Re: [FR] :noweb-wrap header arg

[Ihor Radchenko <yantar92@posteo.net>]

Amy Grinn <grinn.amy@gmail.com> writes:

> First of all, I would like to change (defalias) the function name
> org-babel-noweb-wrap to org-babel-noweb-make-regexp. I think this in
> more in line with other functions which create regular expressions.

+1
You may even use obsolete alias (add it to lisp/org-compat.el)

> Second, the command org-babel-tangle-clean is not able to determine
> which noweb syntax is being used in any tangled source file because the
> header arguments are not tangled along with the source code.
>
> My proposal is to add an additional warning to this command, stating:
>
> """
> Warning, this command removes any lines containing constructs which
> resemble Org file links or noweb references.  It also cannot determine
> which noweb syntax is being used for any given source file, if
> :noweb-wrap was specified in the original Org file.
> """

Makes sense.
Ideally, this function should try to follow the link and lookup code
block headers, but it is already short of doing this. Improving
`org-babel-tangle-clean' is out of scope of your patch.

> +(defun org-babel-get-noweb-wrap (&optional info)
> +  "Retrieve a description the :noweb-wrap header arg from INFO.
> +
> +The description will be in the form of a list of two of strings
> +for the start and end of a reference.  INFO can be the result of
> +`org-babel-get-src-block-info' otherwise this function will parse
> +info at point."
> +  (unless info
> +    (setq info (org-babel-get-src-block-info 'no-eval)))
> +  (when-let ((raw (cdr (assq :noweb-wrap (nth 2 info)))))
> +    (let (result)
> +      (with-temp-buffer

Please, avoid creating throwaway buffers and work with strings instead.
Creating buffers (even temporary buffers) may be costly for some users
who heavily customized buffer hooks.

> +        (insert raw)
> +        (goto-char (point-min))
> +        (while (< (point) (point-max))
> +          (unless (looking-at " *\"\\([^\"]+\\)\" *")
> +            (looking-at " *\\([^ ]+\\)"))

May you please explain the rationale behind this regexp? AFAIU, it
implies that you want to allow whitespace characters inside :noweb-wrap
boundaries. But I do not think that we need to complicate things so much.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>