In the context of command-line argument parsing using docopt, values stored in the resulting map are of the interface{} type, which can represent any type of data. However, when attempting to concatenate values from this map into a string, an error occurs due to type mismatch.
To address this issue, type assertion is required to convert the interface{} values to strings before concatenation. This is particularly important as the map is of type map[string]interface{}, where the values can vary in type.
The updated code would be as follows:
host := arguments["<host>"].(string) + ":" + arguments["<port>"].(string)
This type assertion explicitly converts the interface{} values to strings, ensuring successful concatenation.
Alternatively, in the latest version of docopt, the returned Opts object provides convenient methods for conversion:
host, err := arguments.String("<host>") port, err := arguments.String("<port>") host_port := host + ":" + port
These methods will handle the conversion to strings and return the converted values, simplifying the code and eliminating the need for type assertion in this case.
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