问题
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?
回答1:
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++
++
来源：https://stackoverflow.com/questions/3078827/how-to-match-newlines-in-gnu-m4-properly