feat: allow empty argument list methods in calls, definitions, and docs

- Compile empty `()` as a valid method signature distinct from no parentheses
- Update `call()`, `clear()`, `run()`, `try()`, and `yield()` to use empty argument lists
- Revise documentation across multiple files to reflect new signature semantics

test/fiber/abort.wren

@@ -2,6 +2,6 @@ var fiber = new Fiber {
   Fiber.abort("Error message.")
 }
 
-IO.print(fiber.try) // expect: Error message.
+IO.print(fiber.try()) // expect: Error message.
 IO.print(fiber.isDone) // expect: true
 IO.print(fiber.error) // expect: Error message.

test/fiber/call.wren

@@ -3,5 +3,5 @@ var fiber = new Fiber {
 }
 
 IO.print("before") // expect: before
-fiber.call         // expect: fiber
+fiber.call()       // expect: fiber
 IO.print("after")  // expect: after

test/fiber/call_direct_reenter.wren

@@ -1,7 +1,7 @@
 var fiber
 
 fiber = new Fiber {
-  fiber.call // expect runtime error: Fiber has already been called.
+  fiber.call() // expect runtime error: Fiber has already been called.
 }
 
-fiber.call
+fiber.call()

test/fiber/call_indirect_reenter.wren

@@ -2,11 +2,11 @@ var a
 var b
 
 a = new Fiber {
-  b.call // expect runtime error: Fiber has already been called.
+  b.call() // expect runtime error: Fiber has already been called.
 }
 
 b = new Fiber {
-  a.call
+  a.call()
 }
 
-b.call
+b.call()

test/fiber/call_return_implicit_null.wren

@@ -2,5 +2,5 @@ var fiber = new Fiber {
   IO.print("fiber")
 }
 
-var result = fiber.call // expect: fiber
-IO.print(result)        // expect: null
+var result = fiber.call() // expect: fiber
+IO.print(result)          // expect: null

test/fiber/call_return_value.wren

@@ -3,5 +3,5 @@ var fiber = new Fiber {
   return "result"
 }
 
-var result = fiber.call // expect: fiber
-IO.print(result)        // expect: result
+var result = fiber.call() // expect: fiber
+IO.print(result)          // expect: result

test/fiber/call_when_done.wren

@@ -2,5 +2,5 @@ var fiber = new Fiber {
   IO.print("call")
 }
 
-fiber.call // expect: call
-fiber.call // expect runtime error: Cannot call a finished fiber.
+fiber.call() // expect: call
+fiber.call() // expect runtime error: Cannot call a finished fiber.

test/fiber/closure.wren

@@ -5,9 +5,9 @@ var closure
   var a = "before"
   fiber = new Fiber {
     IO.print(a)
-    Fiber.yield
+    Fiber.yield()
     a = "after"
-    Fiber.yield
+    Fiber.yield()
     IO.print(a)
     a = "final"
   }
@@ -17,9 +17,9 @@ var closure
   }
 }
 
-fiber.call   // expect: before
-closure.call // expect: before
-fiber.call
-closure.call // expect: after
-fiber.call   // expect: after
-closure.call // expect: final
+fiber.call()   // expect: before
+closure.call() // expect: before
+fiber.call()
+closure.call() // expect: after
+fiber.call()   // expect: after
+closure.call() // expect: final

test/fiber/error.wren

@@ -3,5 +3,5 @@ var fiber = new Fiber {
 }
 
 IO.print(fiber.error) // expect: null
-IO.print(fiber.try)   // expect: String does not implement 'unknown'.
+IO.print(fiber.try()) // expect: String does not implement 'unknown'.
 IO.print(fiber.error) // expect: String does not implement 'unknown'.

test/fiber/is_done.wren

@@ -1,11 +1,11 @@
 var fiber = new Fiber {
   IO.print("1")
-  Fiber.yield
+  Fiber.yield()
   IO.print("2")
 }
 
 IO.print(fiber.isDone)  // expect: false
-fiber.call              // expect: 1
+fiber.call()            // expect: 1
 IO.print(fiber.isDone)  // expect: false
-fiber.call              // expect: 2
+fiber.call()            // expect: 2
 IO.print(fiber.isDone)  // expect: true

test/fiber/is_done_after_error.wren

@@ -2,5 +2,5 @@ var fiber = new Fiber {
   "s".unknown
 }
 
-fiber.try
+fiber.try()
 IO.print(fiber.isDone) // expect: true

test/fiber/resume_caller.wren

@@ -4,12 +4,12 @@ var b = new Fiber {
 
 var a = new Fiber {
   IO.print("begin fiber a")
-  b.call
+  b.call()
   IO.print("end fiber a")
 }
 
 IO.print("begin main")
-a.call
+a.call()
 IO.print("end main")
 
 // expect: begin main

test/fiber/run.wren

@@ -3,7 +3,7 @@ var fiber = new Fiber {
 }
 
 IO.print("before") // expect: before
-fiber.run          // expect: fiber
+fiber.run()        // expect: fiber
 
 // This does not get run since we exit when the run fiber completes.
 IO.print("nope")

test/fiber/run_direct_reenter.wren

@@ -2,9 +2,9 @@ var fiber
 
 fiber = new Fiber {
   IO.print(1) // expect: 1
-  fiber.run
+  fiber.run()
   IO.print(2) // expect: 2
 }
 
-fiber.call
+fiber.call()
 IO.print(3) // expect: 3

test/fiber/run_indirect_reenter.wren

@@ -3,17 +3,17 @@ var b
 
 a = new Fiber {
   IO.print(2)
-  b.run
+  b.run()
   IO.print("nope")
 }
 
 b = new Fiber {
   IO.print(1)
-  a.run
+  a.run()
   IO.print(3)
 }
 
-b.call
+b.call()
 // expect: 1
 // expect: 2
 // expect: 3

test/fiber/run_when_done.wren

@@ -5,9 +5,9 @@ var a = new Fiber {
 // Run a through an intermediate fiber since it will get discarded and we need
 // to return to the main one after a completes.
 var b = new Fiber {
-  a.run
+  a.run()
   IO.print("nope")
 }
 
-b.call // expect: run
-a.run // expect runtime error: Cannot run a finished fiber.
+b.call() // expect: run
+a.run()  // expect runtime error: Cannot run a finished fiber.

test/fiber/run_with_value_direct_reenter.wren

@@ -6,5 +6,5 @@ fiber = new Fiber {
   IO.print(2) // expect: 2
 }
 
-fiber.call
+fiber.call()
 IO.print(3) // expect: 3

test/fiber/run_with_value_indirect_reenter.wren

@@ -13,7 +13,7 @@ b = new Fiber {
   IO.print(3)
 }
 
-b.call
+b.call()
 // expect: 1
 // expect: 2
 // expect: 3

test/fiber/try.wren

@@ -4,7 +4,7 @@ var fiber = new Fiber {
   IO.print("after")
 }
 
-IO.print(fiber.try)
+IO.print(fiber.try())
 // expect: before
 // expect: Bool does not implement 'unknownMethod'.
 IO.print("after try") // expect: after try

test/fiber/try_direct_reenter.wren

@@ -1,7 +1,7 @@
 var fiber
 
 fiber = new Fiber {
-  fiber.try // expect runtime error: Fiber has already been called.
+  fiber.try() // expect runtime error: Fiber has already been called.
 }
 
-fiber.call
+fiber.call()

test/fiber/try_indirect_reenter.wren

@@ -2,11 +2,11 @@ var a
 var b
 
 a = new Fiber {
-  b.try // expect runtime error: Fiber has already been called.
+  b.try() // expect runtime error: Fiber has already been called.
 }
 
 b = new Fiber {
-  a.call
+  a.call()
 }
 
-b.call
+b.call()

test/fiber/try_when_done.wren

@@ -2,5 +2,5 @@ var fiber = new Fiber {
   IO.print("try")
 }
 
-fiber.try // expect: try
-fiber.try // expect runtime error: Cannot try a finished fiber.
+fiber.try() // expect: try
+fiber.try() // expect runtime error: Cannot try a finished fiber.

test/fiber/try_without_error.wren

@@ -2,7 +2,7 @@ var fiber = new Fiber {
   IO.print("fiber")
 }
 
-IO.print("before")  // expect: before
-IO.print(fiber.try) // expect: fiber
-                    // expect: null
-IO.print("after")   // expect: after
+IO.print("before")    // expect: before
+IO.print(fiber.try()) // expect: fiber
+                      // expect: null
+IO.print("after")     // expect: after

test/fiber/yield.wren

@@ -1,14 +1,14 @@
 var fiber = new Fiber {
   IO.print("fiber 1")
-  Fiber.yield
+  Fiber.yield()
   IO.print("fiber 2")
-  Fiber.yield
+  Fiber.yield()
   IO.print("fiber 3")
 }
 
-var result = fiber.call // expect: fiber 1
-IO.print("main 1")  // expect: main 1
-result = fiber.call // expect: fiber 2
-IO.print("main 2")  // expect: main 2
-result = fiber.call // expect: fiber 3
-IO.print("main 3")  // expect: main 3
+var result = fiber.call() // expect: fiber 1
+IO.print("main 1")    // expect: main 1
+result = fiber.call() // expect: fiber 2
+IO.print("main 2")    // expect: main 2
+result = fiber.call() // expect: fiber 3
+IO.print("main 3")    // expect: main 3

test/fiber/yield_from_main.wren

@@ -1 +1 @@
-Fiber.yield // expect runtime error: No fiber to yield to.
+Fiber.yield() // expect runtime error: No fiber to yield to.

test/fiber/yield_return_call_value.wren

@@ -1,14 +1,14 @@
 var fiber = new Fiber {
   IO.print("fiber 1")
-  var result = Fiber.yield
+  var result = Fiber.yield()
   IO.print(result)
-  result = Fiber.yield
+  result = Fiber.yield()
   IO.print(result)
 }
 
-fiber.call // expect: fiber 1
+fiber.call() // expect: fiber 1
 IO.print("main 1") // expect: main 1
 fiber.call("call 1") // expect: call 1
 IO.print("main 2") // expect: main 2
-fiber.call // expect: null
+fiber.call() // expect: null
 IO.print("main 3") // expect: main 3

test/fiber/yield_return_run_value.wren

@@ -1,10 +1,10 @@
 var fiber = new Fiber {
   IO.print("fiber")
-  var result = Fiber.yield
+  var result = Fiber.yield()
   IO.print(result)
 }
 
-fiber.call // expect: fiber
+fiber.call() // expect: fiber
 IO.print("main") // expect: main
 fiber.run("run") // expect: run
 

test/fiber/yield_with_no_caller.wren

@@ -1,9 +1,9 @@
 var a = new Fiber {
-  Fiber.yield // expect runtime error: No fiber to yield to.
+  Fiber.yield() // expect runtime error: No fiber to yield to.
 }
 
 // Run a chain of fibers. Since none of them are called, they all get discarded
 // and there is no remaining caller.
-var b = new Fiber { a.run }
-var c = new Fiber { b.run }
-c.run
+var b = new Fiber { a.run() }
+var c = new Fiber { b.run() }
+c.run()

test/fiber/yield_with_value.wren

@@ -6,9 +6,9 @@ var fiber = new Fiber {
   IO.print("fiber 3")
 }
 
-var result = fiber.call // expect: fiber 1
+var result = fiber.call() // expect: fiber 1
 IO.print(result) // expect: yield 1
-result = fiber.call // expect: fiber 2
+result = fiber.call() // expect: fiber 2
 IO.print(result) // expect: yield 2
-result = fiber.call // expect: fiber 3
+result = fiber.call() // expect: fiber 3
 IO.print(result) // expect: null

test/fiber/yield_with_value_with_no_caller.wren

@@ -4,6 +4,6 @@ var a = new Fiber {
 
 // Run a chain of fibers. Since none of them are called, they all get discarded
 // and there is no remaining caller.
-var b = new Fiber { a.run }
-var c = new Fiber { b.run }
-c.run
+var b = new Fiber { a.run() }
+var c = new Fiber { b.run() }
+c.run()