Low-wage, part-time jobs in retail can be among the most maddening jobs. You don't control your hours, or how many of them you get, or when you're expected to work them. You may come in for an eight-hour shift and be sent home after four — with only a half-day's income. You may be told, on a moment's notice, that you're working Thanksgiving after all. And all of this means that it's hard to plan the rest of your time, including time you may need for a second job.

Unpredictability is a big part of retail work, undermining the ability of workers to plan night school, or child care. But now one city has adopted a law trying to rein it in. On Tuesday, city supervisors in — surprise! — San Francisco adopted two pieces of legislation, sponsored by different backers, that together make up the "Retail Workers Bill of Rights." A quick summary from the San Francisco Business Times:

[Eric] Mar's ordinance requires businesses to pay employees for four hours if an employee is either on-call or sent home early, and mandates businesses to offer extra hours to part-time workers before hiring new employees. [David] Chiu's legislation calls on formula retail stores to post employees' schedules 14 days in advance, give workers extra pay for changing a schedule at the last minute, and allow the same access to requests for time off and particular work schedules to part-time workers that they do for full-time employees.

The group behind the bill, Jobs With Justice, is planning to lobby for similar protections elsewhere.

In San Francisco, the new policies won't help anyone in time for Black Friday. They'll go into effect in six months. They also apply only to retail stores, restaurants and hotel chains with more than 11 locations. That will cover about 12 percent of the retail establishments in the city, and about half of all retail workers there.

As Mother Jones points out, the bill targets a practice that's been very good for employers but bad for workers:

This is partly a symptom of retailers' increasing reliance on computerized "on call" scheduling systems that track weather predictions and real-time sales data to schedule work shifts—maximizing efficiency but wreaking havoc on workers' ability to manage their personal schedules.

Indeed, San Francisco's Chamber of Commerce has warned that the bill will hamstring retailers from reacting to changes in the market. The National Employment Law Project, on the other hand, says it's a model framework for how to create better jobs in an economy that's now producing a whole lot of low-wage and part-time service-sector work.