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Alphabetical linting ..

3 November 2022 22:00

So this week I recycled a talk I'd given in the past, about how even using extremely simple parsers allows a lot of useful static-analysis to be done, for specific niche use-cases.

This included examples of scanning comments above classes to ensure they referred to the appropriate object, ensuring that specific function calls always included a specific (optional) parameter, etc.

Nothing too complex, but I figured I'd give a new example this time, and I remembered I'd recently written a bunch of functions for an interpreter which I'd ordered quite deliberately.

Assume you're writing a BASIC interpreter, you need to implement a bunch of built-in maths functions such as SIN, COS, TAN, then some string-related functions LEFT$, RIGHT$, MID$, etc.

When it comes to ordering there are a couple of approaches:

  • Stick them all in one package:
    • builtins/builtins.go
  • Create a package and group them:
    • builtins/maths.go
    • builtins/string.go
    • .. etc

Personal preference probably dictates the choice you make, but either way I think it would be rational and obvious that you'd put the functions in alphabetical order:

func ABS( args []primitive.Object) (primitive.Object, error) {

func COS( args []primitive.Object) (primitive.Object, error) {

func SIN( args []primitive.Object) (primitive.Object, error) {

func TAN( args []primitive.Object) (primitive.Object, error) {

I did that myself, and I wrote a perl-script to just parse the file using a simple regexp "^func\s+([^(]+)\(" but then I figured this was a good time to write a real static-analysis tool.

The golang environment is full of trivial little linters for various purposes, and the standard "go vet .." driver makes it easy to invoke them. Realizing that I was going to get driven in the same way it was obvious I'd write something called "alphaVet".

So anyway, half written for a talk, half-written because of the name:

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