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Section 8.3.2.5:
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types SAME = CONTROL_CODES ; CONTROL_CODES = token ;
This class implements ISO 6429 control code names and properties.
The names of the codes are specified in the following table - all routines return a control code.
NUL | START_OF_HEADING | START_OF_TEXT |
END_OF_TEXT | END_OF_TRANSMISSION | ENQUIRY |
ACKNOWLEDGE | ALERT | BACKSPACE |
HORIZONTAL_TAB | LINE_FEED | VERTICAL_TAB |
FORM_FEED | CARRIAGE_RETURN | SHIFT_OUT |
SHIFT_IN | DATA_LINK_ESCAPE | DC1 |
DC2 | DC3 | DC4 |
NEGATIVE_ACKNOWLEDGE | SYNCHRONOUS_IDLE | END_OF_TRANSMISSION_BLOCK |
CANCEL | END_OF_MEDIUM | SUBSTITUTE |
ESCAPE | FILE_SEPARATOR | GROUP_SEPARATOR |
RECORD_SEPARATOR | UNIT_SEPARATOR | DELETE |
PADDING_CHARACTER | HIGH_OCTET_PRESET | BREAK_PERMITTED_HERE |
NO_BREAK_HERE | INDEX | NEXT_LINE |
START_OF_SELECTED_AREA | END_OF_SELECTED_AREA | CHARACTER_TABULATION_SET |
CHARACTER_TABULATION_WITH_JUSTIFICATION | LINE_TABULATION_SET | |
PARTIAL_LINE_FORWARD | PARTIAL_LINE_BACKWARD | REVERSE_LINE_FEED |
SINGLE_SHIFT_TWO | SINGLE_SHIFT_THREE | DEVICE_CONTROL_STRING |
PRIVATE_USE_ONE | PRIVATE_USE_TWO | SET_TRANSMIT_STATE |
CANCEL_CHARACTER | MESSAGE_WAITING | START_OF_GUARDED_AREA |
END_OF_GUARDED_AREA | START_OF_STRING | SINGLE_GRAPHIC_CHAR_INTRODUCER |
SINGLE_CHARACTER_INTRODUCER | CONTROL_SEQUENCE_INTRODUCER | STRING_TERMINATOR |
OPERATING_SYSTEM_COMMAND | PRIVACY_MESSAGE | APPLICATION_PROGRAM_COMMAND |
This predicate returns true if and only if the given numeric argument is a valid bit-pattern for representation of a control code.
is_valid(val : CARD) res : SAME
Since this operation is a predicate then this pre-condition is vacuously true.
Note that this post-condition performs an abstract character code creation in order to determine if the result is in the domain of the character repertoire. Such an operation could not be performed in general with executable code. It is used solely for specification purposes.
post let val_set : set of SAME = (NUL, ..., APPLICATION_PROGRAM_COMMAND) in create(val) in set val_set
This predicate returns true if and only if the bit-pattern of the numeric argument is a valid control code representation.
This feature creates a control code from the given numeric value, used as a bit-pattern.
create(val : CARD) res : SAME
pre is_valid(val)
post let loc_res : seq of OCTET be st loc_res = res in loc_res = [OCTET.create(val)]
This feature creates a new control code which has the bit-pattern representation which is the same as the value given.
This predicate returns true only if self is an encoding for a control function which occupies space on a presentation medium.
is_space(self : SAME) res : BOOL
Since this feature is a predicate and the argument is not optional then this pre-condition is vacuously true.
post let loc_sp : set of SAME = (BACKSPACE, ..., CARRIAGE_RETURN) in self in set loc_sp
This predicate returns true if and only if self is an encoding for a control function which produces unmarked space on a presentation medium.
This feature returns the numeric value of the bit-pattern of self as a cardinal number.
card(self : SAME) res : CARD
Since the argument is not optional then this pre-condition is vacuously true.
post create(res) = self
This feature returns the cardinal number corresponding to the code value (as a bit-pattern) of self.
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or enquiries should be made toKeith Hopper. Page last modified: Tuesday, 24 April 2001. |
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