Types and Operators

Data Types

Script node input and output ports can use bytes, int, bool, and string. Lists and tuples are script-internal types.

Type Checking Rules

• A variable's type is determined at its first assignment and never changes. Reassigning a value of a different type is a compile-time error.
• No implicit type coercion: mixing int and bool, or int and bytes, is rejected. Use built-in functions such as to_int and to_bytes for explicit conversion.
• Conditions in if, elif, conditional expressions, and operands of and/or/not must have type bool.
• and and or use short-circuit evaluation.

Definite Assignment Analysis

Every local variable must be assigned before it is read, and every output port variable must be definitely assigned along all non-failing execution paths by the end of the script:

• An if/elif/else statement counts as assigning a variable only if every branch (including an explicit else) assigns it or terminates via fail(...) / return.
• Assignments inside a for loop body do not count as definitely assigned after the loop, because the loop body might execute zero times.

if n > 100:
    o = "big"
else:
    o = "small"

Omitting the else branch above causes a compile-time SCRIPT_OUTPUT_UNASSIGNED diagnostic.

Value Semantics

All values—including bytes and list[T]—have value semantics. Variable assignment and function argument passing behave as independent copies; mutating a byte or list element in one variable never mutates another variable:

a = h"00 00"
b = a
b[0] = 255

Operators

Operator precedence matches Python. Bitwise operators bind tighter than comparisons, so x & 0x80 != 0 parses as (x & 0x80) != 0. Chained comparisons (a < b < c) are rejected.

Operator Examples