nexpr/txcommand.js

## txcommand.js
const snip_start_marker = "@"
const snip_end_marker = ";"
const accept_sources = [
	"textarea", "input[type=text]"
]
const snimap = {
	"test": "てすと",
	"run"(elem){
		console.log(elem)
	},
	"tabindent"(elem){
		const pre = elem.value
		elem.value = pre.replace(/^ {4,}/g, e =>
			"\t".repeat(~~(e.length / 4)) + " ".repeat(e.length % 4))
		if(elem.value !== pre){
			elem.selectionStart = elem.selectionEnd = elem.value.length
		}
	},
	"doctype"(elem){
		const text = `<!doctype html>\n<meta charset="utf-8">\n`
		elem.value = strinsert(elem.value, elem.selectionStart, text)
		setCaret(elem, elem.selectionStart + text.length)
	},
	"expand"(elem){
		let start
		{
			let i = elem.selectionStart
			while(true){
				const char = elem.value.charAt(--i)
				if(char === "\n" || char === ""){
					start = i + 1
					break
				}
			}
		}
		const snivar = elem.value.slice(start, elem.selectionStart)
		const matched = snivar.trim().match(/^(-?\d+) *\: *(-?\d+)$/)
		if(!matched) return

		const rstart = ~~matched[1]
		const rend = ~~matched[2]
		if(rstart > rend) return

		const text = Array.from(Array(rend - rstart + 1), (e, i) => rstart + i).join("\n")
		replaceElementText(elem, text, start, elem.selectionStart)
	}
}

function strcut(str, start, end){
	return str.substr(0, start) + str.substr(end)
}

function strinsert(str, index, text){
	return str.substr(0, index) + text + str.substr(index)
}

function setCaret(elem, start, end = start){
	elem.selectionStart = start
	elem.selectionEnd = end
}

function replaceElementText(elem, text, start, end = start){
	const inipos = elem.selectionStart

	elem.value = strinsert(strcut(elem.value, start, end), start, text)

	if(inipos >= start){
		const newpos = start + text.length
		setCaret(elem, newpos)
	}
}

function checkSnip(elem){
	if(!(elem.selectionStart === elem.selectionEnd && elem.selectionStart)){
		return false
	}
	const end = elem.selectionStart
	let start
	{
		let i = elem.selectionStart
		while(true){
			const char = elem.value.charAt(--i)
			if(char === "\n" || char === ""){
				return false
			}
			if(char === snip_start_marker){
				start = i
				break
			}
		}
	}
	const snip = elem.value.slice(start + 1, end)
	if(!(snip in snimap)){
		return false
	}

	return {start, end, key: snip}
}

window.addEventListener("keydown", eve => {
	const elem = eve.target
	const do_handle = accept_sources.some(e => eve.target.matches(e))
		&& eve.key === snip_end_marker
	if(!do_handle) return

	const snip = checkSnip(elem)
	if(!snip) return

	const action = snimap[snip.key]

	elem.value = strcut(elem.value, snip.start, snip.end)
	setCaret(elem, snip.start)

	if(typeof action === "string"){
		elem.value = strinsert(elem.value, snip.start, action)
		setCaret(elem, snip.start + action.length)
	}else{
		action(elem)
	}

	eve.preventDefault()
	eve.stopPropagation()
}, true)
	const snip_start_marker = "@"
	const snip_end_marker = ";"
	const accept_sources = [
	"textarea", "input[type=text]"
	]
	const snimap = {
	"test": "てすと",
	"run"(elem){
	console.log(elem)
	},
	"tabindent"(elem){
	const pre = elem.value
	elem.value = pre.replace(/^ {4,}/g, e =>
	"\t".repeat(~~(e.length / 4)) + " ".repeat(e.length % 4))
	if(elem.value !== pre){
	elem.selectionStart = elem.selectionEnd = elem.value.length
	}
	},
	"doctype"(elem){
	const text = `<!doctype html>\n<meta charset="utf-8">\n`
	elem.value = strinsert(elem.value, elem.selectionStart, text)
	setCaret(elem, elem.selectionStart + text.length)
	},
	"expand"(elem){
	let start
	{
	let i = elem.selectionStart
	while(true){
	const char = elem.value.charAt(--i)
	if(char === "\n" \|\| char === ""){
	start = i + 1
	break
	}
	}
	}
	const snivar = elem.value.slice(start, elem.selectionStart)
	const matched = snivar.trim().match(/^(-?\d+) \: (-?\d+)$/)
	if(!matched) return

	const rstart = ~~matched[1]
	const rend = ~~matched[2]
	if(rstart > rend) return

	const text = Array.from(Array(rend - rstart + 1), (e, i) => rstart + i).join("\n")
	replaceElementText(elem, text, start, elem.selectionStart)
	}
	}

	function strcut(str, start, end){
	return str.substr(0, start) + str.substr(end)
	}

	function strinsert(str, index, text){
	return str.substr(0, index) + text + str.substr(index)
	}

	function setCaret(elem, start, end = start){
	elem.selectionStart = start
	elem.selectionEnd = end
	}

	function replaceElementText(elem, text, start, end = start){
	const inipos = elem.selectionStart

	elem.value = strinsert(strcut(elem.value, start, end), start, text)

	if(inipos >= start){
	const newpos = start + text.length
	setCaret(elem, newpos)
	}
	}

	function checkSnip(elem){
	if(!(elem.selectionStart === elem.selectionEnd && elem.selectionStart)){
	return false
	}
	const end = elem.selectionStart
	let start
	{
	let i = elem.selectionStart
	while(true){
	const char = elem.value.charAt(--i)
	if(char === "\n" \|\| char === ""){
	return false
	}
	if(char === snip_start_marker){
	start = i
	break
	}
	}
	}
	const snip = elem.value.slice(start + 1, end)
	if(!(snip in snimap)){
	return false
	}

	return {start, end, key: snip}
	}

	window.addEventListener("keydown", eve => {
	const elem = eve.target
	const do_handle = accept_sources.some(e => eve.target.matches(e))
	&& eve.key === snip_end_marker
	if(!do_handle) return

	const snip = checkSnip(elem)
	if(!snip) return

	const action = snimap[snip.key]

	elem.value = strcut(elem.value, snip.start, snip.end)
	setCaret(elem, snip.start)

	if(typeof action === "string"){
	elem.value = strinsert(elem.value, snip.start, action)
	setCaret(elem, snip.start + action.length)
	}else{
	action(elem)
	}

	eve.preventDefault()
	eve.stopPropagation()
	}, true)