Math functions from python as bash "builtins".

math.sh

#!/usr/bin/env bash

##
#
# @author Jay E. Taylor <jay@jaytaylor.com>
#
# @description Math functions for bash!
#
##

_create_python_based_math_funcs() {
    # 0-ary
    for func in math.e math.pi ; do
        eval "
${func/math\./}() {
    python -c '
import math, sys

sys.stdout.write(\"%s\\n\" % (${func},))
'
}
export -f ${func/math\./}" || echo "ERROR: defining func '${func/math\./}'" 1>&2
    done

    # unary
    for func in int float math.acos math.acosh math.asin math.asinh math.atan math.atan2 math.atanh math.ceil math.cos math.cosh math.degrees math.factorial math.floor math.gamma math.log math.log10 math.log1p math.modf math.radians math.sin math.sinh math.sqrt math.tan math.tanh ; do
        eval "
${func/math\./}() {
    python -c '
import math, sys

if len(sys.argv) > 1:
    map(lambda x: sys.stdout.write(\"%s\\n\" % (${func}(float(x.strip())),)), sys.argv[1:])
else:
    for x in sys.stdin:
        sys.stdout.write(\"%s\\n\" % (${func}(float(x.strip())),))
' \"\$@\"
}
export -f ${func/math\./}" || echo "ERROR: defining func '${func/math\./}'" 1>&2
    done

    # binary
    for func in math.pow math.fmod ; do
        eval "
${func/math\./}() {
    python -c '
import math, sys

if len(sys.argv) > 1:
    sys.stdout.write(\"%s\\n\" % (${func}(float(sys.argv[1].strip()), float(sys.argv[2].strip())),))
else:
    x, y = None, None
    for line in sys.stdin:
        if x is None:
            x = line.strip()
        else:
            y = line.strip()
        if None not in (x, y):
            if 0 not in (len(x), len(y)):
                sys.stdout.write(\"%s\\n\" % (${func}(float(x), float(y)),))
            x, y = None, None
' \"\$@\"
}
export -f ${func/math\./}" || echo "ERROR: defining func '${func/math\./}'" 1>&2
    done

    # n-ary
    for func in min max math.fsum ; do
        eval "
${func/math\./}() {
    python -c '
import math, sys

if len(sys.argv) > 1:
    args = sys.argv[1:]
else:
    args = sys.stdin.readlines()
sys.stdout.write(\"%s\\n\" % (${func}(map(lambda x: float(x.strip()), filter(lambda x: len(x.strip()) > 0, args))),))
' \"\$@\"
}
export -f ${func/math\./}" || echo "ERROR: defining func '${func/math\./}'" 1>&2
    done
}

_create_python_based_math_funcs
unset _create_python_based_math_funcs

#echo "$@"
if [ "${BASH_SOURCE[0]}" = "${0}" ] && [[ "$1{:-}" =~ tests? ]] ; then
    assert() {
        if [ -z "${2:-}" ] ; then
            echo 'ERROR: assert: missing operator' 1>&2
            echo '' 1>&2
            echo 'usage: assert [LHS] [OPERATOR] [RHS]' 1>&2
            echo '' 1>&2
            echo 'examples:' 1>&2
            echo '' 1>&2
            echo "    assert 2 '==' 3 // \$?=0 " 1>&2
            echo '' 1>&2
            echo "    assert hello '==' hello // \$?=0 " 1>&2
            echo '' 1>&2
            echo "    assert 4 '>' 3" 1>&2
            echo '    // output: ASSERTION FAILED: $1 not == $3' 1>&2
            echo '' 1>&2
            return 1
        fi

        local op

        op="$2"

        case "${op}" in
        =|==|eq)
            if [ "${1:-}" = "${3:-}" ] ; then
                return 0
            fi
            ;;
        '!='|ne)
            if [ "${1:-}" != "${3:-}" ] ; then
                return 0
            fi
            ;;
        '<'|lt)
            if [ "${1:-}" -lt "${3:-}" ] ; then
                return 0
            fi
            ;;
        '<='|le)
            if [ "${1:-}" -le "${3:-}" ] ; then
                return 0
            fi
            ;;

        '>'|gt)
            if [ "${1:-}" -gt "${3:-}" ] ; then
                return 0
            fi
            ;;
        '>='|ge)
            if [ "${1:-}" -ge "${3:-}" ] ; then
                return 0
            fi
            ;;
        *)
            echo "ERROR: assert: unrecognized operator: ${op}" 1>&2
            return 1
            ;;
        esac

        echo "ASSERTION FAILED: '${1:-}' not ${op} '${3:-}'" 1>&2
        return 1
    }
    export -f assert

    run_module_tests() {
        local rc

        rc=0

        assert "$(min 3 4)" '==' 3.0
        rc=$((rc+$?))

        assert "$(min 3 4 | int)" '==' 3
        rc=$((rc+$?))

        assert "$(min 19 3999 24 4)" '==' 4.0
        rc=$((rc+$?))

        assert "$(min 19 -4 3999 24 | int)" '==' -4
        rc=$((rc+$?))

        assert "$(max 3 4)" '==' 4.0
        rc=$((rc+$?))

        assert "$(max 19 3999 24 4)" '==' 3999.0
        rc=$((rc+$?))

        assert "$(floor 3.50001)" '==' 3.0
        rc=$((rc+$?))

        assert "$(ceil 3.50001)" '==' 4.0
        rc=$((rc+$?))

        assert "$(float 11)" '==' 11.0
        rc=$((rc+$?))

        assert "$(int 11.5)" '==' 11
        rc=$((rc+$?))

        assert "$(pow 2 5)" '==' 32.0
        rc=$((rc+$?))

        assert "$(fsum 1 2 3 4)" '==' 10.0
        rc=$((rc+$?))

        assert "$(echo -e "-1\n0\n99\n91239\n-01249" | min | int)" '==' -1249
        rc=$((rc+$?))

        assert "$(echo -e "   -1    \n      0\n99           \n	91239	\n	-01249" | min | int)" '==' -1249
        rc=$((rc+$?))

        assert "$(echo '3
                        4
                        5
                        6
                        7
                        ' | min)" '==' 3.0
        rc=$((rc+$?))

        assert "$(pi)" '==' 3.14159265359
        rc=$((rc+$?))

        assert "$(echo '4
                        5
                        6' | fmod)" '==' 4.0
        rc=$((rc+$?))

        if [ "${rc}" -ne 0 ] ; then
            echo "ERROR: 1 or more tests failed, rc=${rc}" 1>&2
            return "${rc}"
        fi

        echo 'INFO: All tests passed OK' 1>&2

    }
    export -f run_module_tests

    run_module_tests || echo "FAILED: test suite returned non-zero status code: $?" 1>&2
fi