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lib/App/Chart/Suffix/LME.pm  view on Meta::CPAN

			   (chart-symbol-mdate symbol))
		      (lat (string-append commodity ".LME")))

		  # all rows with month in symbol
		  (lat symbol))))

	  commodity-list buyer-row seller-row))
       row-list)))

  (and-let* ((m (string-match "LMEX Index value [^0-9\n]*([0-9]+ [A-Za-z]+ [0-9][0-9][0-9][0-9])[^0-9.\n]+([0-9.]+)" body)))
    (set! ret (cons (list "LMEX.LME"
			  #f
			  (d/m/y-str->tdate (match:substring m 1))
			  #f # no separate buy price
			  (match:substring m 2)
			  #f)
		    ret)))

  ret)



(define (daily-latest-parse body)
  (list
   (cons 'form   (html-form-parse body))
   (cons 'prices (daily-html-parse body))))

(define (daily-latest-info type)
  (lme-ensure-login)

  (pagebits-read #:filename  (case type
			       ((metals)   "lme-latest-metals")
			       ((plastics) "lme-latest-plastics"))
		 #:status    (list (_ "LME")
				   (case type
				     ((metals)   (_ "metals latest"))
				     ((plastics) (_ "plastics latest"))))
		 #:url       (list (case type
				     ((metals)   
				     ((plastics) "https://secure.lme.com/Data/community/Dataprices_daily_prices_plastics.aspx"))
				   #:cookiejar lme-cookiejar-filename
				   #:follow    #f)
		 #:timezone  (timezone-london)
		 #:parse     daily-latest-parse))


#-----------------------------------------------------------------------------
# latest
#
# This uses the daily prices in the login "free data service", login
# required, at
#
#     https://secure.lme.com/Data/community/Dataprices_daily_metals.aspx
#
# This plain url gives the most recent prices, which we take as a quote for
# the indicated day then work back with form-data fetching previous days to
# find price change amounts.  Or the database is used if it covers the
# desired symbol(s).
#
# Unfortunately there's no Last-Modified or ETag to save refetching if the
# latest GET contents have not yet updated.  (???)


(define (lme-latest-update-database type newest-data prev-data)
  (let* ((end-tdate   (data-tdate newest-data))
	 (start-tdate (if prev-data
			  (data-tdate prev-data)
			  end-tdate))
	 (db-list     (download-also '() #:selector (lme-type->selector type)
				     #:start-tdate start-tdate
				     #:end-tdate end-tdate)))
    (if prev-data
	(daily-process db-list prev-data))
    (daily-process db-list newest-data)))

(define (lme-latest-process newest-data prev-data proc)
  (define lst '())

  (for-each
   (lambda (elem)
     (receive-list (symbol name tdate buy sell mdate)
	 elem

       (and-let* ((prev-elem (assoc symbol prev-data))) # match car
	 (let ((prev-sell (fifth prev-elem)))

	   (receive-list (decimals buy sell prev-sell)
	       (strings->numbers+decimals buy sell prev-sell)

	     # need both buy and sell to show as quote
	     (define bid         buy)
	     (define offer       (and buy sell))
	     (define quote-tdate (and buy sell tdate))

	     # sell is normally always present, but have seen entire page
	     # blank (empty fields "" which become #f) 31aug05 after
	     # 29aug05 bank holiday

	     (set! lst
		   (cons (latest-new #:symbol         symbol
				     #:name           name
				     #:quote-tdate    quote-tdate
				     #:bid            bid
				     #:offer          offer
				     #:last-tdate     tdate
				     #:last           sell
				     #:prev           prev-sell
				     #:decimals       decimals
				     #:contract-mdate mdate
				     #:source         'lme)
			 lst)))))))
   newest-data)

  (proc lst))

(define (lme-latest-type symbol-list type proc)

  (and-let* ((newest-data  (assq-ref (daily-latest-info type) 'prices)))

    # COVERED-TDATE is the data we already have for all of SYMBOL-LIST (or
    # rather for the worst among that list), default to a dummy 100 days