[ES|QL] Regexp literal AST node improvements

[ ] Remove underscored _ in not_like and not_rlike nodes.
- [ ] Or, even better add not: true/false flag to regexp nodes.

When IN or regex LIKE or RLIKE operators are prefixed by NOT modifier, we should keep the original operator name and add the "not" flag to the AST node, instead for changing the operator name.

Currently LIKE and NOT LIKE operators produce two different operator names:

{type: 'function', name: 'like'} // column LIKE "abc"
{type: 'function', name: 'not_like'} // column NOT LIKE "abc"

Instead we could use the same operator name but attach a not flag:

{type: 'function', name: 'like'} // column LIKE "abc"
{type: 'function', name: 'like', not: true} // column NOT LIKE "abc"

This way, when pretty printing ES|QL query from AST, we could just print the name property:

return `${node.not ? 'NOT ' : ''}${node.name}`

Now we have to loop through all possible cases:

switch (node.name) {
  case 'like': return 'LIKE';
  case 'not_like': return 'NOT LIKE';
  case 'rlike': return 'RLIKE';
  case 'not_rlike': return 'NOT RLIKE';
}

The same holds for the IN and NOT IN binary operators.

elastic / kibana

[ES|QL] Regexp literal AST node improvements #190359