shapes_ex

#!/bin/bash
#
# An example that illustrates `methods`.  The example introduces
# `structs` for Circle, Square, and Rectangle, as well as a
# `methods` for each of them for computing area.

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


function Circle() {
        [ $# -ne 1 ] && return $EC
        local -r r="${1}"
        shift 1

        make_ $FUNCNAME \
              "r" "${r}"
        # We do not need to return explicitly (because the
        # default output is the result of the last command, but
        # being explicit is good in some cases).
        # return $?
}

function Circle_area() {
        local -r c="${1}"
        shift 1

        local result
        result=$(echo "$MATH_PI * $($c r) * $($c r)" | bc)
        echo ${result}
        return 0
}

function Square() {
        [ $# -ne 1 ] && return $EC
        local -r a="${1}"
        shift 1

        make_ $FUNCNAME \
              "a" "${a}"
}

function Square_area() {
        local -r obj="${1}"
        shift 1

        local result
        result=$(( $($obj "a") * $($obj "a") ))
        echo ${result}
        return 0
}

function Rectangle() {
        [ $# -ne 2 ] && return $EC
        local -r a="${1}"
        local -r b="${2}"
        shift 2

        make_ $FUNCNAME \
              "a" "${a}" \
              "b" "${b}"
}

function Rectangle_area() {
        local -r obj="${1}"
        shift 1

        local result
        result=$(( $($obj "a") * $($obj "b") ))
        echo ${result}
        return 0
}

function main() {
        lst=$(List)

        c=$(Circle 4)
        $lst add "$c"

        s=$(Square 4)
        $lst add "$s"

        r=$(Rectangle 2 2)
        $lst add "$r"

        assert_eq $($lst len) 3

        local total=0
        local i
        for (( i=0; i<$($lst len); i++ )); do
                local el=$($lst get ${i})
                total=$(echo "$($el area) + ${total}" | bc -l)
        done
        printf "Total area: %g\n" ${total}
        assert_has_prefix "${total}" "70"
}

main