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• Axel Gehlert

RAG Pattern replacer

Whats can i use the pattern replacer for?

• Extract any kind of information out of input files
• Filter input files
• Convert ASCII file formats
• Quickly develop your own DSL (Domain-Specific-Language)
• Write code generators
• ...

How does it work?

In order to use rag pr, you need to write a pattern replacer script that

1) Defines the syntax of the input file (the "patterns")
2) Defines the actions to be taken depending in the input

The pattern-replacer-language is a simple OOP-Language that allows you to

• Define your own syntax rules and/ or regexps
• Do simple pattern-replacement operations based on "default replacements" and user-defined replacement on syntax-rule-level
• Define classes and methods if you need more than just syntax rules and replacements
• Use syntax rules like classes
• Use everything as an object

Is it like awk?

Yes and no.

Like awk, rag pr

• applies patterns/ regexps to an input file and performs the actions defined in the script whenever a pattern is recognized.

Unlike awk, rag pr

• needs a complete syntax description for the input file as a the "patterns".
• first reads the input file completely into "objects" and then the actions or replacements are performed like methods on those objects.
• has an oop scripting language

If you like, you can think of rag pr as a modernized version of awk.

Well, in fact first i had the idea to the pattern replacer and while working on it i found that it slightly reminded me of AWK - which is one of my favourite command line tools.