Merge pull request #429 from LeGEC/426-add-func-and-bool-func

add support for Func() and BoolFunc() #426

1 files changed, 40 insertions, 0 deletions

diff --git a/bool_func.go b/bool_func.go
new file mode 100644
index 0000000..05783a9
--- /dev/null
+++ b/bool_func.go
@@ -0,0 +1,40 @@
+package pflag
+
+// -- func Value
+type boolfuncValue func(string) error
+
+func (f boolfuncValue) Set(s string) error { return f(s) }
+
+func (f boolfuncValue) Type() string { return "func" }
+
+func (f boolfuncValue) String() string { return "" } // same behavior as stdlib 'flag' package
+
+func (f boolfuncValue) IsBoolFlag() bool { return true }
+
+// BoolFunc defines a func flag with specified name, callback function and usage string.
+//
+// The callback function will be called every time "--{name}" (or any form that matches the flag) is parsed
+// on the command line.
+func (f *FlagSet) BoolFunc(name string, usage string, fn func(string) error) {
+	f.BoolFuncP(name, "", usage, fn)
+}
+
+// BoolFuncP is like BoolFunc, but accepts a shorthand letter that can be used after a single dash.
+func (f *FlagSet) BoolFuncP(name, shorthand string, usage string, fn func(string) error) {
+	var val Value = boolfuncValue(fn)
+	flag := f.VarPF(val, name, shorthand, usage)
+	flag.NoOptDefVal = "true"
+}
+
+// BoolFunc defines a func flag with specified name, callback function and usage string.
+//
+// The callback function will be called every time "--{name}" (or any form that matches the flag) is parsed
+// on the command line.
+func BoolFunc(name string, usage string, fn func(string) error) {
+	CommandLine.BoolFuncP(name, "", usage, fn)
+}
+
+// BoolFuncP is like BoolFunc, but accepts a shorthand letter that can be used after a single dash.
+func BoolFuncP(name, shorthand string, fn func(string) error, usage string) {
+	CommandLine.BoolFuncP(name, shorthand, usage, fn)
+}