Hog/QL tasklist

[mariusandra]

Consolidated todos for the Hog language. There's another list to track the HogQL todos, and this does not directly touch upon the CDP project. This list is a work in progress.

Hog todo

• Hog in template string
• Objects, arrays, tuples and nested assignment
• Support for JSON parsing and stringifying
• Add bytecode to state for serialization
• Run the same set of tests for both python and typescript VMs
• Debugger
• Bit of AST/VM work
  • Global objects fail
  • Can we get rid of semicolons
  • Return does not work without a value but gets interpreted as a field/string (fixed in the same PR)
  • for loops
  • Add more comment types?
  • How to call Log/Print/Echo print
• Placeholders should not parse inside Hog
• Trailing commas
• C++ parser
• Make editing Hog not suck v1 (errors, syntax highlighting)
• Make editing Hog not suck v2 (autocomplete for template strings and expressions)
• Make editing Hog not suck v3 (autocomplete in Hog, bring in inputs and other globals)
• Ternary operators (? :) don't work (translated to if(...)
• Nullish coalescing (?.) support
• Swap to RE2 for regex in HogVMs - make regexes safe for user input (see codeql)
• Add resource monitoring and limits to ensure things like unbounded Arrays don't exhaust resources (see codeql)
• Ensure function access is definitely safe (see codeql)
• for-in loops / iterators
• Date functions
• Hash functions for Kinesis
• Report undefined globals (easy to make typos)
• Make a decision on string quotes and dict keys (it's fine with better editor support)
• Make a decision on array indexes starting with 0 vs 1 https://github.com/PostHog/product-internal/pull/623
• Exceptions
• Ways to bring down used memory?
• Implement lambdas and closures
• Change fn to fun
• Run Hog natively in the browser
• Run Hog in multi-part notebooks (tech demo)
• typeof for Avo plugin
• Spec out the STL and then add all the functions
• Keep using maps in TS?
• Assure object equality is done by value everywhere
• Get HogQL/SQL nodes into the bytecode to run(select *) natively
• Add map* fields, work well with hogqlX as well.
• Optimize Hog's stack and internal objects (e.g. callables) to use less space
• Deprecate ?. ?
• Move function in front of args in bytecode for CALL_LOCAL
• Quit early (no 2nd hop after webhooks if not needed)
• Types for variables and function arguments / return
• Prettier for Hog/QL
• re2 in the Python HogVM (we're not using it live today)
• Remove DECLARE_FN
• Replace crypto with webcrypto (& polyfill on the nodejs side)

HogQL todos

• HogQL & Data Exploration next steps #81
• HogQL Insights #130