The embodiments provide for automatic incremental learning of programming language grammar. A corpus (i.e., a text file of software code written in a particular programming language) is parsed based on a set of grammar rules. An unparsed statement from the corpus is identified along with a section thereof, which did not match any of the grammar rules in the set. A subset of the set of grammar rules at fault for the parsing failure is identified. Groups of new grammar rules are developed such that each group comprises at least one new grammar rule, such that each group can parse the unparsed statement, and such that each new grammar rule is a modification of grammar rule(s) in the subset. One specific group can then be selected for possible incorporation into the set of grammar rules. Optionally, before a specific group is selected, the groups can be heuristically pruned and/or ranked.