Add support for constants

lib/options.go

@@ -5,8 +5,9 @@ type Option interface {
 }
 
 type config struct {
-	alphaSortTypes bool
-	alphaSortFuncs bool
+	alphaSortTypes     bool
+	alphaSortFuncs     bool
+	alphaSortConstants bool
 }
 
 func AlphaSortTypes() Option { return alphaSortTypes{} }
@@ -27,6 +28,15 @@ func (o alphaSortFuncs) apply(cfg *config) error {
 	return nil
 }
 
+func AlphaSortConstants() Option { return alphaSortConstants{} }
+
+type alphaSortConstants struct{}
+
+func (o alphaSortConstants) apply(cfg *config) error {
+	cfg.alphaSortConstants = true
+	return nil
+}
+
 func parseOptions(opts []Option) (config, error) {
 	cfg := config{}
 	for _, opt := range opts {

lib/outline.go

@@ -36,6 +36,7 @@ type Doc struct {
 	Description string
 	Functions   Functions
 	Types       Types
+	Constants   Constants
 }
 
 // Sort sorts all sortable fields in the document
@@ -46,6 +47,9 @@ func (d *Doc) Sort() {
 	if d.cfg.alphaSortTypes {
 		sort.Sort(d.Types)
 	}
+	if d.cfg.alphaSortConstants {
+		sort.Sort(d.Constants)
+	}
 }
 
 // Examples returns a slice of all examples defined in the document
@@ -208,3 +212,14 @@ type Example struct {
 	Description string
 	Code        string
 }
+
+type Constant struct {
+	Name        string
+	Description string
+}
+
+type Constants []*Constant
+
+func (c Constants) Len() int           { return len(c) }
+func (c Constants) Less(i, j int) bool { return c[i].Name < c[j].Name }
+func (c Constants) Swap(i, j int)      { c[i], c[j] = c[j], c[i] }

lib/parser.go

@@ -146,6 +146,10 @@ func (p *parser) readDocument(baseIndent int) (doc *Doc, err error) {
 			if doc.Types, err = p.readTypes(p.indent); err != nil {
 				return
 			}
+		case ConstantsTok:
+			if doc.Constants, err = p.readConstants(p.indent); err != nil {
+				return
+			}
 		case TextTok:
 			// only read descriptions when indented
 			if p.indent > baseIndent {
@@ -431,6 +435,33 @@ func (p *parser) readExample(baseIndent int) (eg *Example, err error) {
 	}
 }
 
+func (p *parser) readConstants(baseIndent int) (consts []*Constant, err error) {
+	for {
+		var c *Constant
+		if c, err = p.readConstant(baseIndent + 1); err != nil || c == nil {
+			return
+		}
+		consts = append(consts, c)
+	}
+}
+
+func (p *parser) readConstant(baseIndent int) (c *Constant, err error) {
+	tok := p.scan()
+	if p.indent < baseIndent || tok.Type != TextTok {
+		p.unscan()
+		return
+	}
+
+	// Split the token text into name and description based on the first colon.
+	parts := strings.SplitN(tok.Text, ":", 2)
+	if len(parts) != 2 {
+		return nil, fmt.Errorf("failed to parse constant: %s", tok.Text)
+	}
+
+	c = &Constant{Name: strings.TrimSpace(parts[0]), Description: strings.TrimSpace(parts[1])}
+	return
+}
+
 func (p *parser) errorf(format string, args ...interface{}) error {
 	return fmt.Errorf(format, args...)
 }

lib/parser_test.go

@@ -270,6 +270,20 @@ var withExamples = &Doc{
 	},
 }
 
+const withConstantsText = `outline: string
+	constants:
+        ascii_letters: A string containing all the characters that are considered letters.
+        digits: A string containing all characters considered decimal digits: '0123456789'
+`
+
+var withConstants = &Doc{
+	Name: "string",
+	Constants: []*Constant{
+		{Name: "ascii_letters", Description: "A string containing all the characters that are considered letters."},
+		{Name: "digits", Description: "A string containing all characters considered decimal digits: '0123456789'"},
+	},
+}
+
 func TestParse(t *testing.T) {
 	cases := []struct {
 		name string
@@ -286,6 +300,7 @@ func TestParse(t *testing.T) {
 		{"dataframe", dataframeTabs, dataframe, ""},
 		{"leading_and_trailing", ignoreOuterText, ignoreOuter, ""},
 		{"examples", withExamplesText, withExamples, ""},
+		{"constants", withConstantsText, withConstants, ""},
 	}
 
 	for _, c := range cases {

lib/scanner.go

@@ -80,6 +80,8 @@ func (s *scanner) Scan() Token {
 				return s.newTok(CodeTok)
 			case "examples":
 				return s.newTok(ExamplesTok)
+			case "constants":
+				return s.newTok(ConstantsTok)
 			default:
 				s.text.WriteRune(':')
 			}

lib/token.go

@@ -60,6 +60,8 @@ const (
 	MethodsTok
 	// OperatorsTok is the "operators:" token
 	OperatorsTok
+	// ConstantsTok is the "constants:" token
+	ConstantsTok
 	// KeywordEnd marks the end of keyword tokens in the token enumeration
 	KeywordEnd
 )