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Semantics
The text of an AADL specification consists of a sequence
of separate lexical elements. Each
lexical element is formed from a sequence of characters, and is either a delimiter, an identifier, a
reserved word, a numeric_literal, a character_literal, a string_literal, or a comment. The meaning
of
an AADL specification depends only on the particular sequences of lexical elements that form its
compilations, excluding comments.
The text of an AADL specification is divided into lines.
In general, the representation for an end of
line is implementation defined. However, a sequence of one or more format_effectors other than
character tabulation (HT) signifies at least one end of line.
In some cases an explicit separator is required
to separate adjacent lexical elements. A separator
is any of a space character, a format_effector, or the end of a line, as follows:
A space character is a separator except within a comment,
a string_literal, or a character_literal.
Character tabulation (HT) is a separator except within
a comment.
The end of a line is always a separator.
One or more separators are allowed between any two adjacent
lexical elements, before the first, or
after the last. At least one separator is required between an identifier, a reserved word, or
a
numeric_literal and an adjacent identifier, reserved word, or numeric_literal.
A delimiter is either one of the following special
characters
(
) [ ] { } ,
. : ; =
* + -
or one of the following compound delimiters each
composed of two or three adjacent special
characters
::
=> +=> ->
->> .. -[ ]-> {** **}
Each of the special characters listed for single character
delimiters is a single delimiter except if
that character is used as a character of a compound delimiter, or as a character of a comment,
string_literal, character_literal, or numeric_literal.
The following names are used when referring to compound
delimiters:
Processing Requirements and Permissions
An implementation shall support lines of at least 200
characters in length, not counting any
characters used to signify the end of a line. An implementation shall support lexical elements
of at
least 200 characters in length. The maximum supported line length and lexical element length are
implementation defined. |
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