hussar-lang/hussar

package evaluator

import (
    "github.com/hussar-lang/hussar/object"
)

var builtins = map[string]*object.Builtin{
    "len": &object.Builtin{
        Fn: func(args ...object.Object) object.Object {
            if len(args) != 1 {
                return newError("error", "Wrong number of arguments passed to `len`. Expected: %d, got: %d", 1, len(args))
            }

            switch arg := args[0].(type) {
            case *object.String:
                return &object.Integer{Value: int64(len(arg.Value))}
            default:
                return newError("error", "Argument %s is not supported by `len`", args[0].Type())
            }
        },
    },
}