Improve logging and error handling

- enable logging by default: debug was a bad name - it's error logging that I
  just want to hide in tests
- don't panic (all the time)
- use a logger. this allows us to add more information - like the path of the
  parsed file!

org/document.go

@@ -4,7 +4,9 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
+	"os"
 	"strings"
 )
 
@@ -19,7 +21,7 @@ type Document struct {
 	BufferSettings      map[string]string
 	DefaultSettings     map[string]string
 	Error               error
-	Debug               bool
+	Log                 *log.Logger
 }
 
 type Writer interface {
@@ -80,6 +82,7 @@ func NewDocument() *Document {
 		DefaultSettings: map[string]string{
 			"TODO": "TODO | DONE",
 		},
+		Log: log.New(os.Stderr, "go-org: ", 0),
 	}
 }
 
@@ -118,6 +121,12 @@ func (dIn *Document) Parse(input io.Reader) (d *Document) {
 
 func (d *Document) SetPath(path string) *Document {
 	d.Path = path
+	d.Log.SetPrefix(fmt.Sprintf("%s(%s): ", d.Log.Prefix(), path))
+	return d
+}
+
+func (d *Document) Silent() *Document {
+	d.Log = log.New(ioutil.Discard, "", 0)
 	return d
 }
 
@@ -196,9 +205,7 @@ func (d *Document) parseOne(i int, stop stopFn) (consumed int, node Node) {
 	if consumed != 0 {
 		return consumed, node
 	}
-	if d.Debug {
+	d.Log.Printf("Could not parse token %#v: Falling back to treating it as plain text.", d.tokens[i])
-		log.Printf("Could not parse token %#v: Falling back to treating it as plain text.", d.tokens[i])
-	}
 	m := plainTextRegexp.FindStringSubmatch(d.tokens[i].matches[0])
 	d.tokens[i] = token{"text", len(m[1]), m[2], m}
 	return d.parseOne(i, stop)

org/html.go

@@ -16,7 +16,7 @@ type HTMLWriter struct {
 	HighlightCodeBlock    func(source, lang string) string
 	FootnotesHeadingTitle string
 	htmlEscape            bool
-	debug                 bool
+	log                   *log.Logger
 }
 
 var emphasisTags = map[string][]string{
@@ -65,7 +65,7 @@ func (w *HTMLWriter) nodesAsString(nodes ...Node) string {
 }
 
 func (w *HTMLWriter) before(d *Document) {
-	w.debug = w.debug || d.Debug
+	w.log = d.Log
 }
 
 func (w *HTMLWriter) after(d *Document) {
@@ -362,7 +362,7 @@ func (w *HTMLWriter) writeNodeWithMeta(n NodeWithMeta) {
 		}
 	}
 	for _, attributes := range n.Meta.HTMLAttributes {
-		out = withHTMLAttributes(w.debug, out, attributes...) + "\n"
+		out = w.withHTMLAttributes(out, attributes...) + "\n"
 	}
 	if len(n.Meta.Caption) != 0 {
 		caption := ""
@@ -414,19 +414,15 @@ func (w *HTMLWriter) writeTableColumns(columns []Column, tag string) {
 	w.WriteString("</tr>\n")
 }
 
-func withHTMLAttributes(debug bool, input string, kvs ...string) string {
+func (w *HTMLWriter) withHTMLAttributes(input string, kvs ...string) string {
 	if len(kvs)%2 != 0 {
-		if debug {
+		w.log.Printf("withHTMLAttributes: Len of kvs must be even: %#v", kvs)
-			log.Printf("withHTMLAttributes: Len of kvs must be even: %#v", kvs)
-		}
 		return input
 	}
 	context := &h.Node{Type: h.ElementNode, Data: "body", DataAtom: atom.Body}
 	nodes, err := h.ParseFragment(strings.NewReader(strings.TrimSpace(input)), context)
 	if err != nil || len(nodes) != 1 {
-		if debug {
+		w.log.Printf("withHTMLAttributes: Could not extend attributes of %s: %v (%s)", input, nodes, err)
-			log.Printf("withHTMLAttributes: Could not extend attributes of %s: %v (%s)", input, nodes, err)
-		}
 		return input
 	}
 	out, node := strings.Builder{}, nodes[0]
@@ -435,9 +431,7 @@ func withHTMLAttributes(debug bool, input string, kvs ...string) string {
 	}
 	err = h.Render(&out, nodes[0])
 	if err != nil {
-		if debug {
+		w.log.Printf("withHTMLAttributes: Could not extend attributes of %s: %v (%s)", input, node, err)
-			log.Printf("withHTMLAttributes: Could not extend attributes of %s: %v (%s)", input, node, err)
-		}
 		return input
 	}
 	return out.String()

org/html_test.go

@@ -9,7 +9,7 @@ func TestHTMLWriter(t *testing.T) {
 	for _, path := range orgTestFiles() {
 		expected := fileString(path[:len(path)-len(".org")] + ".html")
 		reader, writer := strings.NewReader(fileString(path)), NewHTMLWriter()
-		actual, err := NewDocument().SetPath(path).Parse(reader).Write(writer)
+		actual, err := NewDocument().Silent().SetPath(path).Parse(reader).Write(writer)
 		if err != nil {
 			t.Errorf("%s\n got error: %s", path, err)
 			continue

org/keyword.go

@@ -2,9 +2,7 @@ package org
 
 import (
 	"bytes"
-	"fmt"
 	"io/ioutil"
-	"log"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -119,7 +117,10 @@ func parseKeyword(t token) Keyword {
 }
 
 func (d *Document) newInclude(k Keyword) (int, Node) {
-	resolve := func() Node { panic(fmt.Sprintf("bad include: '#+INCLUDE: %s'", k.Value)) }
+	resolve := func() Node {
+		d.Log.Printf("Bad include %#v", k)
+		return k
+	}
 	if m := includeFileRegexp.FindStringSubmatch(k.Value); m != nil {
 		path, kind, lang := m[1], m[2], m[3]
 		if !filepath.IsAbs(path) {
@@ -128,7 +129,8 @@ func (d *Document) newInclude(k Keyword) (int, Node) {
 		resolve = func() Node {
 			bs, err := ioutil.ReadFile(path)
 			if err != nil {
-				panic(fmt.Sprintf("bad include '#+INCLUDE: %s': %s", k.Value, err))
+				d.Log.Printf("Bad include %#v: %s", k, err)
+				return k
 			}
 			return Block{strings.ToUpper(kind), []string{lang}, d.parseRawInline(string(bs))}
 		}
@@ -143,16 +145,12 @@ func (d *Document) loadSetupFile(k Keyword) (int, Node) {
 	}
 	bs, err := ioutil.ReadFile(path)
 	if err != nil {
-		if d.Debug {
+		d.Log.Printf("Bad setup file: %#v: %s", k, err)
-			log.Printf("Bad setup file: %#v: %s", k, err)
-		}
 		return 1, k
 	}
 	setupDocument := NewDocument().Parse(bytes.NewReader(bs))
 	if err := setupDocument.Error; err != nil {
-		if d.Debug {
+		d.Log.Printf("Bad setup file: %#v: %s", k, err)
-			log.Printf("Bad setup file: %#v: %s", k, err)
-		}
 		return 1, k
 	}
 	for k, v := range setupDocument.BufferSettings {

org/org_test.go

@@ -14,7 +14,7 @@ func TestOrgWriter(t *testing.T) {
 	for _, path := range orgTestFiles() {
 		expected := fileString(path[:len(path)-len(".org")] + ".pretty_org")
 		reader, writer := strings.NewReader(fileString(path)), NewOrgWriter()
-		actual, err := NewDocument().SetPath(path).Parse(reader).Write(writer)
+		actual, err := NewDocument().Silent().SetPath(path).Parse(reader).Write(writer)
 		if err != nil {
 			t.Errorf("%s\n got error: %s", path, err)
 			continue