awk: emulate 'pr -mt file*'

Question

While I was playing with awk's multi file processing construct

awk 'NR == FNR { # some actions; next} # other condition {# other actions}' file*.txt

I asked myself, if it's possible to convert text files with different sizes for printing with awk like with

pr -mt file*

Assuming:

file1.txt

arbitrary text of the first file,
which is not so long.

More arbitrary text of the first file.

file2.txt:

Arbitrary text of the second file.
More arbitrary text of the second file.
More and More arbitrary text of the second file.
It's going on.
But finally every text will end.

The output sould be like this:

$ pr -w150 -mt file*
arbitrary text of the first file,         Arbitrary text of the second file.            
which is not so long.                     More arbitrary text of the second file.       
                                          More and More arbitrary text of the second file.  
More arbitrary text of the first file.    It's going on.                    
                                          But finally every text will end.  

How to achieve this with awk command only with having on file*.txt?

Answer 1

You could record all the lines of every file, noting the maximum line length and number of lines for each and then print all the lines in the end:

awk '
  FNR == 1 {f++}
  {line[f, FNR] = $0}
  length > width[f] {width[f] = length}
  FNR > max_lines {max_lines = FNR}
  END{
    for (row = 1; row <= max_lines; row++) {
      for (i = 1; i <= f; i++)
        printf "%-*s", (i == f ? 0 : width[i] + 2), line[i, row]
      print ""
    }
  }' ./*.txt