.. _ruleref: Rules Reference =============== `Rules` in `SQLFluff` are implemented as `crawlers`. These are entities which work their way through the parsed structure of a query to evaluate a particular rule or set of rules. The intent is that the definition of each specific rule should be really streamlined and only contain the logic for the rule itself, with all the other mechanics abstracted away. Specific Rules -------------- .. automodule:: sqlfluff.core.rules :members: :member-order: alphabetical Implementation -------------- .. autoclass:: sqlfluff.core.rules.base.RuleSet :members: .. autoclass:: sqlfluff.core.rules.base.BaseRule :members: :private-members: .. autoclass:: sqlfluff.core.rules.base.LintResult :members: .. autoclass:: sqlfluff.core.rules.base.LintFix :members: The `_eval` function of each rule should take enough arguments that it can evaluate the position of the given segment in relation to its neighbors, and that the segment which finally "triggers" the error, should be the one that would be corrected OR if the rule relates to something that is missing, then it should flag on the segment FOLLOWING, the place that the desired element is missing. Inline Ignoring Errors ----------------------- `SQLFluff` features inline error ignoring. For example, the following will ignore the lack of whitespace surrounding the ``*`` operator. .. code-block:: sql a.a*a.b AS bad_1 -- noqa: L006 Multiple rules can be ignored by placing them in a comma-delimited list. .. code-block:: sql a.a * a.b AS bad_2, -- noqa: L007, L006 It is also possible to ignore non-rule based errors, and instead opt to ignore templating (``TMP``) & parsing (``PRS``) errors. .. code-block:: sql WHERE dt >= DATE_ADD(CURRENT_DATE(), INTERVAL -2 DAY) -- noqa: PRS Should the need arise, not specifying specific rules to ignore will ignore all rules on the given line. .. code-block:: sql a.a*a.b AS bad_3 -- noqa Ignoring line ranges ^^^^^^^^^^^^^^^^^^^^ Similar to `pylint's "pylint" directive"`_, ranges of lines can be ignored by adding :code:`-- noqa:disable=[,...] | all` to the line. Following this directive, specified rules (or all rules, if "all" was specified) will be ignored until a corresponding `-- noqa:enable=[,...] | all` directive. .. code-block:: sql -- Ignore rule L012 from this line forward SELECT col_a a FROM foo --noqa: disable=L012 -- Ignore all rules from this line forward SELECT col_a a FROM foo --noqa: disable=all -- Enforce all rules from this line forward SELECT col_a a FROM foo --noqa: enable=all .. _`pylint's "pylint" directive"`: http://pylint.pycqa.org/en/latest/user_guide/message-control.html