Nimrod: A new approach to meta programmingΒΆ
| Authors: | Andreas Rumpf |
|---|---|
| Time: | 13:00 |
| Session: | https://thestrangeloop.com/sessions/nimrod-a-new-approach-to-meta-programming |
| Link: | http://nimrod-code.org/ |
| Slides: |
Agenda: Overview of Nimrod and some implementation aspects, followed by Hello World and then moving into metaprogramming.
Nimrod is a statically typed systems programming language. It has a clean syntax and strong meta-programming capability (for example, you can declare the not equals operator for Nimrod in Nimrod). Nimrod compiles to C, C++, and Objective-C. Portions of it also compile to Javascript.
Nimrod provides a realtime GC with exhibits maximum pause times of 1-2 milliseconds. The compiles provides dead code elimination, and the stdlib is designed to leverage this: for example, if you’re using parsing, it doesn’t use regular expressions, so the regular expression portion is optimized away. (The GC can also be optimized away!)
Example:
echo "hello ", "world", 99
is rewritten to:
echo([$"hello ", $"world", $99])
echo is declared as a procedure (function), and $ (the toString operator) is applied to every argument. This type conversion is local: only in this context are the arguments converted [not sure what else could happen?].
Nimrod’s focus is meta programming via macros. For example:
template htmlTag(Tag:expr) {.immediate.} =
proc tag(): string = "<" & astToStr(tag) & ">"
htmlTag(br)
htmlTag(html)
echo br()
echo html()
Produces:
<br>
<html>
Note that calls to htmlTag use the parameter name to create a procedure of the same name.
[Shows additional examples]
Macros can also be used to implement DSLs. [shows example of an HTML templating DSL; looks pretty slick] Macros support rewriting as well as simple expansion.
[Additional in depth metaprogramming examples.]
[Shows examples of % and optFormat]
Those look a lot alike, what about reducing duplication using templates? Yup, Nimrod does that.