'{
structure :=
error = ->[self error: ['"structure syntax error near: " , [self contents]]]
eol = '\r''\n'* | '\n''\r'*
space = [ \t]
comment = [-+] (!eol .)* eol
ws = (space | comment | eol)*
_ = space*
letter = [a-zA-Z]
digit = [0-9]
identifier = id:$(letter (letter | digit)*) _ -> [id asSymbol]
number = num:$digit+ _ -> [Integer fromString: num base: '10]
columns = '|' -> (structure-begin self)
( _ num:number -> [bitmap at: column put: (set bitpos num)]
(num:number)* '|' -> (let ()
(set bitpos num)
(set column [[self readPosition] - anchor]))
)+ eol ws -> [bitmap at: column put: (set width [bitpos + '1])]
row = ( n:number -> (set row n)
) ? '|' -> (let ()
(set anchor [self readPosition])
(set column '0))
_ ( id:identifier '|' -> (structure-field self id)
_ )+ eol ws -> (set row [row + width])
name = id:identifier (!eol .)* eol -> (structure-end id)
diagram = ws columns row+ name | error
}