structs_ex

#!/bin/bash
#
# An example that illustrates `structs` and `constructors`.

readonly DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
. ${DIR}/../gobash


# `struct` and `constructor` are synonyms. In future examples, we will
# only use `struct` in text (but we really mean both at once).
function Request() {
        # Normal function arguments in bash.
        local -r url="${1}"
        shift 1

        # `make_` invocation differentiates a struct from other
        # functions. `make_` allocates an instance. The first
        # argument is the struct name (think of it as a type). struct
        # name can be anything, but we will always use $FUNCNAME
        # (which is `Request` in this example). Name is important when
        # associating methods with a struct (and we love
        # $FUNCNAME). The arguments that follow are the name and value
        # of a field.
        make_ $FUNCNAME \
              "url" "${url}"
}

# Creating a `Request` instance is trivial.
req=$(Request "https://www.google.com")

# We can print the value of a field.
$req url

# We can also update the value.
$req url "https://www.google.com/maps"
# Print again.
$req url

# Output of this script will be:
# https://www.google.com
# https://www.google.com/maps