When comparing Nim vs ATS, the Slant community recommends Nim for most people. In the question“What are the best (productivity-enhancing, well-designed, and concise, rather than just popular or time-tested) programming languages?” Nim is ranked 4th while ATS is ranked 43rd. The most important reason people chose Nim is:
Checks your code at compile time.
Ranked in these QuestionsQuestion Ranking
Pro Strict typing
Checks your code at compile time.
Pro Really crossplatform
The same code can be used for web, server, desktop and mobile.
Pro Easy to read
Nim has a lot of common with Python in terms of syntax.
Indentation-based syntax, for/while loops
Pro Built-in Unicode support
You can use unicode names for variables, there is "unicode" module for operations with unicode
Pro Multi paradigm
Imperative, OOP, functional programming in one language.
Pro Great metaprogramming features
There are generics, templates, macros in Nim. They can allow you to write new DSL for your application, or avoid all boilerplate stuff.
Pro Type interferencing
You only need to specify types in your procedures and objects - you don't need to specify type when you're creating a new variable (unless you're creating it without initialization)
Pro Has built-in unittest module
With built-in "unittest" module you can create test with a very readable code
You don't need to deal with all those manual memory allocations, Nim can take care of it!
But also you can use another GC, or tweak it for you real-time application or a game
Pro Easy to integrate with another languages
You can use Nim with any language that can be interfaced with C.
There's a tool which helps you to create new C and C++ bindings for Nim - c2nim
Pro Compile-time execution
Nim has built-in VM, which executes macros and some other code at compile time.
For example - you can check if you're on Windows, and Nim will generate code only for it
Pro Supports UFCS (Unified Function Call Syntax)
writeLine(stdout, "hello") can be written as stdout.writeLine("hello")
proc add(a: int): int = a + 5 can be used like 6.add.echo or 6.add().echo()
Pro Has built-in async support
Nim has "asyncdispatch" module, which allows you to write async applications.
Pro Built-in formal specification
ATS has a theorem-proving type system powerful enough to prove that its functions meet their specifications. This happens at compile time with no performance impact at runtime. This can be used to prove that an ATS program doesn't have bugs commonly found in C++ programs, like "this function never leaks memory" or "this program never attempts to divide by zero" or "this buffer never overflows" or to verify pointer arithmetic, etc.
Pro Free and open-source compiler
The compiler (ATS/Postiats) is GPLv3.
Pro Functional programming
The syntax is ML-like with the usual functional language features like pattern matching and tail-call optimization.
Pro High-performance systems language
ATS works as a low-level systems language. ATS programs have performance and footprint comparable to programs written in C/C++.
Pro Good module system
Similar to Modula-3. This makes ATS a viable choice even for large-scale projects.
Pro Safe concurrency
ATS can prove its concurrent programs have no deadlocks or race conditions.
Con Still in pre 1.0
Not very stable and has a rather small community.
Con No Windows version
But it does run on Cygwin.