sort csv in mml

csv-sort.mml

#! /bin/mml

// sort csv by a column

import (
	csvparser "mml/parser/csv"
	csvtemplate "mml/template/csv"
	"mml/function"
	"mml/lists"
	"mml/log"
	"mml/os"
	"mml/sort"
	"mml/values"
)

let columnIndex values.convertOrAbort(
	values.stringToInt
	"expected one number argument"
	lists.atOrDefault("", 1, os.args)
)

fn compare (left, right) {
	let (
		sleft  lists.atOrDefault("", columnIndex, left)
		sright lists.atOrDefault("", columnIndex, right)
		nleft  values.stringToNumberOrKeep(sleft)
		nright values.stringToNumberOrKeep(sright)
	)

	match [nleft, nright] {
	case [number, number]:
		sort.compare(nleft, nright)
	default:
		sort.compare(sleft, sright)
	}
}

os.stdin
-> csvparser.parse
-> function.ifNotError(sort.do(compare))
-> function.ifNotError(csvtemplate.println)
-> log.ifError