The default value for an StcsChan is zero, which causes the entire
STC-S description is written out by a single invocation of the sink
function. The text supplied to the sink function will not contain
any linefeed characters, and each pair of adjacent words will be
separated by a single space. The text may thus be arbitrarily large
and the StcsLength attribute is ignored.
If Indent is non-zero, then the text is written out via multiple
calls to the sink function, each call corresponding to a single
"line" of text (although no line feed characters will be inserted
by AST). The complete STC-S description is broken into lines so that:
- the line length specified by attribute StcsLength is not exceeded
- each sub-phrase (time, space, etc.) starts on a new line
- each argument in a compound spatial region starts on a new line
If this causes a sub-phrase to extend to two or more lines, then the
second and subsequent lines will be indented by three spaces compared
to the first line. In addition, lines within a compound spatial region
will have extra indentation to highlight the nesting produced by the
parentheses. Each new level of nesting will be indented by a further
three spaces.
Note, the default value of zero is unlikely to be appropriate when
an StcsChan is used within Fortran code. In this case, Indent
should usually be set non-zero, and the StcsLength attribute set to
the size of the CHARACTER variable used to
receive the text returned by AST_GETLINE within the sink function.
This avoids the possibility of long lines being truncated invisibly
within AST_GETLINE.