numbering across files

Author: RaihanSharif

implement-shell-tools/cat/cat.py

@@ -28,31 +28,29 @@ def read_file(path):
 
 # -b (number the non-empty lines) takes priority over -n (number all lines)
 # if both are present
-def format_lines(lines, number_all=False, number_nonempty=False):
+def format_lines(lines, line_num, number_all=False, number_nonempty=False):
     """Returns a list of formatted output lines"""
     output = []
-    
     if number_nonempty:
-        line_num = 0
         for line in lines:
             if line == "":
                 output.append("")
             else:
-                line_num += 1
                 # {line_num:6} right justied number, length of at least 6
                 # {some_str:6} left justifed string, length fo at least 6
                 output.append(f"{line_num:6}\t{line}")
+                line_num += 1
     elif number_all:
-        for i, line in enumerate(lines, start=1):
-            output.append(f"{i:6}\t{line}")
+        for _, line in enumerate(lines, start=1):
+            output.append(f"{line_num:6}\t{line}")
+            line_num += 1
     else:
         output = lines
 
     return output
 
 
-# TODO: runner function to call read_file, and feed it into formatLines, then print
-def cat_file(path, number_all=False, number_nonempty=False):
+def cat_file(path, line_num, number_all=False, number_nonempty=False):
     """
     Calls read_file -> format_lines -> prints formatted line. 
     Returns True if file read successfully, else returns False
@@ -62,27 +60,29 @@ def cat_file(path, number_all=False, number_nonempty=False):
     content, error = read_file(path)
     if (error):
         print(error, file=sys.stderr)
-        return False
+        return -1
 
     # splitlines automatically trims trailing empty lines
     lines = content.splitlines()
-    for line in format_lines(lines, number_all, number_nonempty):
+    for line in format_lines(lines, line_num, number_all, number_nonempty):
         print(line)
 
-    return True
+    return len(lines) + line_num
 
 
 def main():
     # cat exits with error code 1 if any file read fails
     file_error = False
 
-    for path in args.paths:
-        line_num = 1
-        is_success = cat_file(path, args.n, args.b)
-
-        if not is_success:
+    line_num = 1
+    for path in args.paths:    
+        result = cat_file(path, line_num, args.n, args.b)
+        if result < 0:
             file_error = True
 
+        if result > 0:
+            line_num = result
+
     # if at any point, file reading failed file error is set to True, 
     # and program exist with code 1 after all tasks completed
     sys.exit(1 if file_error else 0)