Gala Language Guide

Gala is designed to be familiar if you come from a C-style language.

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Types

Each value in Gala has a type. Currently the supported types are the following:

Numeric

• int32
• int64
• float32
• float64
• bool

Strings

• string - unicode string

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Literals

Numeric

• int32 and int64 - Can be defined with binary, octal, decimal or hexadecimal literals.
  • Binary: 0b1010101
  • Octal: 0644
  • Decimal: 7618
  • Hexadecimal: 0x1fad
• float32 and float64 - Can be defined in decimal only. Scientific notation is allowed.
  • 12.34 or 123.456e7
• bool
  • Either true or false

Strings

String are surrounded by single (') or double (") quotes. Examples of string literals are

'I am a string - I can contain any character, such as 普'
"I am another string"

Strings are always unicode, therefore you can put any characters in them.

If you want to put a quote in a string, you can use a slash \ to escape them. Double the slash to escape the slash itself.

'I\'m fine with slashes!'
"This is what can be called a \"string\""
'This is a slash: \\'

Here are some special escapes for common carachters:

'This is a line\nAnd this another'
'\tThis line has a tab before'
'This is a carriage return: \r'
'This a backspace: \b'
'This a form feed: \f'

You can also input any unicode characters in decimal or hexadecimal as follows:

'This is the letter a: \97'
'This is again the letter a: \x61'
'Yet again the letter a: \u61'

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Variables

Variables are declared with the Go-like syntax variable_name type. For example:

year int32 = 2018;
load float32 = 0.57;
passed bool = true;

Expressions

Expressions are combinations of constants literals, variables operators and functions that has a value. An example of an expression is a sum like 3 + 4. Other example include:

7 * 8
(variable + 17) / 8
var1 or var2

Gala supports many standard operators, which are listed below.

Mathematical operators

• + and - - sum and difference
• * and / - product and quotient
• % - modulo or remainder
• - - negation as in -2 or -height
• ** - elevation to power as in 2**3 = 8

Logical operators

These

• and
• or
• not
• == - equality
• != - inequality
• < and <= - less and less than
• > and >= - greater and greater than

Object operators

• . - access property
• [] - indexing
• () - function call

Bitwise operators

• & - bitwise and
• ^ - bitwise xor
• | - bitwise or
• ~ - bitwise negation or bit flipping

Bitshifting is not (yet) supported

Ternary operator

Not supported

Operator precedence

Operators have precedence as follows (first has precedence on last):

Precedence	Operator
1	()
2	[]
3	.
4	-
5	~
6	not
7	**
8	%
9	*, /
10	+, -
11	<, <=, >, >=
12	==, !=
13	&
14	^
15	|
16	and
17	or

Statements

Gala supports common conditionals and loops statements.

Conditionals

The most common conditional is the if/else statement, which in Gala is exactly like in many other languages:

if (condition1) {
    ...
} else if (condition2) {
    ...
} else {
    ...
}

You can also remove the parenthesis:

if (condition) a = 1;

Functions

Functions are defined as follows

fun function_name(arg1 type1, arg2 type2) return_type {
    ...
}

Putting the type after the identifier is a bit different from other C-style languages, but is clear to read and remains readable even for function types. The type signature of the function will be:

fun (type1, type2) return_type

which can be read as “a function that takes type1 and type2 and returns return_type”.

Return statement

To return a value from a function, use the return statement:

fun generate_a_one() int32 {
    return 1;
}

Function invocation

To call a function and get the result, use the invocation syntax:

one inte32 = generate_a_one();

Main function

This feature may change in future releases, because it’s not very suitable for scripting.

Just like C, Gala uses a main function as entry-point for a program. A valid Gala program always has one and only one main function. Here an example of a valid Gala program:

fun main() int32 {
    // This is a complete program. Useless but complete.
}

Comments

Comments can have two different forms: line comments start with // and continue to the end of the line, while block comments start with /* and end with */ and can span multiple lines. Examples:

year int32 = 2018; // this part is ignored
load float32 = /* you should not put comments in such a place, but yeah it works */ 0.57;

/*
 * This is a boring function that always returns 1.
 * 
 * As such it's totally useless.
 */
fun generate_a_one() int32 {
    return 1;
}