Pure functions (mobile code, contexts)

I think providing a distinction between ordinary and pure functions has benefits and adds a little to certainty. Besides being sure that a branch of calls is referentially transparent I also nurture this idea of mobile code. And the first candidate for mobile code are pure functions, as you can run pure remote code with much less worry since there are no side effects. There is still a halting problem, but can be solve on interpreter level I think.

Imagine communicating with a map-filter-reduce server also written in Rye and instead of translating requests into it's query language you can just sent it your pure functions for map/filter/reduce and get the result.

The implementation is quite simple. All pure builtins have a Pure flag set and pure user functions can only call pure builtins or other pure functions.

I didn't like the idea, that interpreter would need to always check the flags of all builtins and functions when evaluating the pure function. I figured out a way that solves this with separate contexts (scopes).

Rye is very flexible with scopes (in rye called contexts). Scope is a first class value in Rye. You can for example create isolated context, use current context and/or combine and link contexts together as you see fit. Functions and blocks of code can then be ran in these constructed contexts, not just lexical/dynamic scopes like in most programming languages.

So we solve this simply by having an isolated context, where all pure functions and builtins get are defined also. And pure functions evaluate their code using this scope only.

This is a simple demonstration.

Next blogpost will be about what we can also do in with our definitional scopes, inspired by reading this well written blogpost.

Komentarji

Priljubljene objave iz tega spletnega dnevnika

Ryelang - controlled file serving example and comparison to Python

This is as anecdotal as it gets, but basic HTTP serving functions in Rye seem to be working quite OK. They do directly use the extremely solid Go 's HTTP functions, so that should be somewhat expected. I made a ryelang.org web-server with few lines of Rye code 3 months ago and the process was running ever since and served more than 30.000 pages. If not else, it seems there are no inherent memory leaks in Rye interpreter. Those would probably show up in a 3 month long running process? And now I got another simple project. I needed to make a HTTP API for some mobile app. API should accept a key, and return / download a binary file in response if the key is correct. Otherwise it should return a HTTP error. So I strapped in and created Rye code below. I think I only needed to add generic methods stat and size? , all other were already implemented, which is a good sign. Of course, we are in an age of ChatGPT, so I used it to generate the equivalent Python code. It used the ele...

Preberite več

Receiving emails with Go's smtpd and Rye

This goes a while back. At some project for user support, we needed to receive emails and save them to appropriate databases. The best option back in the day seemed project Lamson . And it worked well ever since. It was written in Python by then quite known programmer Zed Shaw. It worked like a Python based SMTP server, that called your handlers when emails arrived. It was sort of Ruby on Rails for email. We were using this ever since. Now our system needs to be improved, there are still some emails or attachments that don't get parsed correctly. That isn't the problem of Lamson, but of our code that parses the emails. But Lamson development has been passive for more than 10 years. And I am already moving smaller utilities to Rye. Rye uses Go, and Go has this nice library smtpd , which seems like made for this task. I integrated it and parsemail into Rye and tested it in the Rye console first. Interesting function here is enter-console , that can put you into Rye console any...

Preberite več

Go's concurrency in a dynamic language Rye

The Rye programming language is a dynamic scripting language based on REBOL’s ideas, taking inspiration from the Factor language and Unix shell. Rye is written in Go and inherits Go’s concurrency capabilities, including goroutines and channels. Recently, Rye gained support for Go’s select and waitgroups. Building blocks Goroutines Goroutines are lightweight threads of execution that are managed by the Go/Rye runtime. They operate independently, allowing multiple tasks to run concurrently without blocking each other. Creating a Goroutine in Rye is straightforward. The go keyword is used to launch a new Goroutine, followed by the Rye function to be executed concurrently. For instance, the following code snippet creates and starts a Goroutine that prints a message after a delay: ; # Hello Goroutine print "Starting Goroutine" go does { ; does creates a function without arguments sleep 1000 print "Hello from Goroutine!" } print "Sleepi...

Preberite več

ryelang

Preišči ta spletni dnevnik