Working on API surface.

packages/js/core/dist/document.cjs

@@ -1 +1,2 @@
-"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});const l=require("./parser.cjs");function s(a,i=" "){let e=null,t=l.LineData(),n=!1;async function r(){return e=await a(),e===null?n=!0:l.parseLine(e,t,i),{line:e,lineData:t,ended:n,next:r,current:u}}function u(){return{line:e,lineData:t,ended:n,next:r,current:u}}return{next:r,current:u}}exports.document=s;
+"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});const s=require("./parser.cjs");function a(i,u=" "){let r=s.createLineData(null,u);const t={ended:!1,clone(){return a(i.clone(),u)},async next(){if(r.line=await i.next(),r.line===null)return!0;s.parseLine(r)},current(){return t},line(){var e;return(e=r.line)==null?void 0:e.slice(r.offsetHead)},head(){var e;return(e=r.line)==null?void 0:e.slice(r.offsetHead,r.offsetTail)},tail(){var e;return(e=r.line)==null?void 0:e.slice(r.offsetTail)},async content(e=-1,n=[]){var l;return e===-1&&(e=r.level+1),await t.next()||r.level<e?n.join(`
+`):(n.push(((l=r.line)==null?void 0:l.slice(e))||""),t.content(e,n))},async seek(e,n=-1){return n===-1&&(n=r.level),await t.next()?!1:t.head()===e?t:r.level<n?!1:t.seek(e,n)}};return t}exports.useDocument=a;

packages/js/core/dist/document.js

@@ -1,14 +1,42 @@
-import { parseLine as a, LineData as o } from "./parser.js";
-function f(u, i = " ") {
-  let e = null, n = o(), t = !1;
-  async function r() {
-    return e = await u(), e === null ? t = !0 : a(e, n, i), { line: e, lineData: n, ended: t, next: r, current: l };
-  }
-  function l() {
-    return { line: e, lineData: n, ended: t, next: r, current: l };
-  }
-  return { next: r, current: l };
+import { parseLine as f, createLineData as s } from "./parser.js";
+function d(t, l = " ") {
+  let n = s(null, l);
+  const i = {
+    ended: !1,
+    clone() {
+      return d(t.clone(), l);
+    },
+    async next() {
+      if (n.line = await t.next(), n.line === null)
+        return !0;
+      f(n);
+    },
+    current() {
+      return i;
+    },
+    line() {
+      var e;
+      return (e = n.line) == null ? void 0 : e.slice(n.offsetHead);
+    },
+    head() {
+      var e;
+      return (e = n.line) == null ? void 0 : e.slice(n.offsetHead, n.offsetTail);
+    },
+    tail() {
+      var e;
+      return (e = n.line) == null ? void 0 : e.slice(n.offsetTail);
+    },
+    async content(e = -1, r = []) {
+      var u;
+      return e === -1 && (e = n.level + 1), await i.next() || n.level < e ? r.join(`
+`) : (r.push(((u = n.line) == null ? void 0 : u.slice(e)) || ""), i.content(e, r));
+    },
+    async seek(e, r = -1) {
+      return r === -1 && (r = n.level), await i.next() ? !1 : i.head() === e ? i : n.level < r ? !1 : i.seek(e, r);
+    }
+  };
+  return i;
 }
 export {
-  f as document
+  d as useDocument
 };

packages/js/core/dist/index.cjs

@@ -1 +1 @@
-"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});const e=require("./parser.cjs"),r=require("./document.cjs");exports.LineData=e.LineData;exports.parseLine=e.parseLine;exports.document=r.document;
+"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});const e=require("./parser.cjs"),r=require("./document.cjs");exports.createLineData=e.createLineData;exports.parseLine=e.parseLine;exports.useDocument=r.useDocument;

packages/js/core/dist/index.js

@@ -1,7 +1,7 @@
-import { LineData as r, parseLine as t } from "./parser.js";
-import { document as m } from "./document.js";
+import { createLineData as o, parseLine as t } from "./parser.js";
+import { useDocument as m } from "./document.js";
 export {
-  r as LineData,
-  m as document,
-  t as parseLine
+  o as createLineData,
+  t as parseLine,
+  m as useDocument
 };

packages/js/core/dist/parser.cjs

@@ -1 +1 @@
-"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});function s(){return{type:0,level:0,offsetHead:0,offsetTail:0}}function p(r,e,f=" "){if(typeof r!="string")throw new Error("'line' must be a string");if(typeof e!="object"||!e||typeof e.type!="number"||typeof e.level!="number")throw new Error("'lineData' must be an object with 'type' and 'level' integer properties");if(typeof f!="string"||f.length===0||f.length>1)throw new Error("'indent' must be a single-character string");let o=0,t=0;if(!r.length)e.type===1&&(t+=1),e.type===0&&(t=e.level),e.type=o,e.level=t,e.offsetHead=0,e.offsetTail=0;else{for(o=1;r[t]===f&&t<=e.level+1;)++t;for(e.type=o,e.level=t,e.offsetHead=t,e.offsetTail=t;r[e.offsetTail]&&r[e.offsetTail]!==" ";)++e.offsetTail}return e}exports.LineData=s;exports.parseLine=p;
+"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});function f(e=null,r=" "){return{line:e,indent:r,type:0,level:0,offsetHead:0,offsetTail:0}}function o(e){if(typeof e!="object"||!e||typeof e.type!="number"||typeof e.level!="number")throw new Error("'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties");if(typeof e.indent!="string"||e.indent.length===0||e.indent.length>1)throw new Error("'lineData.indent' must be a single-character string");if(typeof e.line!="string")throw new Error("'lineData.line' must be a string");let r=0,t=0;if(!e.line.length)e.type===1&&(t+=1),e.type===0&&(t=e.level),e.type=r,e.level=t,e.offsetHead=0,e.offsetTail=0;else{for(r=1;e.line[t]===e.indent&&t<=e.level+1;)++t;for(e.type=r,e.level=t,e.offsetHead=t,e.offsetTail=t;e.line[e.offsetTail]&&e.line[e.offsetTail]!==" ";)++e.offsetTail}return e}exports.createLineData=f;exports.parseLine=o;

packages/js/core/dist/parser.js

@@ -1,25 +1,25 @@
-function s() {
-  return { type: 0, level: 0, offsetHead: 0, offsetTail: 0 };
+function t(e = null, r = " ") {
+  return { line: e, indent: r, type: 0, level: 0, offsetHead: 0, offsetTail: 0 };
 }
-function p(r, e, t = " ") {
-  if (typeof r != "string")
-    throw new Error("'line' must be a string");
+function o(e) {
   if (typeof e != "object" || !e || typeof e.type != "number" || typeof e.level != "number")
-    throw new Error("'lineData' must be an object with 'type' and 'level' integer properties");
-  if (typeof t != "string" || t.length === 0 || t.length > 1)
-    throw new Error("'indent' must be a single-character string");
-  let o = 0, f = 0;
-  if (!r.length)
-    e.type === 1 && (f += 1), e.type === 0 && (f = e.level), e.type = o, e.level = f, e.offsetHead = 0, e.offsetTail = 0;
+    throw new Error("'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties");
+  if (typeof e.indent != "string" || e.indent.length === 0 || e.indent.length > 1)
+    throw new Error("'lineData.indent' must be a single-character string");
+  if (typeof e.line != "string")
+    throw new Error("'lineData.line' must be a string");
+  let r = 0, f = 0;
+  if (!e.line.length)
+    e.type === 1 && (f += 1), e.type === 0 && (f = e.level), e.type = r, e.level = f, e.offsetHead = 0, e.offsetTail = 0;
   else {
-    for (o = 1; r[f] === t && f <= e.level + 1; )
+    for (r = 1; e.line[f] === e.indent && f <= e.level + 1; )
       ++f;
-    for (e.type = o, e.level = f, e.offsetHead = f, e.offsetTail = f; r[e.offsetTail] && r[e.offsetTail] !== " "; )
+    for (e.type = r, e.level = f, e.offsetHead = f, e.offsetTail = f; e.line[e.offsetTail] && e.line[e.offsetTail] !== " "; )
       ++e.offsetTail;
   }
   return e;
 }
 export {
-  s as LineData,
-  p as parseLine
+  t as createLineData,
+  o as parseLine
 };

packages/js/core/dist/readers/js-string.cjs

@@ -0,0 +1,2 @@
+"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});function i(r,n=0){const t=Array.isArray(r)?r:r.split(`
+`),e={index:n-1,next:()=>(e.index++,e.index>=t.length?null:t[e.index]),clone:l=>i(r,l==null?n:e.index)};return e}exports.createStringReader=i;

packages/js/core/dist/readers/js-string.js

@@ -0,0 +1,12 @@
+function l(e, r = 0) {
+  const t = Array.isArray(e) ? e : e.split(`
+`), n = {
+    index: r - 1,
+    next: () => (n.index++, n.index >= t.length ? null : t[n.index]),
+    clone: (i) => l(e, i == null ? r : n.index)
+  };
+  return n;
+}
+export {
+  l as createStringReader
+};

packages/js/core/dist/readers/node-readline.cjs

@@ -0,0 +1 @@
+"use strict";Object.defineProperties(exports,{__esModule:{value:!0},[Symbol.toStringTag]:{value:"Module"}});const e={};function r(t){const a=e.createInterface({input:e.createReadStream(t,"utf-8")})[Symbol.asyncIterator]();return async()=>(await a.next()).value}exports.createReadlineReader=r;

packages/js/core/dist/readers/node-readline.js

@@ -0,0 +1,10 @@
+const e = {};
+function n(t) {
+  const a = e.createInterface({
+    input: e.createReadStream(t, "utf-8")
+  })[Symbol.asyncIterator]();
+  return async () => (await a.next()).value;
+}
+export {
+  n as createReadlineReader
+};

packages/js/core/package.json

@@ -4,8 +4,26 @@
   "license": "MIT",
   "type": "module",
   "exports": {
-    "import": "./dist/index.js",
-    "require": "./dist/index.cjs"
+    ".": {
+      "import": "./dist/index.js",
+      "require": "./dist/index.cjs"
+    },
+    "./parser": {
+      "import": "./dist/parser.js",
+      "require": "./dist/parser.cjs"
+    },
+    "./document": {
+      "import": "./dist/document.js",
+      "require": "./dist/document.cjs"
+    },
+    "./readers/node-readline": {
+      "import": "./dist/readers/node-readline.js",
+      "require": "./dist/readers/node-readline.cjs"
+    },
+    "./readers/js-string": {
+      "import": "./dist/readers/js-string.js",
+      "require": "./dist/readers/js-string.cjs"
+    }
   },
   "scripts": {
     "test": "vitest ./src",

packages/js/core/src/document.ts

@@ -1,20 +1,74 @@
-import { LineData, parseLine } from './parser'
+import type { Reader } from './readers/reader'
+import { createLineData, parseLine } from './parser'
 
-export function document (nextFn: () => Promise<string|null>, indent: string = ' ') {
-  let line: string|null = null
-  let lineData = LineData()
-  let ended = false
-
-  async function next() {
-    line = await nextFn()
-    if (line === null) ended = true
-    else parseLine(line, lineData, indent)
-    return { line, lineData, ended, next, current }
-  }
-
-  function current() {
-    return { line, lineData, ended, next, current }
-  }
-
-  return { next, current }
+type Document = {
+  ended: boolean,
+  clone: () => Document,
+  next: () => Promise<Document>
+  current: () => Document
+  line: () => string,
+  head: () => string,
+  tail: () => string,
+  content: (contentLevel: number, lines: string[]) => Promise<string>,
+  seek: (matchHead: string, contentLevel: number) => Promise<Document|false>
+}
+
+export function useDocument (reader: Reader, indent: string = ' '): Document {
+  let lineData = createLineData(null, indent)
+
+  const document = {
+    ended: false,
+
+    clone() {
+      return useDocument(reader.clone(), indent)
+    },
+
+    async next() {
+      lineData.line = await reader.next()
+      if (lineData.line === null) return true
+      else parseLine(lineData)
+    },
+
+    current() {
+      return document
+    },
+
+    line() {
+      return lineData.line?.slice(lineData.offsetHead)
+    },
+
+    head () {
+      return lineData.line?.slice(lineData.offsetHead, lineData.offsetTail)
+    },
+
+    tail () {
+      return lineData.line?.slice(lineData.offsetTail)
+    },
+
+    async content (contentLevel = -1, lines: string[] = []): Promise<string> {
+      if (contentLevel === -1) contentLevel = lineData.level + 1
+
+      const ended = await document.next()
+      if (ended) return lines.join('\n')
+
+      if (lineData.level < contentLevel) return lines.join('\n')
+
+      lines.push(lineData.line?.slice(contentLevel) || '')
+      return document.content(contentLevel, lines)
+    },
+
+    async seek (matchHead: string, contentLevel = -1): Promise<Document|false> {
+      if (contentLevel === -1) contentLevel = lineData.level
+
+      const ended = await document.next()
+      if (ended) return false
+
+      if (document.head() === matchHead) return document
+      if (lineData.level < contentLevel) return false
+
+      return document.seek(matchHead, contentLevel)
+    }
+  }
+
+  return document
 }

packages/js/core/src/parser.test.ts

@@ -1,145 +1,143 @@
 import { describe, expect, it } from 'vitest'
-import { LineData, parseLine } from './parser'
+import { createLineData, parseLine } from './parser'
 
 describe(`LineData`, () => {
   it(`is an object`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
     expect(lineData).toBeTypeOf(`object`)
   })
 
-  it(`has four properties`, () => {
-    const lineData = LineData()
-    expect(Object.keys(lineData).length).to.equal(4)
+  it(`has five properties`, () => {
+    const lineData = createLineData()
+    expect(Object.keys(lineData).length).to.equal(6)
+  })
+
+  it(`'line' is a string|null initialized to null`, () => {
+    const lineData = createLineData()
+    expect(lineData.level).to.equal(0)
   })
 
   it(`'type' is an integer initialized to zero`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
     expect(lineData.level).to.equal(0)
   })
 
   it(`'level' is an integer initialized to zero`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
     expect(lineData.type).to.equal(0)
   })
 
   it(`'offsetHead' is an integer initialized to zero`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
     expect(lineData.offsetHead).to.equal(0)
   })
 
   it(`'offsetTail' is an integer initialized to zero`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
     expect(lineData.offsetTail).to.equal(0)
   })
 })
 
 describe(`parseLine`, () => {
-  it(`Requres 'line' to be a string`, () => {
-    const lineData = LineData()
-    expect(() => parseLine(0, lineData)).toThrowError(`'line' must be a string`)
+  it(`Requres 'lineData' to be an object with a string line property and numeric level and type properties`, () => {
+    const lineData = createLineData()
     // @ts-ignore
-    expect(() => parseLine([], lineData)).toThrowError(`'line' must be a string`)
+    expect(() => parseLine(``, 0)).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine({}, lineData)).toThrowError(`'line' must be a string`)
+    expect(() => parseLine(``, [])).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(null, lineData)).toThrowError(`'line' must be a string`)
+    expect(() => parseLine(``, {})).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(true, lineData)).toThrowError(`'line' must be a string`)
+    expect(() => parseLine(``, null)).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(() => {}, lineData)).toThrowError(`'line' must be a string`)
-  })
-
-  it(`Requres 'lineData' to be an object with numeric level and type properties`, () => {
-    const lineData = LineData()
+    expect(() => parseLine(``, true)).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(``, 0)).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
+    expect(() => parseLine(``, () => {})).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(``, [])).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
+    expect(() => parseLine(``, { line: '', level: '', type: 0 })).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
     // @ts-ignore
-    expect(() => parseLine(``, {})).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
-    // @ts-ignore
-    expect(() => parseLine(``, null)).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
-    // @ts-ignore
-    expect(() => parseLine(``, true)).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
-    // @ts-ignore
-    expect(() => parseLine(``, () => {})).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
-    // @ts-ignore
-    expect(() => parseLine(``, { level: '', type: 0 })).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
-    // @ts-ignore
-    expect(() => parseLine(``, { level: 0, type: null })).toThrowError(`'lineData' must be an object with 'type' and 'level' integer properties`)
+    expect(() => parseLine(``, { line: '', level: 0, type: null })).toThrowError(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
   })
 
   it(`Requres 'indent' to be a single-character string`, () => {
-    const lineData = LineData()
+    const lineData = createLineData()
+    lineData.line = ``
     // @ts-ignore
-    expect(() => parseLine(``, lineData, 0)).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = 0
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
     // @ts-ignore
-    expect(() => parseLine(``, lineData, [])).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = []
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
     // @ts-ignore
-    expect(() => parseLine(``, lineData, {})).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = {}
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
     // @ts-ignore
-    expect(() => parseLine(``, lineData, null)).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = null
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
     // @ts-ignore
-    expect(() => parseLine(``, lineData, true)).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = true
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
     // @ts-ignore
-    expect(() => parseLine(``, lineData, () => {})).toThrowError(`'indent' must be a single-character string`)
-    expect(() => parseLine(``, lineData, `  `)).toThrowError(`'indent' must be a single-character string`)
+    lineData.indent = () => {}
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
+    lineData.indent = `  `
+    expect(() => parseLine(lineData)).toThrowError(`'lineData.indent' must be a single-character string`)
   })
 
   it(`Handles a blank line at indent level 0`, () => {
     const line = ``
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 0, level: 0, offsetHead: 0, offsetTail: 0 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 0, level: 0, offsetHead: 0, offsetTail: 0 })
   })
 
   it(`Handles a line with a single space at indent level 1`, () => {
     const line = ` `
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 1, level: 1, offsetHead: 1, offsetTail: 1 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 1, level: 1, offsetHead: 1, offsetTail: 1 })
   })
 
   it(`Handles a line with two spaces`, () => {
     const line = `  `
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 1, level: 2, offsetHead: 2, offsetTail: 2 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 1, level: 2, offsetHead: 2, offsetTail: 2 })
   })
 
   it(`Handles a normal line at indent level 0`, () => {
     const line = `line 1`
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 1, level: 0, offsetHead: 0, offsetTail: 4 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 1, level: 0, offsetHead: 0, offsetTail: 4 })
   })
 
   it(`Handles a normal line at indent level 1`, () => {
     const line = ` line 1`
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 1, level: 1, offsetHead: 1, offsetTail: 5 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 1, level: 1, offsetHead: 1, offsetTail: 5 })
   })
 
   it(`Handles a normal line at indent level 2`, () => {
     const line = `  line 1`
-    const lineData = LineData()
-    parseLine(line, lineData)
-    expect(lineData).to.deep.equal({ type: 1, level: 2, offsetHead: 2, offsetTail: 6 })
+    const lineData = createLineData(line)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: ` `, type: 1, level: 2, offsetHead: 2, offsetTail: 6 })
   })
 
   it(`Handles a normal line at indent level 1 indented with tabs`, () => {
     const line = `\tline 1`
-    const lineData = LineData()
-    parseLine(line, lineData, `\t`)
-    expect(lineData).to.deep.equal({ type: 1, level: 1, offsetHead: 1, offsetTail: 5 })
+    const lineData = createLineData(line, `\t`)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: `\t`, type: 1, level: 1, offsetHead: 1, offsetTail: 5 })
   })
 
   it(`Handles a normal line at indent level 2 indented with tabs`, () => {
     const line = `\t\tline 1`
-    const lineData = LineData()
-    parseLine(line, lineData, `\t`)
-    expect(lineData).to.deep.equal({ type: 1, level: 2, offsetHead: 2, offsetTail:  6})
+    const lineData = createLineData(line, `\t`)
+    parseLine(lineData)
+    expect(lineData).to.deep.equal({ line, indent: `\t`, type: 1, level: 2, offsetHead: 2, offsetTail:  6})
   })
 
   it(`Nests a normal line under a preceding normal line`, () => {
@@ -148,15 +146,16 @@ describe(`parseLine`, () => {
       ' line 2'
     ]
 
-    const lineData = LineData()
+    const lineData = createLineData()
     const results = lines.map(line => {
-      parseLine(line, lineData)
+      lineData.line = line
+      parseLine(lineData)
       return {...lineData}
     })
 
     expect(results).to.deep.equal([
-      { type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
-      { type: 1, level: 1, offsetHead: 1, offsetTail: 5 }
+      { line: lines[0], indent: ' ', type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
+      { line: lines[1], indent: ' ', type: 1, level: 1, offsetHead: 1, offsetTail: 5 }
     ])
   })
 
@@ -168,17 +167,18 @@ describe(`parseLine`, () => {
       ' line 4',
     ]
 
-    const lineData = LineData()
+    const lineData = createLineData()
     const results = lines.map(line => {
-      parseLine(line, lineData)
+      lineData.line = line
+      parseLine(lineData)
       return {...lineData}
     })
 
     expect(results).to.deep.equal([
-      { type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
-      { type: 1, level: 1, offsetHead: 1, offsetTail: 5 },
-      { type: 1, level: 1, offsetHead: 1, offsetTail: 5 },
-      { type: 1, level: 1, offsetHead: 1, offsetTail: 5 }
+      { line: lines[0], indent: ' ', type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
+      { line: lines[1], indent: ' ', type: 1, level: 1, offsetHead: 1, offsetTail: 5 },
+      { line: lines[2], indent: ' ', type: 1, level: 1, offsetHead: 1, offsetTail: 5 },
+      { line: lines[3], indent: ' ', type: 1, level: 1, offsetHead: 1, offsetTail: 5 }
     ])
   })
 
@@ -188,15 +188,16 @@ describe(`parseLine`, () => {
       ''
     ]
 
-    const lineData = LineData()
+    const lineData = createLineData()
     const results = lines.map(line => {
-      parseLine(line, lineData)
+      lineData.line = line
+      parseLine(lineData)
       return {...lineData}
     })
 
     expect(results).to.deep.equal([
-      { type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
-      { type: 0, level: 1, offsetHead: 0, offsetTail: 0 }
+      { line: lines[0], indent: ' ', type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
+      { line: lines[1], indent: ' ', type: 0, level: 1, offsetHead: 0, offsetTail: 0 }
     ])
   })
 
@@ -208,24 +209,25 @@ describe(`parseLine`, () => {
       '',
     ]
 
-    const lineData = LineData()
+    const lineData = createLineData()
     const results = lines.map(line => {
-      parseLine(line, lineData)
+      lineData.line = line
+      parseLine(lineData)
       return {...lineData}
     })
 
     expect(results).to.deep.equal([
-      { type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
-      { type: 0, level: 1, offsetHead: 0, offsetTail: 0 },
-      { type: 0, level: 1, offsetHead: 0, offsetTail: 0 },
-      { type: 0, level: 1, offsetHead: 0, offsetTail: 0 }
+      { line: lines[0], indent: ' ', type: 1, level: 0, offsetHead: 0, offsetTail: 4 },
+      { line: lines[1], indent: ' ', type: 0, level: 1, offsetHead: 0, offsetTail: 0 },
+      { line: lines[2], indent: ' ', type: 0, level: 1, offsetHead: 0, offsetTail: 0 },
+      { line: lines[3], indent: ' ', type: 0, level: 1, offsetHead: 0, offsetTail: 0 }
     ])
   })
 
   it(`Handle head and tail matching for lines with head and tail`, () => {
     const line = `  head tail1 tail2 tail3`
-    const lineData = LineData()
-    parseLine(line, lineData)
+    const lineData = createLineData(line)
+    parseLine(lineData)
 
     const head = line.slice(lineData.offsetHead, lineData.offsetTail)
     const tail = line.slice(lineData.offsetTail + 1)
@@ -235,8 +237,8 @@ describe(`parseLine`, () => {
 
   it(`Handle head and tail matching for lines with head but no tail`, () => {
     const line = `  head`
-    const lineData = LineData()
-    parseLine(line, lineData)
+    const lineData = createLineData(line)
+    parseLine(lineData)
 
     const head = line.slice(lineData.offsetHead, lineData.offsetTail)
     const tail = line.slice(lineData.offsetTail + 1)
@@ -246,8 +248,8 @@ describe(`parseLine`, () => {
 
   it(`Handle head and tail matching for lines with head and trailing space`, () => {
     const line = `  head `
-    const lineData = LineData()
-    parseLine(line, lineData)
+    const lineData = createLineData(line)
+    parseLine(lineData)
 
     const head = line.slice(lineData.offsetHead, lineData.offsetTail)
     const tail = line.slice(lineData.offsetTail + 1)

packages/js/core/src/parser.ts

@@ -1,23 +1,25 @@
-type LineData = {
+export type LineData = {
+  line: string|null;
+  indent: string;
   type: number;
   level: number;
   offsetHead: number;
   offsetTail: number;
 }
 
-export function LineData(): LineData {
-  return { type: 0, level: 0, offsetHead: 0, offsetTail: 0 }
+export function createLineData(line: string|null = null, indent: string = ' '): LineData {
+  return { line, indent, type: 0, level: 0, offsetHead: 0, offsetTail: 0 }
 }
 
-export function parseLine(line: string, lineData: LineData, indent: string = ' '): LineData {
-  if (typeof line !== 'string') throw new Error(`'line' must be a string`)
-  if ((typeof lineData !== 'object' || !lineData) || typeof lineData.type !== 'number' || typeof lineData.level !== 'number') throw new Error(`'lineData' must be an object with 'type' and 'level' integer properties`)
-  if (typeof indent !== 'string' || indent.length === 0 || indent.length > 1) throw new Error(`'indent' must be a single-character string`)
+export function parseLine(lineData: LineData): LineData {
+  if ((typeof lineData !== 'object' || !lineData) || typeof lineData.type !== 'number' || typeof lineData.level !== 'number') throw new Error(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
+  if (typeof lineData.indent !== 'string' || lineData.indent.length === 0 || lineData.indent.length > 1) throw new Error(`'lineData.indent' must be a single-character string`)
+  if (typeof lineData.line !== 'string') throw new Error(`'lineData.line' must be a string`)
 
   let type = 0
   let level = 0
 
-  if (!line.length) {
+  if (!lineData.line.length) {
     if (lineData.type === 1) level += 1
     if (lineData.type === 0) level = lineData.level
 
@@ -28,13 +30,13 @@ export function parseLine(line: string, lineData: LineData, indent: string = ' '
   } else {
     type = 1
 
-    while (line[level] === indent && level <= lineData.level + 1) ++level
+    while (lineData.line[level] === lineData.indent && level <= lineData.level + 1) ++level
     lineData.type = type
     lineData.level = level
     lineData.offsetHead = level
     lineData.offsetTail = level
 
-    while (line[lineData.offsetTail] && line[lineData.offsetTail] !== ' ') ++lineData.offsetTail
+    while (lineData.line[lineData.offsetTail] && lineData.line[lineData.offsetTail] !== ' ') ++lineData.offsetTail
   }
 
   return lineData

packages/js/core/src/readers/js-string.ts

@@ -0,0 +1,17 @@
+import type { Reader } from './reader'
+
+export function createStringReader(doc: string|string[], index = 0): Reader {
+  const lines = Array.isArray(doc) ? doc : doc.split('\n')
+
+  const reader = {
+    index: index - 1,
+    next: () => {
+      reader.index++
+      if (reader.index >= lines.length) return null
+      return lines[reader.index]
+    },
+    clone: (startIndex?: number) => createStringReader(doc, startIndex == null ? index : reader.index)
+  }
+
+  return reader
+}

packages/js/core/src/readers/node-readline.ts

@@ -0,0 +1,10 @@
+import fs from 'node:fs'
+import readline from 'node:readline/promises'
+
+export function createReadlineReader(path: string): () => Promise<string|null> {
+  const it = readline.createInterface({
+    input: fs.createReadStream(path, 'utf-8'),
+  })[Symbol.asyncIterator]()
+
+  return async () => (await it.next()).value
+}

packages/js/core/src/readers/reader.ts

@@ -0,0 +1,5 @@
+export type Reader = {
+  index: number,
+  next: () => string|null|Promise<string|null>,
+  clone: (startIndex?: number) => Reader
+}

packages/js/core/vite.config.js

@@ -1,16 +1,17 @@
 // vite.config.js
-import { resolve } from 'path'
 import { defineConfig } from 'vite'
 
 export default defineConfig({
   build: {
     lib: {
       // Could also be a dictionary or array of multiple entry points
-      entry: [
-        resolve(__dirname, 'src/index.ts'),
-        resolve(__dirname, 'src/document.ts'),
-        resolve(__dirname, 'src/parser.ts'),
-      ]
+      entry: {
+        'index': 'src/index.ts',
+        'document': 'src/document.ts',
+        'parser': 'src/parser.ts',
+        'readers/js-string': 'src/readers/js-string.ts',
+        'readers/node-readline': 'src/readers/node-readline.ts',
+      }
     }
   }
 })