Constants

Constants

2, 2.1828, 3.5cm, "string", T(two, two, deux)

Stack

Stack	Position	Description
Stack(In)	Top	-
Stack(Out)	Top	Value of the constant

InstantView® knows the following constants:

Type	Example	Value on the stack
Integer	3	integer
Numeric	3.14	transient object CX_NUMERIC
Value	3.14m	transient object CX_VALUE
String	"abc\ndef"	the character string
multiple string	T("three", three, trois)	multilingual character string (Note: The quote characters (") can be omitted if the partial text syntactically corresponds to an identifier)
Flag	NF_SET_PRECISION	Flag
INVALID	INVALID	Result when reading a slot that does not exist; All variables stop before the first value assignment INVALID
ACCESS_DENIED	ACCESS_DENIED	the result when reading access to data for which no Access rights exist

Negative numerical constants - Integer, Numeric, Value - must be enclosed in round brackets (to clearly distinguish the minus sign from the operator - ). The minus sign can be placed before or after the number. For some integer constants there are predefined identifiers.

A dimensioned constant (an object of the class CX_VALUE) is created when a whole or real number is followed by the name of a unit of measurement (in English). If the name of the unit of measurement (e.g. m for metre) was also used as a variable name or name of a statement, this has priority ( see example).

Special characters within a string are expressed in the same way as in C/C++:

	hexadecimal	Meaning
\n	0x0d	CR
\r	0x0a	LF
\f	0x0c	FF
\t	0x09	Tab
\b	0x08	BS
\\	0x5c	the sign \
\"	0x22	the sign "
\NN	Code of a byte as an octal number

\xNN	Code of a byte as hexadecimal number	Ex: "\x41" -> "A"
\U+NNNNNN	Unicode code of a letter as hexadecimal number	Ex: "\U+20AC" -> "€"

When specifying characters via octal or hexadecimal values, a maximum of as many characters are interpreted as a number as N occurs in the above table. You can specify fewer characters if they are not followed by a character that could also be interpreted as part of this number. In this case, the number must be filled with leading zeros.

Ex: "\U+20ACB" is interpreted as 1 Unicode character, but "\U+0020ACB" as "€B".

If strings of the form "class access::expression" are required as parameters (see instruction SetFormat), the string constant can also be written in the form Path(class::access-expression), whereby here - in contrast to the string notation "class::access-expression" - only syntactically correct constructions are possible. This notation is necessary if strings occur as function parameters in the access expression which themselves contain substrings in \"....\" (see example).

Note: The number of digits after the decimal point determines the precision of the CX_NUMERIC object

further examples ...