We took help from Code Mirror, i.e Code Mirror gives the parsed SQL from the editor through a tree called syntaxTree and by using some logic we extracted the statements which have semicolon in it and also added some extra logic to break the whole query on next of next line as empty or if comments are there.
Using all this logic we got the individual queries and checked where our cursor is in editor and checked with the query and through this we got the actual query at cursor position.
For example,
if the cursor is at starting or ending position or anywhere in between a query with semicolon or without semicolon, that can be single line or multi line then the query gets extracted.
if the cursor is at starting or ending position or anywhere in between a comment that can be single line or multi line then the comment gets extracted.
if the cursor is at a position where the previous line has a query then that query gets extracted.
For the anonymous block containing multiple queries, code mirror gives the statements differently. That is an incomplete query we can say, so the query tool gives error. We can say some limitations are there with Code Mirror.
Please let me know if you have any questions on this.
My main concern is that it doesn't get it wrong. Ever. Consider:
DELETE FROM foo; SELECT * FROM foo;
Is that one statement or two? What if it's in the middle of a pl/python3 function:
my_sql = 'DELETE FROM foo; SELECT * FROM foo;'
or
my_sql = """DELETE FROM foo;
SELECT * FROM foo;
"""
Or, indeed, an SQL function. Would the user want the CREATE statement to be run, or just the embedded SQL statement? I wouldn't like to guess.