input fields separated by a comma and followed by
a right parenthesis.
• When the data element is a logical variable, the input form must not include either slashes or
commas among the optional characters for the L editing.
• When the data element is a character variable, the input form consists of a string of characters
enclosed in apostrophes. The blank, comma, and slash may appear in the string of characters.
• A null value is specified by having no characters other than blanks between successive value
separators, no characters preceding the first value separator in the first buffer, or the r* form.
A null value has no effect on the value of the corresponding data element. The input list item
retains its previous value. A single null value must represent an entire complex constant (not
just part of it).
If a slash value separator is encountered during the processing of a buffer, data conversion is
terminated. If there are additional elements in the data list, the effect is as if null values had been
supplied for them.
On input, a value separator is one of these:
• A comma or slash optionally preceded or optionally followed by one or more contiguous
blanks (except within a character constant).
• One or more contiguous blanks between two constants or following the last constant (except
embedded blanks surrounding the real or imaginary part of a complex constant).
• The end of the buffer (except within a character constant).
List-Directed Output
Output forms that are produced by list-directed output are the same as that required for input with
these exceptions:
• The end of a buffer can occur between the comma and the imaginary part of a complex
constant only if the entire constant is as long as, or longer than, an entire buffer. The only
embedded blanks permitted within a complex constant are between the comma and the end
of a buffer, and one blank at the beginning of the next buffer.
• Character values are displayed without apostrophes.
• If two or more successive character values in an output record produced have identical values,
the FORMATDATA procedure produces a repeated constant of the form r*c instead of the
sequence of identical values.
• Slashes, as value separators, and null values are not produced by list-directed output.
For output, the value separator is a single blank. A value separator is not produced between or
adjacent to character values.
1570 Formatter Edit Descriptors