nikaaboda/parser

Generic parser for flat files

Generic Flat File Parser

Currently Supported Functionalities

• Transforming StratEDI Orders/Invoices/Deasdvs into XML and back.
• Validating StratEDI files content.

Usage

This parser provides 2 main classes Reader and Writer.

Reader

Reader class transforms StratEDI file in XML. Its main function is read.

Calling read function:

Reader.read() function takes 3 arguments:

Argument	Type	Description
format	“STRATEDI”	Format of file that parser should canonicalize. (currently only supports “STRATEDI”)
fileType	“ORDER” “INVOICE” “DEASDV”	Type of file of the specified format that parser should canonicalize.
file	string	Content of file that parser should canonicalize.

read function return value:

read function returns object with two fields file and errors.

Field	Description
file (string)	xml that’s been produced from provided StratEDI file. (double quotes replaced with single).
errors (array of objects)	Error messages that’s been produced by validator describing inconsistencies between the provided StratEDI file and the StratEDI guidelines.

Writer

Writer class transforms XML file in StratEDI. Its main function is write.

Writer.write() function takes 3 arguments:

Argument	Type	Description
format	“STRATEDI”	Format of file that parser should decanonicalize xml into. (currently only supports “STRATEDI”)
fileType	“ORDER” “INVOICE” “DEASDV”	Type of file of the specified format that parser should decanonicalize xml into.
file	string	Content of file that parser should decanonicalize xml into.

Writer.write() function returns decanonicalized string.

Implementation

Besides Reader and Writer there are 3 main classes that cover implementation: Parser, Tokenizer, and Validator.

Class	Description
Parser	Parser repeatedly calls Tokenizer to get the next token and depending on the value of token decompose the given file into sentences and words. Its main method is parse(). This method is the entry point of the class: it starts the decomposition of the given file and when the whole is parsed, it returns an abstract syntax tree(AST).
Tokenizer	Tokenizer's main method is getNextToken(). This method gets the next word according to specification of provided file format which is stored in constants, validates it with the help of Validator and returns it to Parser. This class keeps track of where is the file cursor, tokenIndex, sentenceType and so on. This is the most important class for parsing.
Validator	Validator is called by Tokenizer . It checks if the provided token satisfies the specifications provided of the given file format, and if that’s not so, it returns an object with the message that describe inconsistency between the given file and guidelines of that file format.