@gravity-ui/websql-autocomplete

WebSQL autocomplete

A tool that provides autocompletion for various sql dialects.

Autocomplete theory

In order to parse any language, you need a lexer (tokenizer) and a parser (ast builder)

Resources to research:

• The ANTLR Mega Tutorial: https://tomassetti.me/antlr-mega-tutorial/
• Code Completion with ANTLR4-c3: https://tomassetti.me/code-completion-with-antlr4-c3/

How everything works

• ANTLR4 grammar and lexer for different {dialect} are defined in src/autocomplete/databases/{dialect}/grammar directories.
• Actual parsers and lexers for different {dialect} are generated into src/autocomplete/databases/{dialect}/generated directories.
• Dialect specific code, which is required for the core logic to work, is put in src/autocomplete/databases/{dialect}/{dialect}-autocomplete.ts files.
• The core logic is inside src/autocomplete/shared/autocomplete.ts file. It uses dialect specific helpers to generate autocomplete suggestions based on current cursor position.

How to add a new dialect

• Add new dialect files to src/autocomplete/databases/{$dialect}
• Add new dialect to the typesVersions, exports variables in package.json
• Add new dialect to the databases array in build.js

Main scripts

• npm run generate - Generate parsers and lexers (Java has to be installed on your system for this to work)
• npm run test - Run tests