boxit

#!/usr/bin/env bash
# boxit: Format text inside box-drawing sections.
# Reads from stdin, waits for EOF (^D), then prints output to stdout.
# Lines containing three dashes will be converted into separators!

# Usage: boxit [--round]

# Copyright 2019 Ethan McTague
# License to use, modify, and distribute this software is granted to
# any and all entities wherever permitted by law.

output=`cat`
maxwidth=`echo "$output" | wc -L`
corners="┌,┐,└,┘"

if [ "$1" == "--round" ]; then
  corners="╭,╮,╰,╯"
fi

read -r -d '' awkscript <<'EOF'
function lines(a, b) { printf a; for(c=0; c < maxwidth+2; c++) { printf "─"; } printf "%s\n", b; }
BEGIN { split(corners, co, ","); lines(co[1], co[2]); }
{
  if ($0=="---") lines("├", "┤");
  else printf "│ %-*s │\n", maxwidth, $0
}
END { lines(co[3], co[4]); }
EOF

echo "$output" | awk -v maxwidth="$maxwidth" -v corners="$corners" "$awkscript"