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Developer Documentation
This page contains information about how to extend this parser with new functionalities.
Implementing Statement Class
Create a new file and class in src/lib/statements/ or extend any of the existing Statements. Every statement needs to have the base class SQLStatement and needs to call its super constructor with its type. If your defining a new statement type, you need to define a new StatementType in SQLStatement.h.
It is important that you create an appropriate constructor for your statement that zero-initializes all its pointer variables and that your create an appropriate destructor.
Lastly you need to include your new file in src/lib/sqllib.h
Extending the Grammar
Related files:
- src/parser/bison_parser.y
- src/parser/flex_lexer.l
- src/parser/keywordlist_generator.py
- src/parser/sql_keywords.txt
To extend the grammar the file you will mostly have to deal with is the bison grammar definition in src/parser/bison_parser.y.
If your extending an existing statement, skip to the non-terminal definition for that statement. I.e. for an InsertStatement the non-terminal insert_statement.
If your defining a new statement, you will need to define your type in the %union directive hsql::ExampleStatement example_stmt. Next you need to associate this type with a non-terminal \%type <example_stmt> example_statement. Then you have to define the non-terminal example_statement. Look the other non-terminals for statements to figure out how.
Implementing Tests
Related files:
- src/sql_tests.cpp