From 62f8fc3b5696fe45c146fecf5f8d0f816616f839 Mon Sep 17 00:00:00 2001
From: Jan Wille <mail@janwille.de>
Date: Tue, 12 Jul 2022 16:46:25 +0200
Subject: [PATCH] more comments

---
 csv2xlsx.py | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/csv2xlsx.py b/csv2xlsx.py
index d4e03c9..45610aa 100644
--- a/csv2xlsx.py
+++ b/csv2xlsx.py
@@ -33,35 +33,49 @@ def main(glob_pattern, outdir, separator):
 
     spinner = cycle(["-", "/", "|", "\\"])  # a spinner to dislay "work in progress"
 
+    # loop over all files matching the glob pattern
     for csvfile in glob(glob_pattern):
+
+        # handle output dir:
         outdir = path.join(path.dirname(csvfile), outdir)
         makedirs(outdir, exist_ok=True)  # ensure outdir exists
+
+        # create workbook object:
         xlsxfile = path.join(outdir, path.basename(csvfile)[:-4] + ".xlsx")
         workbook = Workbook(xlsxfile)
         worksheet = workbook.add_worksheet()
-        r, c = 0, -1
-        with open(csvfile, "rt", encoding="utf8") as fp:
+
+        r = 0
+        c = -1  # we start at c=-1 because the first action is to increment c to 0
+        with open(csvfile, "r") as fp:
 
             for line in fp.readlines():
+                # remove newline characters from the end of the line:
                 line = line.strip("\n")
+
+                # loop over all the elements in a line:
                 for token in line.split(separator):
-                    c += 1
-                    token = token.strip(" \t")
+                    c += 1  # first thing we do is increment so we can skip empty tokens
+                    token = token.strip(" \t")  # remove uneeded whitespace
                     if not token:
-                        continue
+                        continue  # skip empty tokens
+
+                    # escaped "string" tokens are written as is:
                     if token.startswith('"'):
                         token = token.strip('"')
                         worksheet.write(r, c, token)
+
+                    # all not-strings are assumed to be numbers:
                     else:
                         if token == "nan":
-                            continue
+                            continue  # skip nan's
                         try:
                             worksheet.write_number(r, c, float(token))
                         except ValueError:  # Non-numbers that are not escaped with "
                             worksheet.write(r, c, token)
-                c = -1
                 r += 1
-                print("\r" + next(spinner), end="")
+                c = -1
+                print("\r" + next(spinner), end="")  # display "work in progress"
         try:
             workbook.close()
             print(f"\rconverted: {csvfile} -> {xlsxfile}")