Format .edn files; add config option to select file extensions

Author: cespare

README.md

@@ -169,6 +169,14 @@ This is a Clojure file containing a single map of options. Here's an example:
 
 The configuration map may use the following keys:
 
+### :extensions
+
+This is a list of file extensions to format when cljfmt walks a directory.
+
+If not set, the default list of extensions is
+
+    (".clj" ".cljs" ".cljc" ".edn")
+
 ### :indent-overrides
 
 This is used to customize the indentation rules that cljfmt applies to

cljfmt/cljfmt.go

@@ -28,6 +28,7 @@ See the goclj README for more documentation of the available transforms.`)
 }
 
 type config struct {
+	extensions           map[string]struct{}
 	indentOverrides      map[string]format.IndentStyle
 	threadFirstOverrides map[string]format.ThreadFirstStyle
 	transforms           map[format.Transform]bool
@@ -42,6 +43,12 @@ func main() {
 		p: defaultConfigPath(),
 	}
 	conf := config{
+		extensions: map[string]struct{}{
+			".clj":  {},
+			".cljs": {},
+			".cljc": {},
+			".edn":  {},
+		},
 		transforms: make(map[format.Transform]bool),
 	}
 	flag.Var(&configFile, "c", "path to config file")
@@ -234,10 +241,8 @@ func (c *config) walkDir(path string) {
 		if strings.HasPrefix(name, ".") {
 			return nil
 		}
-		for _, ext := range []string{".clj", ".cljs", ".cljc"} {
-			if strings.HasSuffix(name, ext) {
-				return c.processFile(path, nil)
-			}
+		if _, ok := c.extensions[filepath.Ext(name)]; ok {
+			return c.processFile(path, nil)
 		}
 		return nil // not a Clojure file
 	}

cljfmt/config.go

@@ -45,6 +45,19 @@ func (c *config) parseDotConfig(r io.Reader, name string) error {
 			continue
 		}
 		switch sym.Val {
+		case ":extensions":
+			c.extensions = make(map[string]struct{})
+			seq, err := sequence(m.Nodes[i+1])
+			if err != nil {
+				return err
+			}
+			for _, n := range seq {
+				ext, err := stringNode(n)
+				if err != nil {
+					return err
+				}
+				c.extensions[ext] = struct{}{}
+			}
 		case ":indent-overrides", ":thread-first-overrides":
 			seq, err := sequence(m.Nodes[i+1])
 			if err != nil {
@@ -74,6 +87,8 @@ func (c *config) parseDotConfig(r io.Reader, name string) error {
 					c.threadFirstOverrides[k] = style
 				}
 			}
+		default:
+			return fmt.Errorf("unknown configuration key %q", sym.Val)
 		}
 	}
 	return nil