GoFiler Legato Script Reference   Legato v 1.5d Application v 5.25a

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Chapter Three — Data Types and Operators

3.1 Variables and Symbols

3.1.1 Variables

A variable can be defined as a portion of memory that stores a value. The value of a variable is stored in an unspecified memory location. To refer to that value, simply refer to the variable by its identifier or name.

Variables names are a sequence of any number of digits, letters, and underscore (“_”) characters. The name cannot begin with a number. Special reserve characters, punctuation, and spaces are not permitted as part of a valid variable name. In addition, Legato keywords, such as if and else, cannot be used as variable names (for a complete list of Legato SDK definitions, see Appendix A — Legato SDK Standard Definitions). Legato variable names are case-sensitive.

Examples of valid variable names:

	a	x5	Q_A	CharlieBrown	hWindow	_cat
	$a	baño	@7	_	@

 

Examples of invalid names:

	16b	0x5	my-list	if	while	$6
	z,y	[p]	:n	a.a	k|l

 

[UTF-8/UTF-16 names are not supported at this time]

Operations (such as mathematical addition and subtraction) can be performed on variables with operators. One of the most fundamental operations is the assignment of a value to a variable, as shown below:

i = 5;

r = 16.33;

n = 0x12;

s = "cat";

c = 'x'

For a more in depth discussion of operators, see Section 3.11 Operators.

3.1.2 Declaration

In Legato, variables must be declared before they can be used. In its simplest form, a declaration is two parts: the variable type and the variable name. For example:

int i;

char a[];

The first statement declares a variable named i that is of the integer type. The second declares a variable named a that is an array of character values. Initialization refers to assigning a value to a variable for the first time. All variables are set to zero or empty automatically, unlike C or C++ where uninitialized variables can contain garbage. [Often initiation and declaration can occur in the same programmatic expression:]

int i = 5;     ‡

Variables can be declared and initialized anywhere within a script so long as they are declared and initialized before they are used. However, programmatic clarity is improved when variables are declared (and initialized as necessary) at the beginning of the script.

3.1.3 Introduction to Data Types

Every variable has a type associated with it. This type specifies the amount of memory that must be allocated to store the value. On a more practical level, it also determines what type of data can be stored in that memory location. The type of a variable is strict, which means that once it is declared, it cannot be changed.

There are many types of data. Incorporating these varying data types allows Legato to interface with external programs directly or easily read and write binary data. Also, when arrays of information are required, allowing the use of smaller types can significantly reduce memory requirements. 

The following table lists the fundamental data types available in Legato.

Keyword	Description	Uses/Comment
Integers:
byte	8-bit unsigned value	Typically used in buffers of data.
short	16-bit signed value	Small signed integer.
word	16-bit unsigned value	Used to convey unsigned data and for bitwise information.
int	32-bit signed value	The default signed integer value.
dword	32-bit unsigned value	Used frequently to present bitwise data.
long	64-bit signed value	Used for large numbers.
qword	64-bit unsigned value	Used for date/time and large numbers.
Floating-Point:
float	64-bit floating-point	Floating-point or real numbers. Note, there are certain considerations when using and comparing floating-point numbers.
real	32-bit	[currently 64 bits, to be adjusted]
double	64-bit	[does not exist]
Strings:
char	8-bit	A character representation of ANSI textual data.
string	8-bit array	Natural array or string of characters.
wchar	16-bit	Wide character for Unicode textual data.
wstring	16-bit array	Natural array or string of wide characters.
Other:
boolean	8-bit	A logical representation of TRUE and FALSE, 1 and 0 respectively.
handle	32-bit	A unique number that represents an abstract object, process, file, window, etc...
object	—	A collection data and functions. [not done]

Some types of data pertain to lower-level computing operations, such as the type byte and other types used in bitwise operations. Other types may contain memory addresses. The type of the variable tells the interpreter how to access and manage the information the variable represents. 

 

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GoFiler Legato Script Reference — Generated on 12/16/2024

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