Re: sed and perl - yuck [Was Re: Preprocessor functionality equivalent ideas needed]

[hebisch@math.uni.wroc.pl (Waldek Hebisch)]

Martin Krischik (krischik@users.sourceforge.net) wrote:
: Ludovic Brenta wrote:

: > Another approach could be to simulate a preprocessor with sed or perl
: > scripts.

: Did that, hated it and wrote AdaCL. If you rather use Ada then perl and find
: find sed cumbersome you should look at AdaCL.

: If you disagree: Write a sed line which inserst "OS." bevore every
: CD_Recorder -  but only if it is not allready there.

Well, if you have unused chars (say ';' and '#') the task is easy:

s/CD_Recorder/;CD_Recorder/g
s/OS\.;/OS.#/
s/;CD_Recorder/OS.CD_Recorder/g
s/[;#]//g

If all chars are used one have to quote first:

s/./:&/g
s/:C:D:_:R:e:c:o:r:d:e:r/;::C:D:_:R:e:c:o:r:d:e:r/g
s/:O:S:\.;:/:O:S:.;#/g
s/;::C:D:_:R:e:c:o:r:d:e:r/:O:S:.:C:D:_:R:e:c:o:r:d:e:r/g
s/;#:/:/g
s/.\(.\)/\1/g

I have not put them on sigle line for readability. The above is 
slightly off-topic, but I think it ilustrates nicely that a sequence
of simple steps can give result looking quite different then a single
step. In that spirit Ada discourages preprocessors (since complexity
grows quite a lot).

--
                              Waldek Hebisch
hebisch@math.uni.wroc.pl