Improved code layout

src/build/compile.go

@@ -0,0 +1,51 @@
+package build
+
+import (
+	"sync"
+)
+
+// compile waits for all functions to finish compilation.
+func compile(functions <-chan *Function, errors <-chan error) (map[string]*Function, error) {
+	allFunctions := map[string]*Function{}
+
+	for functions != nil || errors != nil {
+		select {
+		case err, ok := <-errors:
+			if !ok {
+				errors = nil
+				continue
+			}
+
+			return nil, err
+
+		case function, ok := <-functions:
+			if !ok {
+				functions = nil
+				continue
+			}
+
+			allFunctions[function.Name] = function
+		}
+	}
+
+	wg := sync.WaitGroup{}
+
+	for _, function := range allFunctions {
+		wg.Add(1)
+
+		go func() {
+			defer wg.Done()
+			function.Compile()
+		}()
+	}
+
+	wg.Wait()
+
+	for _, function := range allFunctions {
+		if function.Error != nil {
+			return nil, function.Error
+		}
+	}
+
+	return allFunctions, nil
+}