Syntax

Syntax & Basic Types

Comments

// various types of comments
x = 10; # Inline comment
/* This is a
   block comment */
    

Data Types

• Numbers: Integers (10) and Floating-point (3.14).
• Strings: Double-quoted ("Hello"), single-quoted ('Hello') text or multiline.
• Booleans: true and false.
• Arrays: Ordered lists ([1, 2, 3]).
• Maps: Key-value pairs (map { "key" : value }).
• Structs: User-defined complex objects.
• Date: Built-in simple date structure.
• Null: Represents missing value.

Variables & Constants

Variables are statically typed in Fahrenheit. You must specify a type (or multiple types) upon definition. Fahrenheit checks types at runtime and throws a ScriptException if an incompatible value is assigned. If you omit the type and assign a value on the first encounter, the type defaults to any.

# Mandatory typed variables
int count = 0;
String name = "Fahrenheit";
boolean isValid = true;

# Union types (allow multiple acceptable types)
String|int id = 5;
id = "five"; # Valid

# 'any' type (accepts any value)
any data = 10;
data = "hello"; # Valid

# Defaulting to 'any' by assigning on first use
x = 10; # x is of type 'any'

# Constants (immutable, must be typed)
constant double PI = 3.14159;
constant String VERSION = "0.4.0";
# PI = 3.14; # Error: Cannot assign to constant
    

Scope & Visibility

Fahrenheit uses block scoping. Variables declared within { } are local to that block. Modifiers control where variables are stored and their visibility:

• global: Stored in the global scope, accessible across script engines sharing context.
• local (default): Local to the current script execution.
• private, protected: For structure fields and methods (access control).

global String APP_NAME = "Fahrenheit App"; # Accessible everywhere
local int temp = 100;                      # Local to this script runner

structure Secure {
    private String key = "123";
    protected String secret = "abc";
    function String getKey() { return this.key; }
}
    

Operators

Standard arithmetic (+, -, *, /, %), comparison (==, !=, >, <, >=, <=), and logical (&&, ||, !) operators are supported.

Compound Assignment: +=, -=, *=, /= (works on numbers, strings, array elements, and struct fields)

Ternary Operator: condition ? val1 : val2 (right-associative, nestable)

Bitwise Operators: &, |, ^, ~, <<, >>, >>>

Operator Precedence (highest to lowest)

1. ( ) [ ] .
2. ! ~ - (unary)
3. * / %
4. + -
5. > >= < <= == !=
6. &&
7. ||
8. ? : (Ternary)
9. =

Strings

Single and Double Quotes: Strings can be delimited with either double quotes ("...") or single quotes ('......'). Mixed nesting is supported (a single-quoted string can contain double quotes and vice versa).

Interpolation: Embed expressions using """ + "$" + """expression syntax inside any string.

Multiline: Use triple-double-quotes ("""...""") or triple-single-quotes ('''...'''). Preserves whitespace and newlines. Supports interpolation.

name = "World";
print("Hello ${name}!");    // Output: Hello World!
print('Hi ${name}!');       // Output: Hi World!

# Multiline string
html = """
<div>
  <h1>Hello """ + "$" + """{name}</h1>
</div>
""";
    

Enumerations

Use the enumerated keyword for fixed sets of constants.

enumerated Status { PENDING, ACTIVE, INACTIVE }

global enumerated AppState { INIT, RUNNING, STOPPED }

status = Status.ACTIVE;
if (status == Status.ACTIVE) {
    print("User is active");
}
    

Control Flow

If-Else

if (x > 5) {
    print("High");
} else {
    print("Low");
}
    

Loops

# While
i = 0;
while (i < 5) { i = i + 1; }

# For
for (i = 0; i < 10; i = i + 1) { print(i); }

# Foreach (over arrays, strings, or maps)
foreach (item : list) { print(item); }
foreach (key : myMap) { print(key + " -> " + myMap[key]); }
    

Break and Continue

Use break to exit a loop early, and continue to skip to the next iteration. Both work inside while, for, and foreach loops.

for (i = 0; i < 10; i = i + 1) {
    if (i % 2 == 0) { continue; } # Skip even numbers
    if (i > 7) { break; }         # Stop early
    print(i);
}
    

Switch

switch (val) {
    case 1: print("One"); break;
    default: print("Other");
}
    

Exception Handling

try {
    throw "Error";
} catch (e) {
    print("Caught: " + e);
} finally {
    print("Cleanup");
}