On 18/02/2018 18:56, Mark Carter wrote:

New scheme user here.## Advertising

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 alambda expression, which I then compile in order to speed-up subsequentprocessing.So, suppose I convert the user's formula to a list, which turns out tobe, for example: '(lambda (x) (+ x 13)) and compile it and save it in aformula 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 toan 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/