Copybook

Copybook is a python module for parsing VSAM copybooks.

Features

• Supports all numeric PIC variations including:
  • integers
  • floats described with dot notation
  • floats described with V notation
  • leading SIGNED
  • trailing SIGNED
• Character PIC notations
• Groups
• OCCURS clauses
• REDEFINES clauses

In addition, it provides indexes of column locations to help with parsing fixed width files based on positions within each line

Installation

pip install copybook

Usage

Copybook provides two methods for parsing copybooks: parse_file and parse_string. The result is a FieldGroup object that represents the root of the copybook tree.

Examples:

import copybook
text = """
       01  WORK-BOOK.
        10  TAX-RATE        PIC S9(13)V9(2)
                    SIGN LEADING SEPARATE.
"""
root = copybook.parse_string(text)

Using Copybook module to parse a fixed width line

The FieldGroup object provides a flatten method that return a flat list of Field objects.

Example:

import copybook
text = """
       01  WORK-BOOK.
        10  TAX-RATE        PIC S9(13)V9(2)
                    SIGN LEADING SEPARATE.
        10  AMOUNT        PIC S9(4)V9(2).
"""
# copybook also provides a parse_file method that receives a text filename
root = copybook.parse_string(text)

# flatten returns a list of Fields and FieldGroups instead of traversing the tree
list_of_fields = root.flatten()

# dummy sample input
line = "          -13452987654"

# loop over the fields and parse the relevant position in the line
for field in list_of_fields:

  # FieldGroups are Copybook groups and contain Field objects as children
  if type(field)==copybook.Field:

    # each Field has a start_pos and a get_total_length method
    # to identify the position within the raw line input
    str_field = line[field.start_pos:field.start_pos+field.get_total_length()]

    # Field provides a parse method that returns a str, int, or float based on the PIC
    print(f"{field.name}: {field.parse(str_field)}")

Development

PRs are always welcome!

Support

If you encounter an unsupported copybook feature, please paste the copybook example along with whatever logs or error message you have received and open an issue.

Gratitude

Copybook uses the awesome PyParsing library for tokenization

License

MIT