I have modified the PLSQL parser given by [Porcelli] (https://github.com/porcelli/plsql-parser). I am using this parser to parse PlSql files. After successful parsing, I am printing the AST. Now, I want to edit the AST and print back the original plsql source with edited information. How can I achieve this? How can I get back source file from AST with comments, newline and whitespace. Also, formatting should also be remain as original file. Any lead towards this would be helpful.
Each node in an AST comes with an index member which gives you the token position in the input stream (token stream actually). When you examine the indexes in your AST you will see that not all indexes appear there (there are holes in the occuring indexes). These are the positions that have been filtered out (usually the whitespaces and comments).
Your input stream however is able to give you a token at a given index and, important, to give you every found token, regardless of the channel it is in. So, your strategy could be to iterate over the tokens from your token stream and print them out as they come along. Additionally, you can inspect your AST for the current index and see if instead a different output must be generated or additional output must be appended.