Bob Nystrom
eecc18244f
In runtimeError, walk the entire fiber call chain and set each fiber's error field to the same error value, unhooking callers as we go. Previously only the immediate caller was considered, leaving intermediate fibers in an inconsistent state. This ensures that when a fiber aborts, every fiber in the chain up to (but not including) the one that catches the error via try() is properly marked as errored. Also remove the old nested fiber tests from try.wren and add a new comprehensive test (try_through_call.wren) that verifies the percolation behavior through multiple levels of fiber calls and confirms that intermediate fibers carry the error while the catching fiber and its callers remain clean.
Wren is a small, fast, class-based concurrent scripting language
Think Smalltalk in a Lua-sized package with a dash of Erlang and wrapped up in a familiar, modern syntax.
System.print("Hello, world!")
class Wren {
flyTo(city) {
System.print("Flying to %(city)")
}
}
var adjectives = Fiber.new {
["small", "clean", "fast"].each {|word| Fiber.yield(word) }
}
while (!adjectives.isDone) System.print(adjectives.call())
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Wren is small. The VM implementation is under 4,000 semicolons. You can skim the whole thing in an afternoon. It's small, but not dense. It is readable and lovingly-commented.
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Wren is fast. A fast single-pass compiler to tight bytecode, and a compact object representation help Wren compete with other dynamic languages.
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Wren is class-based. There are lots of scripting languages out there, but many have unusual or non-existent object models. Wren places classes front and center.
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Wren is concurrent. Lightweight fibers are core to the execution model and let you organize your program into an army of communicating coroutines.
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Wren is a scripting language. Wren is intended for embedding in applications. It has no dependencies, a small standard library, and an easy-to-use C API. It compiles cleanly as C99, C++98 or anything later.
If you like the sound of this, let's get started. You can even try it in your browser! Excited? Well, come on and get involved!
