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Malte UblandClaude Opus 5.5
24c54fc5d3
`Int32` from @scriptc/types now also annotates the element type of a declared number array (`Int32[]`, `readonly Int32[]`, `Array<Int32>`, `ReadonlyArray<Int32>`) on parameters, variables, class instance fields and function results. The contract promises that every element stored into the array, through any reference, is an int32 by construction. contracts/int32-elements.ts checks it over a whole-program flow graph of the places array references live (locals, parameters, globals, results, class field families, record fields, container element slots), with one node per allocation and per opaque origin. Allocations that can reach an annotated slot are constrained and every element store into an array that may be constrained must be range-proven an int32 (SC7002); element copies constrain their sources by fixpoint; arrays from or escaping to code the IR does not show refuse the contract (SC7003). Slots only constrained arrays reach are recorded as IrContracts.int32Elements. Element reads that find a value through those slots carry the int32 range, `getNumber` reads are integer-or-NaN operands of wrapping sums, and ToInt32 of any integer-or-NaN operand is branch-free. Holes, missing indices and length changes keep their JavaScript behavior. Integer kernels over a 2^20-element array: `(s + a[i]) | 0` 1086 -> 175 ms, `(Math.imul(h, 31) + a[i]) | 0` 602 -> 150 ms, prefix sums 575 -> 155 ms; programs without the annotation compile to identical binaries. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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@scriptc/types
Contract types for scriptc: type aliases with no meaning in TypeScript or Node.js that scriptc checks as extra promises. Import them with import type, which TypeScript erases, so Node.js never loads this package.
import type { Immutable, Int32, NoThrow } from "@scriptc/types";
const KEYWORDS: Immutable<Map<string, number>> = new Map([["const", 1]]);
class Token {
pos: Int32 = 0;
}
function isLetter(ch: number): NoThrow<boolean> {
return (ch >= 97 && ch <= 122) || (ch >= 65 && ch <= 90);
}
Contracts
NoThrow<T>on a function's return type: the function never throws. Callers need no exception checks.Int32on a parameter, variable, class instance field or function result: every stored value is a signed 32-bit integer by construction (an integer literal in range, a bitwise result such asx | 0,Math.imul, anotherInt32, or arithmetic scriptc can bound). The slot is stored as a 32-bit integer.Int32[](alsoreadonly Int32[],Array<Int32>) on a parameter, variable, class instance field or function result of typenumber[]: every element stored into the array, through any reference, is an int32 by construction. Element reads that find a value are int32s, so integer arithmetic over them runs in 32-bit operations; holes and missing indices still read asundefined.Immutable<T>on a parameter, variable, class instance field or function result: a deep read-only view, and no code writes to the value through any reference. A module constant built from literals becomes immortal data.Acyclicon a class (class C implements Acyclic), interface (interface I extends Acyclic) or object type alias (type T = Acyclic<{ ... }>): no chain of references can lead from such an object back to itself. Its objects carry no cycle-collector header.ProgramLifetimein a class'simplementsclause: instances of the class and its subclasses are never freed, so scriptc skips reference counting and cycle collection for them. Memory only: discarded instances are not reclaimed.
scriptc proves each contract or rejects the program with a diagnostic (SC7001-SC7008) that explains why it does not hold. A program that compiles behaves exactly as under Node.js. See https://scriptc.dev/docs/contracts.