internal/gen: doc exported symbols (#9)

internal/gen/gen.go

@@ -7,16 +7,20 @@ import (
 	"github.com/mmcloughlin/avo/printer"
 )
 
+// Interface of an instruction code generator.
 type Interface interface {
 	Generate([]inst.Instruction) ([]byte, error)
 }
 
+// Func adapts a function to Interface.
 type Func func([]inst.Instruction) ([]byte, error)
 
+// Generate calls f.
 func (f Func) Generate(is []inst.Instruction) ([]byte, error) {
 	return f(is)
 }
 
+// Builder constructs a code generator.
 type Builder func(printer.Config) Interface
 
 // GoFmt formats Go code produced from the given generator.