#  Copyright (c) 1997-2018
#  Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
#  http://www.polymake.org
#
#  This program is free software; you can redistribute it and/or modify it
#  under the terms of the GNU General Public License as published by the
#  Free Software Foundation; either version 2, or (at your option) any
#  later version: http://www.gnu.org/licenses/gpl.txt.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#-------------------------------------------------------------------------------

# @topic category functions/Formatting
# Functions for pretty printing, labels or [[latex|latex output]] of polymake types.

# @category Formatting
# Prepares a matrix for printing, prepends each row with a label and a colon.
# @param Matrix data  to be printed
# @param Array<String>  row_labels labels for the rows
# @param Array<String> elem_labels  optional labels for elements;
#  if //data// is an [[IncidenceMatrix]], [[Array<Set>]], or similar, each element will be replaced by its label.
# @return Array<String> each string ending with end-of-line
# @example
# > print rows_labeled(polytope::cube(2)->VERTICES,['a','b','c','d']);
# | a:1 -1 -1
# | b:1 1 -1
# | c:1 -1 1
# | d:1 1 1

user_function rows_labeled($;$$) {
   my ($data, $row_labels, $elem_labels)=@_;
   if (defined $row_labels) {
      is_array($row_labels) or croak( "row_labels must be an array" );
   }
   if (defined $elem_labels) {
      is_array($elem_labels) or croak( "elem_labels must be an array" );
   }
   my $i=-1;
   map {
      ++$i;
      (defined($row_labels) ? $row_labels->[$i] : $i) . ":" . join(" ", defined($elem_labels) ? @$elem_labels[@$_] : @$_) . "\n"
   } @$data;
}

# @category Formatting
# Like above, but specialized for Graphs (defined for convenience: a PTL Graph is not a container)
# @param Graph graph to be printed
# @param Array<String> elem_labels labels for the elements
# @return Array<String> each string ending with end-of-line
# @example
# > print rows_labeled(graph::cycle_graph(4)->ADJACENCY, ['a','b','c','d']);
# | a:b d
# | b:a c
# | c:b d
# | d:a c

user_function rows_labeled(Graph;$) {
   my ($graph, $labels)=@_;
   rows_labeled(adjacency_matrix($graph), $labels, $labels);
}

# @category Formatting
# Equivalent to [[rows_labeled]] with omitted //row_labels// argument.
# Formerly called "numbered".
# @param Matrix data to be printed
# @return Array<String> each string ending with end-of-line
# @example
# > print rows_numbered(polytope::cube(2)->VERTICES);
# | 0:1 -1 -1
# | 1:1 1 -1
# | 2:1 -1 1
# | 3:1 1 1

user_function rows_numbered {
   &rows_labeled;
}

# @category Formatting
# LaTeX output of a matrix.
# @param Matrix data to be printed
# @param Array<String> elem_labels  optional labels for elements;
#  if //data// is an [[IncidenceMatrix]], [[Array<Set>]], or similar, each element will be replaced by its label.
# @return String to be used with \usepackage{amsmath}

user_function latex($;$) {
   my ($data, $elem_labels)=@_;
   if (defined $elem_labels) {
      is_array($elem_labels) or croak( "elem_labels must be an array" );
   }
   # The matrix environment is more convenient than array as it is not necessary to know the number of
   # columns in advance.  Also works with rows of varying lengths.
   my $latex_string="\\begin{matrix}\n";
   my $first_line=1;
   foreach (@$data) {
     $latex_string .= "\\\\\n" unless $first_line;
     $latex_string .= join(" & ", defined($elem_labels) ? @$elem_labels[@$_] : @$_);
     $first_line=0;
   }
   $latex_string .= "\n\\end{matrix}\n";
   return $latex_string;
}

# @category Formatting
# Prepares a vector for printing, prepends each element with a label and a colon.
# @param Vector data  to be printed
# @param Array<String> elem_labels  optional labels for elements;
#  if //data// is a [[Set]], or similar, each element will be replaced by its label.
# @return String
# @example
# > $v = new Vector(0,1,2);
# > print labeled($v,["zeroth","first","second"]);
# | zeroth:0 first:1 second:2

user_function labeled($;$) {
   my ($data, $elem_labels)=@_;
   if (defined $elem_labels) {
      is_array($elem_labels) or croak( "elem_labels must be an array" );
   }
   my $i=-1;
   my @result=map {
      ++$i;
      (defined($elem_labels) ? $elem_labels->[$i] : $i) . ":" . $_
   } @$data;
   return join (" ", @result);
}

# @category Formatting
# Equivalent to [[labeled]] with omitted //elem_labels// argument.
# @param Vector data to be printed
# @return String
# @example
# > $data = new Vector(23,42,666);
# > print numbered($data);
# | 0:23 1:42 2:666

user_function numbered {
   &labeled;
}


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