Concatenative Programming

Hey, it includes Factor!

• Discussion on reddit
• Manual

This is not my own project!

Discussion on HackerNews

Slint is a GUI toolkit, and is largely not relevant to concatenative programming. But the latest release adds a touch of postfix to the mix, which is nice to see.

From the blog post:

Math Gains Postfix Support

A subtle but profound change to the language. Traditional syntax:

Math.max(20, Math.abs(value.x))

New postfix syntax:

value.x.abs().max(20)

The new syntax improves readability by making the transformation steps more explicit. It works well for many operations but has limitations:

Effective for simple transformations (e.g., abs, max) Less intuitive for operations like clamp or atan2.

pos.y.atan2(pos.x) // Less clear than atan2(pos.y, pos.x)

So for now you cannot use postfix for all functions in the Math namespace. We may revisit these cases later, so give them a try and let us know your thoughts.

Discussion on lobsters

Explanation: https://gist.github.com/Dobiasd/bb9d38a027cf3164e66996dd9e955481

I am not the author.

PDF: https://storage.googleapis.com/gweb-research2023-media/pubtools/1004848.pdf

I wanted to map over a nested array in factor so I created a helper function:

: nested-map ( a quote -- a' ) swap [ over map ] map nip ;

which i then called with

{ { 1 2 } { 3 4 } } [ 1 + ] nested-map

But when I call it I get the error from the title.

If I just paste the body of the function it works as intended:

{ { 1 2 } { 3 4 } } [ 1 + ] swap [ over map ] map nip

So I guess I have two questions: is there a better way to achieve the original goal, but also how am I supposed to create higher order functions without getting this error?