sort-function-attributes.ts

import { NonterminalKind } from '@nomicfoundation/slang/cst';
import { TerminalNode } from '../slang-nodes/TerminalNode.js';

import type { SortableAttribute } from './types.d.ts';

const visibilityKeyWords = new Set([
  'external',
  'internal',
  'public',
  'private'
]);

const mutabilityKeyWords = new Set(['pure', 'constant', 'payable', 'view']);

export function sortFunctionAttributes(
  aVariant: SortableAttribute,
  bVariant: SortableAttribute
): number {
  const aIsString = aVariant instanceof TerminalNode;
  const bIsString = bVariant instanceof TerminalNode;

  // Both are strings
  if (aIsString && bIsString) {
    // Visibility First
    if (visibilityKeyWords.has(aVariant.value)) return -1;
    if (visibilityKeyWords.has(bVariant.value)) return 1;
    // State Mutability Second
    if (mutabilityKeyWords.has(aVariant.value)) return -1;
    if (mutabilityKeyWords.has(bVariant.value)) return 1;
    // Virtual keyword last
    return 0;
  }

  // Only one is a string
  if (aIsString) return -1;
  if (bIsString) return 1;

  // Both are nodes
  // OverrideSpecifiers before ModifierInvocation
  if (
    aVariant.kind === NonterminalKind.OverrideSpecifier &&
    bVariant.kind === NonterminalKind.ModifierInvocation
  )
    return -1;
  if (
    bVariant.kind === NonterminalKind.OverrideSpecifier &&
    aVariant.kind === NonterminalKind.ModifierInvocation
  )
    return 1;

  return 0;
}