feat: repeat quantifier (#11)

Author: okwasniewski

src/__tests__/compiler.test.tsx

@@ -1,5 +1,5 @@
 import { buildPattern, buildRegex } from '../compiler';
-import { oneOrMore, optionally, one, zeroOrMore } from '../quantifiers';
+import { oneOrMore, optionally, one, zeroOrMore, repeat } from '../quantifiers';
 
 test('basic quantifies', () => {
   expect(buildPattern('a')).toEqual('a');
@@ -12,6 +12,8 @@ test('basic quantifies', () => {
   expect(buildPattern('a', oneOrMore('bc'))).toEqual('a(?:bc)+');
   expect(buildPattern('a', oneOrMore('bc'))).toEqual('a(?:bc)+');
 
+  expect(buildPattern('a', repeat({ min: 1, max: 5 }, 'b'))).toEqual('ab{1,5}');
+
   expect(buildPattern('a', zeroOrMore('b'))).toEqual('ab*');
   expect(buildPattern('a', zeroOrMore('bc'))).toEqual('a(?:bc)*');
   expect(buildPattern('a', zeroOrMore('bc'))).toEqual('a(?:bc)*');

src/__tests__/repeat.test.tsx

@@ -0,0 +1,15 @@
+import { buildPattern } from '../compiler';
+import { repeat, zeroOrMore, oneOrMore } from '../quantifiers';
+
+test('"repeat" quantifier', () => {
+  expect(buildPattern('a', repeat({ min: 1, max: 5 }, 'b'))).toEqual('ab{1,5}');
+  expect(buildPattern('a', repeat({ min: 1 }, 'b'))).toEqual('ab{1,}');
+  expect(buildPattern('a', repeat({ count: 1 }, 'b'))).toEqual('ab{1}');
+
+  expect(buildPattern('a', repeat({ count: 1 }, 'a', zeroOrMore('b')))).toEqual(
+    'a(?:ab*){1}'
+  );
+  expect(
+    buildPattern(repeat({ count: 5 }, 'text', ' ', oneOrMore('d')))
+  ).toEqual('(?:text d+){5}');
+});

src/compiler.ts

@@ -1,5 +1,6 @@
 import type { RegexElement } from './types';
 import { compilers as quantifiers } from './quantifiers';
+import { compileRepeat } from './quantifiers/repeat';
 
 /**
  * Generate RegExp object for elements.
@@ -32,11 +33,16 @@ function compileSingle(elements: RegexElement): string {
     return elements;
   }
 
+  const compiledChildren = compileList(elements.children);
+
+  if (elements.type === 'repeat') {
+    return compileRepeat(elements.config, compiledChildren);
+  }
+
   const elementCompiler = quantifiers[elements.type];
   if (!elementCompiler) {
     throw new Error(`Unknown elements type ${elements.type}`);
   }
 
-  const children = compileList(elements.children);
-  return elementCompiler(children);
+  return elementCompiler(compiledChildren);
 }

src/quantifiers.ts renamed to src/quantifiers/index.ts

@@ -3,10 +3,12 @@ import type {
   OneOrMore,
   Optionally,
   RegexElement,
+  Repeat,
+  RepeatConfig,
   ZeroOrMore,
-} from './types';
-import type { CompilerMap } from './types-internal';
-import { wrapGroup } from './utils';
+} from '../types';
+import type { CompilerMap } from '../types-internal';
+import { wrapGroup } from '../utils';
 
 export function oneOrMore(...children: RegexElement[]): OneOrMore {
   return {
@@ -36,9 +38,20 @@ export function zeroOrMore(...children: RegexElement[]): ZeroOrMore {
   };
 }
 
+export function repeat(
+  config: RepeatConfig,
+  ...children: RegexElement[]
+): Repeat {
+  return {
+    type: 'repeat',
+    children,
+    config,
+  };
+}
+
 export const compilers = {
   one: (compiledChildren) => compiledChildren,
   oneOrMore: (compiledChildren) => `${wrapGroup(compiledChildren)}+`,
-  optionally: (compiledChildren: string) => `${wrapGroup(compiledChildren)}?`,
-  zeroOrMore: (compiledChildren: string) => `${wrapGroup(compiledChildren)}*`,
+  optionally: (compiledChildren) => `${wrapGroup(compiledChildren)}?`,
+  zeroOrMore: (compiledChildren) => `${wrapGroup(compiledChildren)}*`,
 } satisfies CompilerMap;

src/quantifiers/repeat.ts

@@ -0,0 +1,17 @@
+import type { RepeatConfig } from '../types';
+import { wrapGroup } from '../utils';
+
+export function compileRepeat(
+  config: RepeatConfig,
+  compiledChildren: string
+): string {
+  if ('count' in config && typeof config.count === 'number') {
+    return `${wrapGroup(compiledChildren)}{${config.count}}`;
+  }
+
+  if ('min' in config && typeof config.min === 'number') {
+    return `${wrapGroup(compiledChildren)}{${config.min},${config?.max ?? ''}}`;
+  }
+
+  return `${wrapGroup(compiledChildren)}`;
+}

src/types.ts

@@ -1,6 +1,11 @@
 export type RegexElement = string | RegexQuantifier;
 
-export type RegexQuantifier = One | OneOrMore | Optionally | ZeroOrMore;
+export type RegexQuantifier =
+  | One
+  | OneOrMore
+  | Optionally
+  | ZeroOrMore
+  | Repeat;
 
 // Quantifiers
 export type One = {
@@ -18,6 +23,18 @@ export type Optionally = {
   children: RegexElement[];
 };
 
+export type RepeatConfig =
+  | { min: number; max?: number }
+  | {
+      count: number;
+    };
+
+export type Repeat = {
+  type: 'repeat';
+  children: RegexElement[];
+  config: RepeatConfig;
+};
+
 export type ZeroOrMore = {
   type: 'zeroOrMore';
   children: RegexElement[];