initial

main.go

@@ -0,0 +1,116 @@
+package dimcli
+
+import (
+	"slices"
+	"encoding/json"
+	"fmt"
+	"os"
+	"reflect"
+	"runtime"
+	"strings"
+)
+
+// Help takes the string of the file that it is used (use the embed
+// package), and searches for the text "HELP STOP" in the code. Then it prints
+// the lines of code between.
+func Help(stringOfThisFile string) {
+	if !slices.Contains(os.Args, "--help") {
+		return
+	}
+	println()
+
+	var _, _, lineNumBegin, ok = runtime.Caller(1)
+	if !ok {
+		panic("could not get caller information")
+	}
+	var lines = strings.Split(stringOfThisFile, "\n")
+	for i := range lines { // platform independent
+		lines[i] = strings.TrimSuffix(lines[i], "\r")
+	}
+	lines = lines[lineNumBegin:]
+	for _, line := range lines {
+		if strings.Contains(line, "HELP STOP") {
+			break
+		}
+		println(line)
+	}
+	println()
+	os.Exit(0)
+}
+
+var position = 1
+func GetPositional[T any]() (out T) {
+	var t = reflect.TypeFor[T]()
+	if len(os.Args) <= position {
+		var bytes, err = json.Marshal(out)
+		if err != nil {
+			panic(
+				fmt.Sprintf(
+					"type %s cannot be marshalled",
+					t.Name(),
+				),
+			)
+		}
+		panic(
+			fmt.Sprintf(
+				"missing positional arg %d of type %s\nexample: %s",
+				position,
+				t.Name(),
+				string(bytes),
+			),
+		)
+	}
+
+	var err = json.Unmarshal([]byte(os.Args[position]), &out)
+	if err != nil {
+		panic(
+			fmt.Sprintf(
+				"failed parsing %s into arg %d of type %s",
+				os.Args[position],
+				position,
+				t.Name(),
+			),
+		)
+	}
+
+	position++
+	return out
+}
+
+func GetKeyed[T any](name string, otherwise T) (out T) {
+	var key = fmt.Sprintf("--%s", name)
+	var index = 0
+	for i, value := range os.Args {
+		if value == key {
+			index = i
+			break
+		}
+	}
+	if index == 0 {
+		return otherwise
+	}
+	if (index+1) >= len(os.Args) {
+		var t = reflect.TypeFor[T]()
+
+		panic(
+			fmt.Sprintf(
+				"did not get value for keyed arg --%s.\nexpected value of type %s, kind %s",
+				name,
+				t.Name(),
+				t.Kind(),
+			),
+		)
+	}
+	var err = json.Unmarshal(
+		[]byte(os.Args[index+1]),
+		&out,
+	)
+	if err != nil {
+		panic(err.Error())
+	}
+	return out
+}
+
+func Flag(name string) bool {
+	return slices.Contains(os.Args, fmt.Sprintf("--%s", name))
+}