pattern-identification-data-extraction-format-string

pattern-identification-data-extraction-format-string

[Emanuel Berg]

Check this out:

    (car
     (last
      (message-tokenize-header "From: Joe Hacker <get@this.data>"
                               "<>") )) ; => get@this.data

Is there a more general way to do that, something
along the lines of:

    (pattern-identification-data-extraction-format-string
       "From: Joe Hacker <get@this.data>"
       ".*<%1>"
       "This is the data I want: %1" )

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underground experts united

Re: pattern-identification-data-extraction-format-string

[Emanuel Berg]

Emanuel Berg <embe8573@student.uu.se> writes:

> Check this out:
>
>     (car (last (message-tokenize-header "From: Joe
> Hacker <get@this.data>" "<>") )) ; => get@this.data
>
> Is there a more general way to do that, something
> along the lines of:
>
>     (pattern-identification-data-extraction-format-string
> "From: Joe Hacker <get@this.data>" ".*<%1>" "This is
> the data I want: %1" )

I was directed to [1], section "Extracting submatches
from a regex match", so I put together

    (let ((header "From: Joe Hacker <get@this.data>"))
      (save-match-data
        (string-match "<\\(.*\\)>" header)
        (match-string 1 header) )) ; => "get@this.data"

Maybe my original solution to that particular problem
is just as good, but I asked for a generic way and
this seems to be it.

[1] http://www.emacswiki.org/emacs/ElispCookbook

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Re: pattern-identification-data-extraction-format-string

[Emanuel Berg]

Emanuel Berg <embe8573@student.uu.se> writes:

> ... section "Extracting submatches from a regex
> match", so I put together ...
>
> Maybe my original solution to that particular
> problem is just as good, but I asked for a generic
> way and this seems to be it.

Even cooler:

    (defun make-match-list (num string)
      (let ((match (match-string num string)))
        (if match (cons match (make-match-list (1+ num) string) ))))

    (defun match-data-format (data match format-str)
      (save-match-data
        (string-match match data)
        (eval `(message format-str ,@(make-match-list 1 data) ))))

    (match-data-format
     "From: Joe Hacker <get@this.data>"
     "\\(.*\\): *\\(.*[[:alnum:]]\\) *<\\(.*\\)>"
     "header is: %s\nname is: %s\ne-mail is: %s") ; eval me

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Re: pattern-identification-data-extraction-format-string

[Philipp Stephani]

Emanuel Berg <embe8573@student.uu.se> schrieb am Di., 24. März 2015 um
03:30 Uhr:

> Emanuel Berg <embe8573@student.uu.se> writes:
>
> > ... section "Extracting submatches from a regex
> > match", so I put together ...
> >
> > Maybe my original solution to that particular
> > problem is just as good, but I asked for a generic
> > way and this seems to be it.
>
> Even cooler:
>
>     (defun make-match-list (num string)
>       (let ((match (match-string num string)))
>         (if match (cons match (make-match-list (1+ num) string) ))))
>
>     (defun match-data-format (data match format-str)
>       (save-match-data
>         (string-match match data)
>         (eval `(message format-str ,@(make-match-list 1 data) ))))
>
>     (match-data-format
>      "From: Joe Hacker <get@this.data>"
>      "\\(.*\\): *\\(.*[[:alnum:]]\\) *<\\(.*\\)>"
>      "header is: %s\nname is: %s\ne-mail is: %s") ; eval me
>
>
Using the 's' package you could simplify this to:

(require 's)
(defun match-data-format (data match format-str)
  (apply #'message format-str (cdr (s-match match data))))

Re: pattern-identification-data-extraction-format-string

[Emanuel Berg]

Philipp Stephani <p.stephani2@gmail.com> writes:

> Using the 's' package you could simplify this to:
>
> (require 's) (defun match-data-format (data match
> format-str) (apply #'message format-str (cdr
> (s-match match data))))

I never heard of the 's' package but this
functionality should in some form be included as
a default function! Apart from being useful it is
great PR for Elisp. It would be the first thing I'd
show a C programmer, for example.

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Re: pattern-identification-data-extraction-format-string

[Emanuel Berg]

Philipp Stephani <p.stephani2@gmail.com> writes:

> Using the 's' package you could simplify this to:
>
> (require 's) (defun match-data-format (data match
> format-str) (apply #'message format-str (cdr (s-match
> match data))))

's' is in MELPA as

    s is an available package.

         Status: Available from melpa -- [Install]
        Archive: melpa
        Version: 20140910.334
        Summary: The long lost Emacs string manipulation library.
       Keywords: [strings] 

    The long lost Emacs string manipulation library.

So "simplify" I don't know. But it looks
interesting nonetheless.

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