internal/prnt: doc exported symbols (#9)

internal/prnt/printer.go

@@ -5,36 +5,47 @@ import (
 	"fmt"
 )
 
+// Generator provides convenience methods for code generators. In particular it
+// provides fmt-like methods which print to an internal buffer. It also allows
+// any errors to be stored so they can be checked at the end, rather than having
+// error checks obscuring the code generation.
 type Generator struct {
 	buf bytes.Buffer
 	err error
 }
 
+// Printf prints to the internal buffer.
 func (g *Generator) Printf(format string, args ...interface{}) {
 	if g.err != nil {
 		return
 	}
-	if _, err := fmt.Fprintf(&g.buf, format, args...); err != nil {
-		g.AddError(err)
-	}
+	_, err := fmt.Fprintf(&g.buf, format, args...)
+	g.AddError(err)
 }
 
+// NL prints a new line.
 func (g *Generator) NL() {
 	g.Printf("\n")
 }
 
+// Comment writes comment lines prefixed with "// ".
 func (g *Generator) Comment(lines ...string) {
 	for _, line := range lines {
 		g.Printf("// %s\n", line)
 	}
 }
 
+// AddError records an error in code generation. The first non-nil error will
+// prevent printing operations from writing anything else, and the error will be
+// returned from Result().
 func (g *Generator) AddError(err error) {
 	if err != nil && g.err == nil {
 		g.err = err
 	}
 }
 
+// Result returns the printed bytes. If any error was recorded with AddError
+// during code generation, the first such error will be returned here.
 func (g *Generator) Result() ([]byte, error) {
 	return g.buf.Bytes(), g.err
 }