On 18/02/2018 18:56, Mark Carter wrote:
New scheme user here.
Suppose I'm writing a spreadsheet. The user inputs a formula for a cell.
The plan is to use guile's peg parser to convert the formula into a
lambda expression, which I then compile in order to speed-up subsequent
processing.
So, suppose I convert the user's formula to a list, which turns out to
be, for example: '(lambda (x) (+ x 13)) and compile it and save it in a
formula table:
(hash-set! my-cell-formulae some-cell-ref (compile '(lambda (x) (+ x 13))))
So I can I expect a speed-up by having done the compile, as opposed to
an eval?
I assume the answer is "yes", but I wanted to check.
We can try this out:
scheme@(guile-user)> (use-modules (system base compile))
scheme@(guile-user)> (define exp '(lambda (n)
(let loop ([i n] [total 0])
(if (= i 0)
total
(loop (1- i) (+ i total))))))
scheme@(guile-user)> (define f1 (eval exp (interaction-environment)))
scheme@(guile-user)> (define f2 (compile exp #:env
(interaction-environment)))
scheme@(guile-user)> ,time (f1 1000000)
$2 = 500000500000
;; 0.845240s real time, 0.895351s run time. 0.071494s spent in GC.
scheme@(guile-user)> ,time (f2 1000000)
$3 = 500000500000
;; 0.067317s real time, 0.067278s run time. 0.000000s spent in GC.
So the answer does seem to be "yes": the compiled procedure is much faster.
--
Vítor De Araújo
https://elmord.org/
