Include (Python) listener

[svengiegerich]

Motivation: I'd like to use our grammar's (Python) listener to facilitate the parser's utility beyond SQL execution.
More concretely, I'm currently playing around with extracting a dependency tree for my SQL-based pipeline based on the listener.
👉 I propose to ship the listener within the package

Changes: Removed arg no-listener for Python target & re-generated grammar

[ivergara]

@svengiegerich just a small suggestion, keep the changes in the generating code from the changes in the generated code in different commits. In this case is not critical, but when there are multiple manual changes, particularly big ones, it's hard to distinguish from the autogenerated code.

[svengiegerich]

@svengiegerich just a small suggestion, keep the changes in the generating code from the changes in the generated code in different commits. In this case is not critical, but when there are multiple manual changes, particularly big ones, it's hard to distinguish from the autogenerated code.

Thanks! You're right, I was lazy this time 🙈

[svengiegerich]

(In light of PR #73, I'll need to update this PR before the review can continue)

[SimeonStoykovQC]

Could consider adding a test that asserts one of the "listener" callbacks is called when parsing a simple SQL statement.

[svengiegerich]

Thanks, @SimeonStoykovQC.

Could consider adding a test that asserts one of the "listener" callbacks is called when parsing a simple SQL statement.

I do like the idea! But how would I do this? Do I need to mock the class TSqlParserListener?

[SimeonStoykovQC]

Do I need to mock the class TSqlParserListener?

You can try, yes. Do you have an idea how you will use it -- from what I see it's just method stubs with pass? Can you provide your implementation of the listener interface upon parsing?

[svengiegerich]

Do you have an idea how you will use it -- from what I see it's just method stubs with pass?
Can you provide your implementation of the listener interface upon parsing?

In the end - outside of the package - I'd like to do smth like this:

class DependencyFinder(TSqlParserListener.ParseTreeListener):
    def __init__(self):
        self.table = ""
        self.visit_source = 0
        self.table_dependencies = []

    def enterTable_sources(self, ctx):
        self.visit_source+=1
        
    def exitTable_sources(self, ctx):
        self.visit_source-=1

    def enterFull_table_name(self, ctx):
        if self.visit_source > 0:
            self.table_dependencies.append(ctx.getText())
        else:
            self.table = ctx.getText()

    def enterTable_name(self, ctx):
        if self.visit_source > 0:
            self.table_dependencies.extend(ctx.getText())
        else:
            self.table = ctx.getText()

    def enterSimple_name(self, ctx):
        self.table = ctx.getText()

    def print_results(self):
        print(f"Table: {self.table}")
        print(f"Dependencies: {self.table_dependencies}")

tree = parse(InputStream(data=sql), "tsql_file")
walker = antlr4.ParseTreeWalker()
dependency_finder = DependencyFinder()
walker.walk(dependency_finder, tree)
dependency_finder.print_results()

[svengiegerich]

Merging now; I'll add the test separately.