The beginning line of a fold must have the following syntax: the first
three characters are arbitrary and are followed by a `number sign' (#)
as the 4-th character and an opening square bracket ([) as the
fifth. After this comes the label, which may consist of any characters
with the exception of carriage returns, linefeeds and colons. A colon
(:) is used to terminate the label field and must be present! After the
colon, arbitrary characters are allowed as in normal text. The ending
line should look exactly the same as the beginning line in the range
between the number sign (#) and the colon (:) that terminates the
name field except that the fifth character ([) should be replaced
by a closing square bracket(]). The characters outside this field
(the first three or those following the colon) need not be the same.
When a fold has been closed the line that represents it is a copy of the
opening fold line (or beginning fold line) but it has a second `number
sign' where the opening fold line has its square bracket. The closed fold line may not be changed under any condition. If
you don't like it you have to open the fold first and change at least
the opening fold line.
With this syntax, the first three characters can be used to set off the line as commentary for a compiler, and the characters after the colon can be used as commentary for the programmer. Note also that tabs count as single characters so that when used in the first three characters of the line, a measure of indentation can be achieved.
Folds may be nested to any depth. The only restriction lies in a potential stack overflow, because some operations for nested folds work via a recursion. Typically at least 50 levels should be possible. Beyond that the reaction of stedi may depend on the computer on which it runs. If the stack is not protected agains overflow a crash may result. In practice the user will rarely go beyond 4 or 5 levels.