Syntax: A single line

A raw line.

Syntax: A single line with leading spaces

Another raw line, with leading spaces.

Syntax: Area (block)

A raw area delimitted by lines with marks.

Syntax: Area (block) with trailing spaces

Trailing spaces and TABs after the area marks are allowed, but not encouraged nor documented.

Invalid: No space between mark and contents

"""Not a raw line, need one space after mark.

Invalid: Leading spaces on block marks

""" Not a raw area. The marks must be at the line beginning, no leading spaces. """

Closing: EOF closes the open block

The end of the file (EOF) closes the currently open raw area.