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newlinem4

How to match newlines in GNU M4 _properly_

I am trying to craft a macro replacing newlines.

My first try was:

    define(`m4_pascal_str',`
     patsubst(`$1',`^\(.*\)$',`\1++')
')

m4_pascal_str(`

11

22 33 44
')

define(zz,`

11

22 33 44
')
m4_pascal_str(`zz')

That gives correct answer when not using intermediate macro, and match only last newline otherwise. See results below:

 ++

++
11++
++
22 33 44++

++

11

22 33 44
++

Then I found similar question: in m4's patsubst, how do I replace newlines with spaces?

So, I just made:

define(`m4_pascal_str',`
     patsubst(`$1',`
',`++')
')

m4_pascal_str(`

11

22 33 44
')

define(zz,`

11

22 33 44
')
m4_pascal_str(`zz')

It gives:

 ++++11++++22 33 44++

11

22 33 44

The last alternative suffers the same problem. Any suggestions?

Solution

  • For the last line try removing the quoting around the zz. When I did this I got the same result for both m4_pascal_str calls:

         ++
++
11++
++
22 33 44++
++




     ++
++
11++
++
22 33 44++
++