CODEWITHSUNDEEP
antlrantlr4
user1480864
user1480864

Reputation: 1585

ANTLR: Source to Target Language Conversion

I have fair understanding on ANTLR & grammar. Is it correct to say ANTLR can do source language to target language conversion like ASP to JSP or COBOL to JSP? if yes, could you help me to provide some information/tutorial/link to explorer the possibilities?

Idea is to pragmatically translating huge amounts of code from source to target using ANTLR.

Thanks

Upvotes: 2

Views: 2386

Answers (1)

GRosenberg
GRosenberg

Reputation: 6001

The basic steps to building a translator in Antlr4 is to:

  1. generate a parse tree from an input text in the source language
  2. repeatedly walk the parse tree to analyze the nodes of the parse tree, adding and evolving properties (decorator pattern) associated with individual parse tree nodes -- the properties will describe the change(s) required to represent the content of the node in the target language.
  3. final walk of the parse tree to collect and output the target language text.

The form and content of the properties and the progression of creation and evolution will be entirely dependent on the nature of the source and target languages and the architect's conversion strategy.

Since Antlr parse-tree walks can be logically independent of one another, specific conversion aspects can be addressed in separate walks. For example, one walk can evaluate (possibly among other things) whether individual perform until statements will be converted to if or while statements. Another walk can be dedicated to analyzing variable names to ensure they are created/accessed in the correct scope and determining the naming and scope of any target language required temporary variables. Etc.

Given that the conversion is a one-time affair, there is no fundamental penalty to implementing 5, 10, or even more walks. Just the 'whatever makes sense in your case' practicality.

The (relevant) caveat addressed in the other QA is how to handle conversions where there is no simple or near identity between statements in the two languages. To convert a unique source language statement then requires a target language run-time package be created to implement the corresponding function.

GenPackage (I am the author) automates the generation of a basic conversion project. The generated project represents but one possible architectural approach and leaves substantial work to be done to tailor it to any particular end use.

Upvotes: 6

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