regex-lab

1import { clean, text, code, row, frame, bar, pretty, bounded, entries, safePath } from './ui.js'
2const ID = "regex-lab"
3let pattern="APP-\\d+"
4let flags="g"
5let source="Fix APP-123 before APP-456"
6let output=""
7
8
9function transform() {
10 bounded(source,2000);bounded(pattern,160)
11 if(!/^[gimsuy]*$/.test(flags))throw new Error('Flags must be g, i, m, s, u, or y.')
12 // Use a predictable subset rather than executing arbitrary backtracking patterns.
13 let inClass=false,repeat=0
14 for(let i=0;i<pattern.length;i++) {
15  const c=pattern[i]
16  if(c==='\\') {
17   const escape=pattern[++i]
18   if(/[1-9k]/.test(escape||''))throw new Error('Backreferences are refused.')
19   continue
20  }
21  if(c==='[')inClass=true
22  else if(c===']')inClass=false
23  else if(!inClass) {
24   if('()|'.includes(c))throw new Error('Groups and alternation are outside the supported subset.')
25   if('*+?{'.includes(c) && ++repeat>1)throw new Error('Use at most one repetition operator in this lab.')
26  }
27 }
28 const re=new RegExp(pattern,flags.includes('g')?flags:flags+'g')
29 const found=Array.from(source.matchAll(re)).slice(0,40)
30 return found.length+' matches\n\n'+found.map(m=>'['+m.index+', '+(m.index+m[0].length)+') '+m[0]).join('\n')
31}
32
33async function calculate($) {
34 try { output=await transform() } catch(error){output='Invalid input: '+error.message}
35 $.ui.invalidate('ui.render')
36}
37
38export function register(on) {
39  on('session.start', async ($, e, next) => {
40
41    await $.command.register({name:ID, description:"Test a regular expression against text and see matched ranges.", immediate:true, argumentHint:""})
42    return next(e)
43  })
44  on('command.run', {command:"regex-lab"}, async ($, e) => {
45    await calculate($)
46    await $.ui.open({id:ID,title:"Regex Lab",focus:true,closeOnEscape:true})
47    return {}
48  })
49
50  on('ui.render', {component:'Pane'}, async ($, e, next) => {
51    if(e.requestId !== ID) return next(e)
52    const E = $.ui.resolve(e)
53    try {
54      const body = await draw($, E)
55      return frame(E,"Regex Lab","Test a regular expression against text and see matched ranges.",body)
56    } catch(error) {
57      return frame(E,"Regex Lab",'Unable to inspect this data.',[text(E,error.message,{color:'yellow'}),E.Button({key:'refresh',label:'Refresh',onPress:()=>$.ui.invalidate('ui.render')})])
58    }
59  })
60}
61async function draw($, E) {
62  const refresh = E.Button({key:'refresh',label:'Refresh',hotkey:'r',plain:true,onPress:()=>$.ui.invalidate('ui.render')})
63return [text(E,'Supported subset: character classes, anchors, escapes, and one repetition; no groups or alternation.'),E.Input({key:"pattern",label:"Pattern",value:clean(pattern),submitLabel:'apply',onSubmit:async(v)=>{pattern=v;await calculate($)}}),
64E.Input({key:"flags",label:"Flags",value:clean(flags),submitLabel:'apply',onSubmit:async(v)=>{flags=v;await calculate($)}}),
65E.Input({key:"source",label:"Text",value:clean(source),submitLabel:'apply',onSubmit:async(v)=>{source=v;await calculate($)}}),code(E,output),E.Button({key:'copy',label:'Copy result',onPress:async()=>{const r=await $.ui.copy({text:output});if(!r.isCopied)$.ui.toast('Clipboard unavailable.')}})]
66}
67

1// Pure UI helpers. No engine access; each plugin contains its own copy.
2export function clean(value, limit = 9000) {
3  return String(value ?? '').replace(/[\u0000-\u0008\u000b\u000c\u000e-\u001f\u007f-\u009f]/g, '').slice(0, limit)
4}
5export function text(E, value, props = {}) {
6  return E.Text({ ...props, children: [clean(value)] })
7}
8export function code(E, value, language = 'text') {
9  return E.Code({ source: clean(value), language })
10}
11export function row(E, children) {
12  return E.Box({ flexDirection: 'row', columnGap: 2, flexWrap: 'wrap', children })
13}
14export function frame(E, title, subtitle, children) {
15  return E.Box({ flexDirection: 'column', gap: 1, children: [
16    text(E, title, { bold: true, color: 'cyan' }),
17    text(E, subtitle, { dimColor: true }), ...children,
18  ] })
19}
20export function bar(percent, width = 24) {
21  const p = Math.max(0, Math.min(100, Number(percent) || 0))
22  const n = Math.round(p / 100 * width)
23  return '[' + '#'.repeat(n) + '-'.repeat(width - n) + '] ' + p.toFixed(1) + '%'
24}
25export function pretty(value) { return JSON.stringify(value, null, 2) }
26export function bounded(value, max = 9000) {
27  if (value.length > max) throw new Error('Input exceeds ' + max + ' characters. Use a smaller selection.')
28  return value
29}
30export function entries(value) { return value && typeof value === 'object' ? Object.entries(value) : [] }
31export function safePath(value) {
32  const path = value.trim()
33  if (!path || path.startsWith('-') || /[\x00-\x1f]/.test(path)) throw new Error('Enter a path without control characters or leading flags.')
34  return path
35}
36