Scala does tail recursion optimisation at compile-time, as other posters have said. That is, a tail recursive function is transformed into a loop by the compiler (a method invoke is transformed into a jump), as can be seen from the stack trace when running a tail recursive function. Try the following snippet: def boom(n: Int): … Read more
A simple tail recursive function: unsigned int f( unsigned int a ) { if ( a == 0 ) { return a; } return f( a – 1 ); // tail recursion } Tail recursion is basically when: there is only a single recursive call that call is the last statement in the function And … Read more
Let’s use the example code from the other question. Compile it, but tell gcc not to assemble: gcc -std=c99 -S -O2 test.c Now let’s look at the _atoi function in the resultant test.s file (gcc 4.0.1 on Mac OS 10.5): .text .align 4,0×90 _atoi: pushl %ebp testl %eax, %eax movl %esp, %ebp movl %eax, %ecx … Read more
I think it may be ASLR at work. You can turn off DEP to test this theory. See here for a C# utility class to check memory information: https://stackoverflow.com/a/8716410/552139 By the way, with this tool, I found that the difference between the maximum and minimum stack size is around 2 KiB, which is half a … Read more
Church Turing thesis highlights the equivalence between different computability models. Using recursion we don’t need a mutable state while solving some problem, and this make possible to specify a semantic in simpler terms. Thus solutions can be simpler, in a formal sense. I think that Prolog shows better than functional languages the effectiveness of recursion … Read more
Welcome to the world of lazy evaluation. When you think about it in terms of strict evaluation, foldl looks “good” and foldr looks “bad” because foldl is tail recursive, but foldr would have to build a tower in the stack so it can process the last item first. However, lazy evaluation turns the tables. Take, … Read more
The ECMAScript 4 specification was originally going to add support for TCO, but it was dropped: No more tail calls in JavaScript? As far as I know, no widely-available implementations of JavaScript currently do automatic TCO. This may be of use to you, though: Tail Call Optimization Essentially, using the accumulator pattern accomplish the same … Read more
No, Ruby doesn’t perform TCO. However, it also doesn’t not perform TCO. The Ruby Language Specification doesn’t say anything about TCO. It doesn’t say you have to do it, but it also doesn’t say you can’t do it. You just can’t rely on it. This is unlike Scheme, where the Language Specification requires that all … Read more
Update: As of January 1, 2020 Safari is the only browser that supports tail call optimization. The chromium team explicitly states that Tail Call Optimization is not under active development and can be tracked here. The implementation for Firefox can be tracked here Original Post Yes, ES2015 offers tail call optimization in strict mode. Dr. … Read more
This post: Recursion or Iteration? might help. In short, tail call optimization is hard to do in the JVM because of the security model and the need to always have a stack trace available. These requirements could in theory be supported, but it would probably require a new bytecode (see John Rose’s informal proposal). There … Read more