sudoku-crystal/src/parser.cr

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963 B
Crystal

module Sudoku
class ParseException < Exception
end
class Parser
# Parse a sudoku board from a string. Return a board.
# The string must contain valid board rows. Each row must be separated by a newline.
# Blanks are represented by dots.
# E.g.:
# .1.2
# 2..4
# .3..
# ....
def self.parse(board_str, block_size)
rows = board_str.split('\n')
board_size = rows.size
board = Sudoku::Board.new(board_size, block_size)
rows.each_with_index { |row, y|
if row.size != board_size
raise ParseException.new("Invalid row size: #{row.size} for row: #{row}")
end
row.each_char_with_index { |c, x|
case c
when '.'
board.put(nil, x, y)
when .number?
board.put(c.to_s.to_i, x, y)
else
raise ParseException.new("Invalid character: #{c}")
end
}
}
board
end
end
end