README
¶
argjoy
Golang module allowing you to call a method using callbacks to translate arguments. Also allows optional arguments.
Extremely basic example:
package main
import (
"fmt"
"github.com/lunixbochs/argjoy"
)
// optC is just a variable name. The opt prefix is not required.
func test(a, b, optC int) int {
return a + b + optC
}
func main() {
aj := argjoy.NewArgjoy(argjoy.StrToInt)
// Enables optional arguments, where unpassed arguments are zeroed.
aj.Optional = true
// The following is effectively: out := test(1, 2, 0)
out, err := aj.Call(test, "1", "2")
if err != nil {
panic(err)
}
// out is []interface{} so you need to do a type assert
fmt.Println(out[0].(int))
}
Custom argument decoder example (use argjoy.StrToInt for a more robust version of this):
func strToInt(arg interface{}, vals []interface{}) (err error) {
if v, ok := val[0].(string); ok {
if a, ok := arg.(*int); ok {
*a, err = strconv.Atoi(v)
return
}
}
return argjoy.NoMatch
}
Why?
Reduces duplicate decoding logic. Repeated decoding like v, err := strconv.Atoi(); if err != nil is completely eliminated.
Type-safe command-line parsing. Flag, Cobra, etc only reduce to a list of strings, so the rest of the decoding was up to you.
Syscall argument decoding via metaprogramming (used in Usercorn).
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
var NoMatch = &NoMatchErr{}
Functions ¶
func IntToInt ¶
func IntToInt(arg interface{}, vals []interface{}) (err error)
Codec to convert between any builtin int types. Throws bounds and sign errors as appropriate.
func RadStrToInt ¶
func RadStrToInt(arg interface{}, vals []interface{}) error
Codec to convert radix notations like hex, octal, binary to int. Throws bounds and sign errors as appropriate.
Types ¶
type ArgCountErr ¶
type ArgCountErr struct {
// contains filtered or unexported fields
}
func (ArgCountErr) Error ¶
func (e ArgCountErr) Error() string
type Argjoy ¶
type Argjoy struct {
Codecs []CodecFunc
// Determines whether unpassed arguments are optional.
// If this is false, invoking Call() with insufficient number of arguments
// will return ArgCountErr
Optional bool
}
func (*Argjoy) Call ¶
Call fn(vals...), using registered codecs to convert argument types. Returns []interface{} of target function's return values. Will return an error value if any codec fails. Panics if fn is not a valid function.
func (*Argjoy) Convert ¶
func (a *Argjoy) Convert(in []reflect.Type, variadic bool, vals ...interface{}) ([]reflect.Value, error)
Given the arguments to a function as per reflect.In(), produce a list of arguments suitable for invoking reflect.Call(fn, args). If fn is variadic, you must instead use reflect.CallSlice(fn, args).
type NoMatchErr ¶
type NoMatchErr struct {
// contains filtered or unexported fields
}
func (NoMatchErr) Error ¶
func (e NoMatchErr) Error() string
Source Files