factor out func.go
diff --git a/func.go b/func.go
new file mode 100644
index 0000000..0d05664
--- /dev/null
+++ b/func.go
@@ -0,0 +1,48 @@
+package main
+
+import (
+ "fmt"
+ "os/exec"
+ "path/filepath"
+ "regexp"
+ "strings"
+)
+
+// Func is a make function.
+// http://www.gnu.org/software/make/manual/make.html#Functions
+// TODO(ukai): *Evaluator -> eval context or so?
+// TODO(ukai): return error instead of panic?
+type Func func(*Evaluator, string) string
+
+// http://www.gnu.org/software/make/manual/make.html#File-Name-Functions
+func funcWildcard(_ *Evaluator, arg string) string {
+ files, err := filepath.Glob(arg)
+ if err != nil {
+ panic(err)
+ }
+ return strings.Join(files, " ")
+}
+
+// http://www.gnu.org/software/make/manual/make.html#Shell-Function
+func funcShell(_ *Evaluator, arg string) string {
+ args := []string{"/bin/sh", "-c", arg}
+ cmd := exec.Cmd{
+ Path: args[0],
+ Args: args,
+ }
+ out, err := cmd.CombinedOutput()
+ if err != nil {
+ panic(err)
+ }
+ re, err := regexp.Compile(`\s`)
+ if err != nil {
+ panic(err)
+ }
+ return string(re.ReplaceAllString(string(out), " "))
+}
+
+// http://www.gnu.org/software/make/manual/make.html#Make-Control-Functions
+func funcWarning(ev *Evaluator, arg string) string {
+ fmt.Printf("%s:%d: %s\n", ev.filename, ev.lineno, arg)
+ return ""
+}