December 2011 - alexandria-devel - mailman3.common-lisp.net

[alexandria-devel] Question about FORMAT-SYMBOL
by Luís Oliveira 26 Jan '13

26 Jan '13

Hello, I often try to support Allegro's modern mode by doing things like (format-symbol t "~A-~A" :foo :bar). We just came across an issue on #quicklisp where a user had set his *PRINT-CASE* to :DOWNCASE and that caused FORMAT-SYMBOL to intern lower-case symbols, thus breaking the idiom I described. Should fix my code to use SYMBOLICATE instead or should FORMAT-SYMBOL use WITH-STANDARD-IO-SYNTAX? Any opinions? -- Luís Oliveira http://r42.eu/~luis

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[alexandria-devel] generic mean, variance, median, standard-deviation
by Tamas Papp 21 Jan '12

21 Jan '12

Hi, Would it be possible to make MEAN, VARIANCE, MEDIAN, and STANDARD-DEVIATION generic? The concepts are meaningful for objects other than sequences --- including arrays and random-variables (see cl-random), sequences pre-sorted for easy quantile calculation, etc. Currently I am shadowing these and redefining them as generic in some of my libraries. I am happy to implement the change and send a patch. Best, Tamas

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[alexandria-devel] [PATCH] lazy-evaluate the default value in ENSURE-GETHASH
by Ryan Davis 20 Jan '12

20 Jan '12

I'm using a hash-table as a cache, and had a problem with ensure-gethash. Some example code / output: CL-USER> (let ((h (make-hash-table))) (alexandria:ensure-gethash :x h (progn (format T "expensive computation~%") 1)) (alexandria:ensure-gethash :x h (progn (format T "expensive computation~%") 1))) expensive computation expensive computation 1 T CL-USER> This patch (created using git format-patch origin/master) converts ENSURE-GETHASH to a macro that only evaluates the default if we get to the setf branch. Has a check to create and call a lambda if the default value looks complicated (using CONSTANTP). After applying my patch, here's the output: CL-USER> (let ((h (make-hash-table))) (alexandria:ensure-gethash :x h (progn (format T "expensive computation~%") 1)) (alexandria:ensure-gethash :x h (progn (format T "expensive computation~%") 1))) expensive computation 1 T CL-USER> Thoughts? Thanks, -- Ryan Davis Acceleration.net Director of Programming Services 2831 NW 41st street, suite B Gainesville, FL 32606 Office: 352-335-6500 x 124 Fax: 352-335-6506

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