semi-structured text parsing using machine learning
Without a sample of your data, it's unclear what's the structure of your data and what tool is suitable to process it.

Here are some blind recommendations based on my experience:


If you just need some flexibilty parsing the text record, such as variable repeat number of certain field, or conditional parsing of fields, then you should check out this python library: http://construct.readthedocs.org/en/latest/
it allows you to first define a hirachcal structure of your data, and then apply this structure to parse information from a text file. It's especial useful when parsing binary files.
If you're looking for an algorithm that can actually "understand" your text data and "infer" the structure in a smart way. Then you might want to try graph based approach: 
http://kavita-ganesan.com/opinosis