Syntax: A single line

A tagged line.

Syntax: A single line with leading spaces

Another tagged line, with leading spaces.

Syntax: Area (block)

A tagged area delimited 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 tagged line, need one space after mark.

Invalid: Leading spaces on block marks

''' Not a tagged 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 tagged area.