{"id":10859,"date":"2020-11-12T00:48:34","date_gmt":"2020-11-11T23:48:34","guid":{"rendered":"https:\/\/www.salvis.com\/blog\/?p=10859"},"modified":"2023-11-12T13:59:39","modified_gmt":"2023-11-12T12:59:39","slug":"formatter-callback-functions","status":"publish","type":"post","link":"https:\/\/www.salvis.com\/blog\/2020\/11\/12\/formatter-callback-functions\/","title":{"rendered":"Formatter Callback Functions"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

In this blog post<\/a>, I explained how the formatter in SQL Developer works and outlined how you can change the formatter result using Arbori and JavaScript. In this post, I explain what exactly the provided formatter callback functions do. For that, I use simple examples. I produced all results with a patched version of SQL Developer 20.2. However, I expect that the results for versions 20.2, 19.4 and 19.2 will be the same.<\/p>\n\n\n\n

Minimal Arbori Program<\/h2>\n\n\n\n

Before looking at the callback function, I’d like to reduce the Arbori program to the minimum. Why? Because this visualises the default behaviour of the formatter. Furthermore, it will simplify the subsequent examples.<\/p>\n\n\n\n

One could think about removing the entire Arbori program. But that won’t work. An empty Arbori program is an invalid Arbori program and SQL Developer will reset it to the default.<\/p>\n\n\n\n

A minimal Arbori program looks as follows, the comment section explains the required parts.<\/p>\n\n\n\n

Minimal Arbori Formatter Program<\/span><\/path><\/path><\/svg><\/span>
\/**<\/span><\/span>\n * Minimal version of a custom Arbori formatter program.<\/span><\/span>\n *<\/span><\/span>\n * oracle.dbtools.app.Format checks if <\/span><\/span>\n *<\/span><\/span>\n *    - skipWhiteSpaceBeforeNode exists<\/span><\/span>\n *    - :indentConditions is used somewhere<\/span><\/span>\n *<\/span><\/span>\n * The Arbori program is considered invalid, if these <\/span><\/span>\n * minimal requirement are not met and it is reset <\/span><\/span>\n * to the default value.<\/span><\/span>\n *\/<\/span><\/span>\n<\/span>\ndummy<\/span>:  <\/span><\/span>\n  :<\/span>indentConditions<\/span> & [<\/span>node<\/span>) <\/span>'dummy_node_cond'<\/span> <\/span><\/span>\n;<\/span><\/span>\n<\/span>\nskipWhiteSpaceBeforeNode<\/span>:<\/span><\/span>\n  [<\/span>node<\/span>) <\/span>'dummy_node_skip_ws_before'<\/span>  <\/span><\/span>\n  -><\/span><\/span>\n;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
I use default values for all other formatter settings as the following three screenshots show.<\/p>\n\n\n