Indented multi-line strings (was: "Data blocks" syntax specification draft)

[Peter J. Holzer]

On 2018-05-22 23:25:36 +0000, Dan Strohl via Python-list wrote:
> > So, e.g. this:
> > 
> > data = /// s4
> >     first line
> >     last line
> > the rest python code
> > 
> > - will parse the block and knock out leading 4 spaces.
> > i.e. if the first line has 5 leading spaces then 1 space will be left in the string.
> > Block parsing terminates when the next line does not satisfy the indent
> > sequence (4 spaces in this case).
> > Another obvious type: tabs:
> 
> OK, I CAN see this as a potentially useful suggestion.  There are a
> number of times where I would like to define a large chunk of text,
> but using tqs and having it suddenly move to the left is painful
> visually.  Right now, I tend to either a) do it anyway, b) do it in a
> separate module and import the variables, or c) do it and parse the
> string to remove the extra spaces.

Agreed.


> Personally though, I would not hard code it to knock out 4 leading
> spaces.   I would have it handle spaces the same was that the existing
> parser does, if there are 4 spaces indending the next line, then it
> removes 4 spaces, if there are 6 spaces, it removes 6 spaces, etc...
> ignoring additional spaces within the data-string object.  Once it
> hits a line that has the same number if indenting spaces as the
> initial token, the data-string object is finished.

How about this?

    x = ''''
        Here is a multi-line string
            with
          indentation.
        ''''

This would be equivalent to 

    x = 'Here is a multi-line string\n    with\n  indentation.'

Rules:

 * The leading and trailing '''' must be aligned vertically.
 * The contents of the string must be indented at least as far as the
   delimiters (and with consistent tabs/spaces).
   This leading white space is ignored.
 * All the leading white space beyond this 'left edge' is preserved.
 * The newlines after the leading '''' and before the trailing '''' are
   ignored, all the others preserved. (I thought about preserving the
   trailing newline, but it is easier to add one than remove one.)

        hp


-- 
   _  | Peter J. Holzer    | we build much bigger, better disasters now
|_|_) |                    | because we have much more sophisticated
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__/   | http://www.hjp.at/ | -- Ross Anderson <https://www.edge.org/>
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