| # PerfettoSQL Style Guide |
| |
| _This page provides a suggested style guide for writing PerfettoSQL and is in |
| use inside the PerfettoSQL standard library in the trace processor. It also |
| provides guidance on the autoformatter._ |
| |
| ## Rules |
| |
| 1. Keep lines below 80 characters long |
| 2. Function names, macro names and table/view names should all be lower snake |
| case. |
| 3. SQL keywords should all be upper case |
| 4. When line-breaking SQL expressions, place the joining keyword (AND/OR) at the |
| _start of the next line_ rather than the _end of the previous line_. |
| |
| ## Autoformatter |
| |
| PerfettoSQL comes with an auto-formatter as implemented by `tools/format_sql.py` |
| Python script. This is a simple script which can be run over any set of files or |
| directories and automatically formats the code to adhere to the above rules. |
| |
| This script is _required_ to be run when making contributions to the standard |
| library. It's automatically executed as part of running `tools/gen_all` which is |
| part of the standard development workflow in Perfetto. Presubmit will check to |
| make sure you've done this. |
| |
| The autoformatter is not perfect by any means and does often have subtle edge |
| cases: |
| 1. It doesn't handle comments in the middle of complex expressions. Prefer |
| placing comments at the start of these expressions instead of in the middle. |
| 2. It doesn't format macro invocations as they have very complex semantics |
| in many cases. |
