Script to convert file containing shogi SFENs to commands for LaTeX rendering

sfen_to_latex.py

# === SFEN-to-LaTeX-tsumeshogi-converter ===
# Just a quick and dirty conversion of SFEN notation from a file into LaTeX
# commands for rendering using the myshogi.sty package.
# Specifically, assumes the SFEN from the "Sfen" copy option of ShogiGUI.

# Example of SFEN line:
# position sfen 3sks3/9/4S4/9/1B7/9/+p+l+n+sg+b+r1K/9/9 b r3g3n3l17p 1 moves 

# Example of desired output (tsume mode):
#
# \begin{minipage}[t]{0.45\linewidth}
# \begin{myshogi}
# \banmen
# \mochigoma{\sente}{0}{0}{0}{1}{0}{0}{0}
# \koma{51}{\gote}{\gyoku}
# \koma{41}{\gote}{\gin}
# \koma{61}{\gote}{\gin}
# \koma{53}{\sente}{\tokin}
# \koma{85}{\sente}{\uma}
# \end{myshogi}
# \end{minipage}

import argparse
import re

PATTERN_FEN_SYMBOL = re.compile(r"\d|\+\w|\w")
PATTERN_DROPS = re.compile(r"\d*[a-zA-Z]") # need to account for >9 pawns

# FEN symbol to LaTeX commands
SYMBOL_TO_LATEX_COMMAND = {
    "P": "\\fu", "+P": "\\tokin",
    "p": "\\fu", "+p": "\\tokin",
    "L": "\\kyou", "+L": "\\narikyou",
    "l": "\\kyou", "+l": "\\narikyou",
    "N": "\\kei", "+N": "\\narikei",
    "n": "\\kei", "+n": "\\narikei",
    "S": "\\gin", "+S": "\\narigin",
    "s": "\\gin", "+s": "\\narigin",
    "G": "\\kin",
    "g": "\\kin",
    "B": "\\kaku", "+B": "\\uma",
    "b": "\\kaku", "+b": "\\uma",
    "R": "\\hi", "+R": "\\ryu",
    "r": "\\hi", "+r": "\\ryu",
    "K": "\\gyoku",
    "k": "\\ou"
}

# FEN piece symbol to drop array indices
SYMBOL_TO_DROP_IDX = {
    "R": 0, "B": 1, "G": 2, "S": 3, "N": 4, "L": 5, "P": 6,
    "r": 0, "b": 1, "g": 2, "s": 3, "n": 4, "l": 5, "p": 6
}

def parse_sfen_board(fen, out):
    ranks = fen.split("/")
    row = 1
    for rank in ranks:
        col = 9
        symbols = PATTERN_FEN_SYMBOL.findall(rank)
        for symbol in symbols:
            if symbol.isdigit():
                col -= int(symbol)
            else:
                piece_side = "\\sente" if symbol.isupper() else "\\gote"
                piece_type = SYMBOL_TO_LATEX_COMMAND[symbol]
                out.append("\\koma{%d%d}{%s}{%s}\n" %
                    (col, row, piece_side, piece_type)
                )
                col -= 1
        row += 1
    return out

def parse_sfen_mochigoma(drops, out, is_tsume=False):
    drop_array = [[0] * 7, [0] * 7] # sente then gote, pieces in order RBGSNLP
    drop_list = PATTERN_DROPS.findall(drops)
    for drop in drop_list:
        drop_symbol = "".join(filter(str.isalpha, drop))
        digits = "".join(filter(str.isdigit, drop))
        drop_number = 1 if digits == "" else int(digits)
        is_gote = drop_symbol.islower()
        
        drop_array[int(is_gote)][SYMBOL_TO_DROP_IDX[drop_symbol]] = drop_number
        
    out.append("\\mochigoma{%s}{%d}{%d}{%d}{%d}{%d}{%d}{%d}\n" %
        tuple(["\\sente"] + drop_array[0])
    )
    if not is_tsume:
        out.append("\\mochigoma{%s}{%d}{%d}{%d}{%d}{%d}{%d}{%d}\n" %
            tuple(["\\gote"] + drop_array[1])
        )
    return out


# "main" function

# parsing command line arguments
parser = argparse.ArgumentParser(description="Generate .txt file containing LaTeX commands (from myshogi.sty) to render input file containing shogi FENs.")
parser.add_argument("input_file", type=str, help="Input text file containing one SFEN per line.")
parser.add_argument("output_file", type=str, nargs="?", default="shogi_latex.txt", help="Output text file. Will be created if it does not exist.")
parser.add_argument("-t", "--tsume", action="store_true", help="Use this flag to specify that the file contains tsumeshogi problem, suppressing gote's pocket.")
args = parser.parse_args()

# open files and read/write
with open(args.input_file, "r") as sepd_file:
    with open(args.output_file, "w") as out_file:
        for line_num, line in enumerate(sepd_file):
            sfen = line.split(" ")
            sfen_board = sfen[1]
            sfen_pockets = sfen[3]
            
            # actual writing to file
            out_file.write("\\begin{minipage}[t]{0.45\\linewidth}\n"
                           "\\begin{myshogi}\n"
                           "\\banmen\n")
            out_file.write("".join(parse_sfen_mochigoma(sfen_pockets, [], args.tsume)))
            out_file.write("".join(parse_sfen_board(sfen_board, [])))
            out_file.write("\\end{myshogi}\n"
                           "\\end{minipage}\n")
            # assumes LaTeX will display 2 diagrams per row on a page
            if line_num % 2 == 1:
                out_file.write("\n")