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This is an interim step towards supporting relative imports. Previously, the IMPORT_VARIABLE instruction had a constant string operand for the import string of the module to import the variable from. However, with relative imports, the import string needs to be resolved by the host all into a canonical import string. At that point, the original import string in the source is no longer useful. This changes that to have IMPORT_VARIABLE access the imported ObjModule directly. It works in two pieces: 1. When a module is compiled, it ends with an END_MODULE instruction. That instruction stores the current ObjModule in vm->lastModule. 2. The IMPORT_VARIABLE instruction uses vm->lastModule as the module to load the variable from. Since no interesting code can execute between when a module body completes and the subsequent IMPORT_VARIABLE statements, we know vm->lastModule will be the one we imported.
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!
