File : aligncols.bush

$ bush aligncols
$ cat columned.txt 
Given      a          text       file   of     many      lines,     where    fields  within  a      line  
are        delineated by         a      single 'dollar'  character, write    a       program 
that       aligns     each       column of     fields    by         ensuring that    words   in     each  
column     are        separated  by     at     least     one        space.   
Further,   allow      for        each   word   in        a          column   to      be      either left  
justified, right      justified, or     center justified within     its      column. 

   Given        a        text     file    of      many     lines,     where   fields  within    a   line  
    are    delineated     by        a   single  'dollar' character,   write     a    program 
   that      aligns      each    column   of     fields      by     ensuring   that   words    in   each  
  column       are     separated   by     at     least       one     space.  
 Further,     allow       for     each   word      in         a      column     to      be   either left  
justified,    right   justified,   or   center justified   within      its   column. 

      Given          a       text   file     of      many     lines,    where  fields  within      a line 
        are delineated         by      a single  'dollar' character,    write       a program
       that     aligns       each column     of    fields         by ensuring    that   words     in each 
     column        are  separated     by     at     least        one   space.
   Further,      allow        for   each   word        in          a   column      to      be either left 
 justified,      right justified,     or center justified     within      its column.

#!/usr/local/bin/bush

-- A common interview test from Rosetta Code for testing basic programming
-- skills.

pragma annotate( "aligncols" );
pragma annotate( "" );
pragma annotate( "Given a text file of many lines, where fields within a line are delineated ");
pragma annotate( "by a single 'dollar' character, write a program that aligns each column of" );
pragma annotate( "fields by ensuring that words in each column are separated by at least one" );
pragma annotate( "space. Further, allow for each word in a column to be either left justified," );
pragma annotate( "right justified, or center justified within its column. " );
pragma annotate( "A modified version of the Ada solution from Rosetta Code" );
pragma annotate( "translated by Ken O. Burtch" );

procedure aligncols is
   Text : constant string :=
      "Given$a$text$file$of$many$lines,$where$fields$within$a$line$" & ASCII.NUL &
      "are$delineated$by$a$single$'dollar'$character,$write$a$program" & ASCII.NUL &
      "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$" & ASCII.NUL &
      "column$are$separated$by$at$least$one$space." & ASCII.NUL &
      "Further,$allow$for$each$word$in$a$column$to$be$either$left$" & ASCII.NUL &
      "justified,$right$justified,$or$center$justified$within$its$column." & ASCII.NUL;
   File : file_type;
   Width : array(1..1000) of natural;
   ch : character;
   Column : positive := 1;
   Start : positive := 1;
   type Alignment is ( Left, Center, Right );
   str : string;
   padding : natural;
begin
   -- Zero Widths
   for I in arrays.first( Width )..arrays.last( Width ) loop
       Width(I) := 0;
   end loop;
   -- Determining the widths of columns
   for I in 1..strings.length(Text) loop
      ch := strings.element( Text, I );
      case ch is
         when '$' | ASCII.NUL =>
            Width (Column) := numerics.max(Width (Column), I - Start + 1);
            Start  := I + 1;
            if strings.element( Text, I ) = ASCII.NUL then
               Column := 1;
            else
               Column := @+1;
            end if;
         when others =>
            null;
      end case;
   end loop;
   create( File, out_file, "columned.txt" );
   -- Formatting
   for Align in Left..Right loop
       Column := 1;
       Start := 1;
       for I in 1..strings.length(Text) loop
          ch := strings.element( Text, I );
          case ch is
             when '$' | ASCII.NUL =>
                str := strings.slice( Text, Start, I-1 );
                padding := (Width( Column ) - strings.length(str));
                case Align is
                when Left =>
                  str := @ & (padding * ' ');
                when Center =>
                  declare
                     -- business shell 1: must trunc specifically
                     left_padding : natural := numerics.truncation( padding/2 );
                     right_padding : natural := padding - left_padding;
                  begin
                     str := (left_padding * ' ') & @ & (right_padding * ' ');
                  end;
                when Right =>
                  str := (padding * ' ') & @;
                when others =>
                    null;
                end case;
                put( File, str );
                Start := I+1;
                if ch = ASCII.NUL then
                   new_line( File );
                   Column := 1;
                else
                   Column := @+1;
                end if;
             when others =>
                null;
          end case;
       end loop;
       new_line( File );
   end loop;
   close( File );
end aligncols;