string-replace question -- changing names like variable_name to variableName

string-replace question -- changing names like variable_name to variableName

[bc]

Is there an easier way to do this short of some lisp like:

(replace-string "_a" "A")
(replace-string "_A" "A")
(replace-string "_b" "B")
etc.

Thanks,
bc

Re: string-replace question -- changing names like variable_name to variableName

[John McCabe]

On Tue, 03 Sep 2002 09:17:58 -0400, bc <bc@example.net> wrote:

>
>Is there an easier way to do this short of some lisp like:
>
>(replace-string "_a" "A")
>(replace-string "_A" "A")
>(replace-string "_b" "B")

yes.

From the documentation of replace-string...

"This function is usually the wrong thing to use in a Lisp program.
What you probably want is a loop like this:
  (while (search-forward FROM-STRING nil t)
    (replace-match TO-STRING nil t))
which will run faster and will not set the mark or print anything.
(You may need a more complex loop if FROM-STRING can match the null
string
and TO-STRING is also null.)"

Are you using a lisp program? If so, you probably want to use a
regexp-search and replace.

Try this function:

(defun get-rid-of-underscore ()
  (interactive)
  (while (re-search-forward "_\\([a-zA-Z]\\)?" nil t)
    (replace-match (upcase (match-string 1)) nil nil)))


on this data:

hello_aorld
hello_Aorld
hello_borld
hello_Borld
hello_corld
hello_Corld
hello_dorld
hello_Dorld
hello_eorld
hello_Eorld


Does it work?

Re: string-replace question -- changing names like variable_name to variableName

[lawrence mitchell]

bc wrote:

[...] variable_name --> variableName
> Is there an easier way to do this short of some lisp like:
> (replace-string "_a" "A")
> (replace-string "_A" "A")
> (replace-string "_b" "B")
> etc.

Why yes there is.  Using a small amount of knowledge of regexps,
and a few other Emacs functions.

Note firstly, that the docstring of replace-string explicitly
recommends against its use in lisp programs:

/----[ C-h f replace-string RET ]
| This function is usually the wrong thing to use in a Lisp program.
| What you probably want is a loop like this:
|   (while (search-forward FROM-STRING nil t)
|     (replace-match TO-STRING nil t))
| which will run faster and will not set the mark or print anything.
\----

However, neither replace-string nor search-forward allow the use
of regexps in their syntax, hence, we need to use the regexp
equivalents, namely re-search-forward

Using these bits of information, we come up with
something like:

(let ((case-fold-search nil))           ; make sure we don't ignore
                                        ; case in our search, if this
                                        ; isn't a problem, then change
                                        ; the nil on this line to t.
  (while (re-search-forward             ; search forward for a regular
                                        ; expression.

          "\\([a-z]\\)_\\([a-z]\\)"     ; this regexp matches
                                        ; something of the form:
                                        ; foo_bar, but not _bar, or
                                        ; foo_. If you want to match
                                        ; capitalised letters add A-Z
                                        ; to the character
                                        ; groupings. Or change the
                                        ; binding of case-fold-search
                                        ; to t.

          nil                           ; no bound on the search

          t)                            ; don't error if the match is
                                        ; not found.

    (replace-match                      ; replace the matched text with:

     (concat (match-string 1)           ; a concatenation of the 1st
                                        ; \\(..\\) grouping. and...
             (upcase                    ; the uppercase equivalent of:

              (match-string 2)))        ; the 2nd \\(..\\) grouping.

     t)))                               ; since we've gone to all the
                                        ; trouble of changing the
                                        ; case, treat our string as FIXEDCASE

I hope the comments are suitably explanatory.

-- 
lawrence mitchell <wence@gmx.li>

Re: string-replace question -- changing names like variable_name to variableName

[bc]

John McCabe wrote:
> 
<snip>
> Try this function:
> 
> (defun get-rid-of-underscore ()
>   (interactive)
>   (while (re-search-forward "_\\([a-zA-Z]\\)?" nil t)
>     (replace-match (upcase (match-string 1)) nil nil)))
> 
> on this data:
> 
> hello_aorld
> hello_Aorld
> hello_borld
> hello_Borld
> hello_corld
> hello_Corld
> hello_dorld
> hello_Dorld
> hello_eorld
> hello_Eorld
> 
> Does it work?

Works great, and very educational on helping with
my lisp programming.  Thanks much!

Re: string-replace question -- changing names like variable_name to variableName

[Stefan Monnier <foo@acm.com>]

Continuing the great tradition of answering to a different question than
the one that was asked, I'll point you to glasses-mode (distributed with
Emacs-21) which doesn't change the buffer's content but allows you to
display "variableName" as "variable_name".


        Stefan

Re: string-replace question -- changing names like variable_name to variableName

[John McCabe]

On Tue, 03 Sep 2002 10:47:40 -0400, bc <bc@example.net> wrote:

>> Does it work?
>
>Works great, and very educational on helping with
>my lisp programming.  Thanks much!

You're welcome. Glad to be of assistance.