search.craigslist <- function(site.url = "http://atlanta.craigslist.org",
                              ncol     = 3L) {

## This function prompts the user with questions for searching Craigslist
## (search items, price, etc.) and displays the search results into an image
## gallery.
##
## Inputs:
##    - site.url: Craigslist site URL
##    - ncol:     the number of columns for the output image gallery
##
## Output: none. As a side effect, a browser is opened.

   query      <- readline("search Craigslist for: ")
   category   <- .pick.category()
   title.only <- readline("search titles only (press 1 or ENTER to skip): ")
   min.price  <- readline("min price (press ENTER to skip): ")
   max.price  <- readline("max price (press ENTER to skip): ")
   pic.only   <- readline("pic only  (press 1 or ENTER to skip): ")

   title.only <- title.only == "1"
   min.price  <- as.integer(min.price)
   max.price  <- as.integer(max.price)
   pic.only   <- pic.only == "1"

   url <- search.url(query      = query,
                     site.url   = site.url,
                     category   = category,
                     title.only = title.only,
                     min.price  = min.price,
                     max.price  = max.price,
                     pic.only   = pic.only)

   image.gallery(url, ncol = ncol)
}