cps-interpreter/src/interpreter/builtins.ts

import {
  type DenotableFunctionSignature,
  Environment,
  type Denotable,
} from '.';

const addUnaryIntegerOperationsTo = (env: Environment) => {
  const unaryIntegerOperationSignatures: DenotableFunctionSignature[] = [
    {
      arguments: ['int'],
      return: 'int',
    },
  ];

  for (const { name, fn } of [{ name: '~', fn: (a: number) => ~a }]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: unaryIntegerOperationSignatures,
        body: ({ value }: Denotable) => fn(value as number),
      },
    });
  }

  return env;
};

const addNumberComparisonOperationsTo = (env: Environment) => {
  const comparisonOperationsSignatures: DenotableFunctionSignature[] = [
    {
      arguments: [
        ['real', 'int'],
        ['real', 'int'],
      ],
      return: 'bool',
    },
  ];

  for (const { name, fn } of [
    { name: '<=', fn: (a: number, b: number) => (a <= b ? 1 : 0) },
    { name: '<', fn: (a: number, b: number) => (a < b ? 1 : 0) },
    { name: '>', fn: (a: number, b: number) => (a > b ? 1 : 0) },
    { name: '>=', fn: (a: number, b: number) => (a >= b ? 1 : 0) },
  ]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: comparisonOperationsSignatures,
        body: ({ value: a }: Denotable, { value: b }: Denotable) =>
          fn(a as number, b as number),
      },
    });
  }

  return env;
};

const addEqualityOperationsTo = (env: Environment) => {
  const equalityOperationSignatures: DenotableFunctionSignature[] = [
    {
      arguments: ['int', 'int'],
      return: 'bool',
    },
    {
      arguments: ['real', 'real'],
      return: 'bool',
    },
    {
      arguments: ['bool', 'bool'],
      return: 'bool',
    },
    {
      arguments: ['string', 'string'],
      return: 'bool',
    },
  ];

  for (const { name, fn } of [
    {
      name: '==',
      fn: (a: number | string, b: number | string) => (a === b ? 1 : 0),
    },
    {
      name: '!=',
      fn: (a: number | string, b: number | string) => (a !== b ? 1 : 0),
    },
  ]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: equalityOperationSignatures,
        body: ({ value: a }: Denotable, { value: b }: Denotable) =>
          fn(a as number | string, b as number | string),
      },
    });
  }

  return env;
};

const addBooleanAlgebraOperationsTo = (env: Environment) => {
  const binaryBooleanOps: DenotableFunctionSignature[] = [
    {
      arguments: ['bool', 'bool'],
      return: 'bool',
    },
  ];

  for (const { name, fn } of [
    { name: '||', fn: (a: number, b: number) => (a === 1 || b === 1 ? 1 : 0) },
    { name: '&&', fn: (a: number, b: number) => (a === 1 && b === 1 ? 1 : 0) },
  ]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: binaryBooleanOps,
        body: ({ value: a }: Denotable, { value: b }: Denotable) =>
          fn(a as number, b as number),
      },
    });
  }

  env.set('!', {
    type: 'function',
    value: {
      signatures: [
        {
          arguments: ['bool'],
          return: 'bool',
        },
      ],
      body: ({ value }: Denotable) => (value === 1 ? 0 : 1),
    },
  });

  return env;
};

const addBinaryIntegerOperationsTo = (env: Environment) => {
  const binaryIntegerOperationSignatures: DenotableFunctionSignature[] = [
    {
      arguments: ['int', 'int'],
      return: 'int',
    },
  ];

  for (const { name, fn } of [
    { name: '%', fn: (a: number, b: number) => a % b },
    { name: '>>', fn: (a: number, b: number) => a >> b },
    { name: '<<', fn: (a: number, b: number) => a << b },
    { name: '|', fn: (a: number, b: number) => a | b },
    { name: '^', fn: (a: number, b: number) => a ^ b },
  ]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: binaryIntegerOperationSignatures,
        body: ({ value: a }: Denotable, { value: b }: Denotable) =>
          fn(a as number, b as number),
      },
    });
  }

  return env;
};

const addBinaryArithmeticOperationsTo = (env: Environment) => {
  const binaryArithmeticSignatures: DenotableFunctionSignature[] = [
    {
      arguments: ['int', 'int'],
      return: 'int',
    },
    {
      arguments: [
        ['int', 'real'],
        ['int', 'real'],
      ],
      return: 'real',
    },
  ];

  for (const { name, fn } of [
    { name: '+', fn: (a: number, b: number) => a + b },
    { name: '-', fn: (a: number, b: number) => a - b },
    { name: '*', fn: (a: number, b: number) => a * b },
    { name: '/', fn: (a: number, b: number) => a / b },
    { name: '**', fn: (a: number, b: number) => a ** b },
  ]) {
    env.set(name, {
      type: 'function',
      value: {
        signatures: binaryArithmeticSignatures,
        body: ({ value: a }: Denotable, { value: b }: Denotable) =>
          fn(a as number, b as number),
      },
    });
  }

  return env;
};

const addIdentityFunctionTo = (env: Environment) => {
  env.set('id', {
    type: 'function',
    value: {
      signatures: [
        {
          arguments: ['null'],
          return: 'null',
        },
        {
          arguments: ['int'],
          return: 'int',
        },
        {
          arguments: ['real'],
          return: 'real',
        },
        {
          arguments: ['bool'],
          return: 'bool',
        },
        {
          arguments: ['string'],
          return: 'string',
        },
        {
          arguments: ['bytearray'],
          return: 'bytearray',
        },
        {
          arguments: ['function'],
          return: 'function',
        },
        {
          arguments: ['reference'],
          return: 'reference',
        },
      ],
      body: ({ value }: Denotable) => value,
    },
  });

  return env;
};

export const putBuiltinsOnEnvironemtn = (env: Environment) => {
  return [
    addBinaryArithmeticOperationsTo,
    addBinaryIntegerOperationsTo,
    addUnaryIntegerOperationsTo,
    addNumberComparisonOperationsTo,
    addBooleanAlgebraOperationsTo,
    addEqualityOperationsTo,
    addIdentityFunctionTo,
  ].reduce((acc, builtinsAdder) => builtinsAdder(acc), env);
};