added runnable examples

1 files changed, 89 insertions, 0 deletions

diff --git a/example_test.go b/example_test.go
new file mode 100644
index 0000000..d2febf6
--- /dev/null
+++ b/example_test.go
@@ -0,0 +1,89 @@
+package arg
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/alexflint/go-arg"
+)
+
+// This example demonstrates basic usage
+func Example_Basic() {
+	// These are the args you would pass in on the command line
+	os.Args = []string{"./example", "--foo=hello", "--bar"}
+
+	var args struct {
+		Foo string
+		Bar bool
+	}
+	arg.MustParse(&args)
+	fmt.Println(args.Foo, args.Bar)
+}
+
+// This example demonstrates arguments that have default values
+func Example_DefaultValues() {
+	// These are the args you would pass in on the command line
+	os.Args = []string{"--help"}
+
+	var args struct {
+		Foo string
+		Bar bool
+	}
+	args.Foo = "default value"
+	arg.MustParse(&args)
+	fmt.Println(args.Foo, args.Bar)
+}
+
+// This example demonstrates arguments that are required
+func Example_RequiredArguments() {
+	// These are the args you would pass in on the command line
+	os.Args = []string{"--foo=1", "--bar"}
+
+	var args struct {
+		Foo string `arg:"required"`
+		Bar bool
+	}
+	arg.MustParse(&args)
+}
+
+// This example demonstrates positional arguments
+func Example_PositionalArguments() {
+	// These are the args you would pass in on the command line
+	os.Args = []string{"./example", "in", "out1", "out2", "out3"}
+
+	var args struct {
+		Input  string   `arg:"positional"`
+		Output []string `arg:"positional"`
+	}
+	arg.MustParse(&args)
+	fmt.Println("Input:", args.Input)
+	fmt.Println("Output:", args.Output)
+}
+
+// This example demonstrates arguments that have multiple values
+func Example_MultipleValues() {
+	// The args you would pass in on the command line
+	os.Args = []string{"--help"}
+
+	var args struct {
+		Database string
+		IDs      []int64
+	}
+	arg.MustParse(&args)
+	fmt.Printf("Fetching the following IDs from %s: %q", args.Database, args.IDs)
+}
+
+// This example shows the usage string generated by go-arg
+func Example_Usage() {
+	// These are the args you would pass in on the command line
+	os.Args = []string{"--help"}
+
+	var args struct {
+		Input    string   `arg:"positional"`
+		Output   []string `arg:"positional"`
+		Verbose  bool     `arg:"-v,help:verbosity level"`
+		Dataset  string   `arg:"help:dataset to use"`
+		Optimize int      `arg:"-O,help:optimization level"`
+	}
+	arg.MustParse(&args)
+}