Hi Sahithi, do you have any questions about the next steps outlined in the email below?
Cheers, Ricardo Ricardo Wurmus <rek...@elephly.net> writes: > Hi Sahithi, > >>> Have you started on working on this yet? If so,could you please give us >>> an update on your progress via email? >>> >> I have started out using different functions like >> >> |1) regexp-match 2) ||string-contains which resulted same output for >> strings > > The procedures tell you if something matched. > >> then i tried 1) >> string-match 2) string-substitute ended up using string substitute so >> that the result can be colored one. > > “string-match” either returns #f if the expression didn’t match or it > returns a match structure that tells you *how* the expression was > matched. It is especially useful with match groups that are marked with > parentheses in the regular expression. See below for an example. > >> But I failed executing it. File is >> attached, Can u suggest where I went wrong. > > One obvious failing is in the arguments to “make-soft-port”. It takes a > vector of five procedures, but you gave it a vector of one procedure > followed by an expression beginning with “regexp-substitute/global” and > then three more procedures. > > You need to give it five procedures wrapped in a vector. > > How about doing it this way: > > --8<---------------cut here---------------start------------->8--- > ;; The port to which we write our potentially colorized strings > (define target-port (current-output-port)) > > (define (handle-string str) > "Match on the input string STR and return a new string with added > color sequences." > ;; TODO: match on str and pass the modified string to the output port > (display str target-port)) > > (define my-colorful-port > (make-soft-port > (vector > (lambda (c) (write c target-port)) > handle-string > (lambda () (display "." target-port)) > (lambda () (char-upcase (read-char))) > (lambda () (display "@" target-port))) > "rw")) > > ;;;; Some tests! > > (display "Hello there!" my-colorful-port) ; no colours > (display "starting phase “Big gorilla” — watch out!" my-colorful-port) > (display "phase “Big gorilla” failed" my-colorful-port) > (display "I heard phase “Big gorilla” failed" my-colorful-port) ; no colours > here > ;;; …and so on… > --8<---------------cut here---------------end--------------->8--- > > Now all you need to do is work on the “handle-string” procedure. > > I suggest using simpler matching procedures at first. To get started > try “string-prefix?” and use it with the string “starting phase”. This > won’t work with regular expressions, though. > > While you *can* use “regexp-substitute/global”, I don’t think it’s a > good fit here, because we may want to extend the string matching > features, which is difficult to do with “regexp-substitute/global”. > Instead, try to match regular expressions one by one with “string-match” > and then operate on the match structure it returns. If it returns #f > you can move on to the next expression. If none match you just return > the original string. If one matches you *rebuild* the string, but with > colours applied. > > Here’s an example: > > (define str "My name is Al Jarreau and I’m 76 years old.") > (define expr "(My name is )(.*)( and I’m )(.*)( years old.)") > > These are five match groups and we want to modify the second and fourth, > so we can do this: > > (or (and=> (string-match expr str) > (lambda (m) > (string-append > (match:substring m 1) > (string-upcase (match:substring m 2)) > (match:substring m 3) > (string-reverse (match:substring m 4)) > (match:substring m 5)))) > ;; Didn’t match, so return unmodified string. > str) > > If you don’t understand this example please look up the procedures in > the Guile manual. > >> As per IRC discussion with Ricardo, I tried installing emacs and >> running a shell. > > That is correct. We were trying to take a look at the features > guix-build-log-minor-mode provides, but we didn’t get that far. -- Ricardo
