The characters space, tab, newline, and return are called
whitespace characters. Whitespace is used as necessary to separate
lexical symbols, such as integers, identifiers, or keywords. For example
Thorondor is a single identifier, while
Th or ondor is the keyword
or between the two identifiers
ondor. Whitespace may occur
between any two symbols, but not within a symbol. Two or more adjacent
whitespaces are equivalent to a single whitespace. Apart from the role
as separator of symbols, whitespaces are otherwise insignificant.
Whitespaces may also occur inside a string, where they are significant.
Whitespaces should also be used freely for improved readability.
A comment starts with the character
#, which is sometimes called
sharp or hatch, and continues to the end of the line on which the comment
character appears. The whole comment, including
# and the newline
character is treated as a single whitespace. Inside a string, the
# looses its role and is just an ordinary character.
For example, the following statement
if i<0 then a:=-i;else a:=i;fi;
is equivalent to
if i < 0 then # if i is negative a := -i; # take its inverse else # otherwise a := i; # take itself fi;
(which by the way shows that it is possible to write superfluous comments). However the first statement is not equivalent to
since the keyword
if must be separated from the identifier
i by a
whitespace, and similarly
a must be
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