functions

function toupper {
    echo "$*" | tr '[a-z]' '[A-Z]'
}

# Check if switch $1 == $2
function _test_sw {
    [[ "x$1" == "x$2" ]]
}

# Check if switch $1 matches regexp $2
function _test_re {
    # it's important not to quote $2 here!
    [[ "x$1" =~ x$2 ]]
}

# Used by replace_cxxstd, remove_cxxstd
CXXSTD_REGEXP="[-/]std=c\+\+[0-9][0-9]"

# Search $3... for a switch matching $2 using $1 (_test_* above)
# If found, echo index (0 for $3, 1 for $4...) and return 0.
# Otherwise return 1.
function _find {
    local tester="$1"
    local sought="$2"
    local i
    shift 2
    for (( i=1 ; i <= $# ; i=i+1 ))
    do
        eval "local sw=\${$i}"
        if $tester "$sw" "$sought"
        then
            echo $(( i - 1 ))
            return 0
        fi
    done
    return 1
}

# Search $3... using $1 (_test_* above) for $2 and remove it
function _remove {
    local tester="$1"
    local todel="$2"
    shift 2
    local out=("$@")
    local idx
    idx=$(_find $tester "$todel" "$@") && unset out\[$idx\]
    echo "${out[@]}"
}

# Search $4... using $1 (_test_* above) for $2 and replace it with $3
function _replace {
    local tester="$1"
    local todel="$2"
    local toins="$3"
    shift 3
    local out=("$@")
    local idx
    idx=$(_find $tester "$todel" "$@") && out[$idx]="$toins"
    echo "${out[@]}"
}

# Usage:
# switches="$(remove_switch -DPIC $LL_BUILD)"
# It's important NOT to quote whichever compiler-arguments string you pass to
# remove_switch (LL_BUILD in the example above), just as it's important not to
# quote it when passing it to the compiler itself: bash must parse into
# separate tokens.
function remove_switch {
    _remove _test_sw "$@"
}

# Usage:
# switches="$(remove_match regexp $LL_BUILD)"
# This is a special case of remove_switch that removes a regular expression.
function remove_match {
    _remove _test_re "$@"
}

# Usage:
# switches="$(remove_cxxstd $LL_BUILD)"
# This is a special case of remove_match that removes -std=c++NN
# (or /std=c++NN, as for Microsoft)
function remove_cxxstd {
    remove_match "$CXXSTD_REGEXP" "$@"
}

# Usage:
# switches="$(replace_switch -DPIC -DPOC $LL_BUILD)"
# It's important NOT to quote whichever compiler-arguments string you pass to
# replace_switch (LL_BUILD in the example above), just as it's important not to
# quote it when passing it to the compiler itself: bash must parse into
# separate tokens.
function replace_switch {
    _replace _test_sw "$@"
}

# Usage:
# switches="$(replace_match regexp $LL_BUILD)"
# This is a special case of replace_switch that replaces a regular expression.
function replace_match {
    _replace _test_re "$@"
}

# Usage:
# switches="$(replace_cxxver -std=c++20 $LL_BUILD)"
# This is a special case of replace_match that replaces -std=c++NN
# (or /std=c++NN, as for Microsoft)
function replace_cxxstd {
    replace_match "$CXXSTD_REGEXP" "$@"
}

# Usage:
# cmake ... $(cmake_cxx_standard $LL_BUILD) ...
# If the passed set of switches contains -std=c++NN (or /std=c++NN), echo
# -DCMAKE_CXX_STANDARD=NN to cause CMake to set the relevant switch itself.
# Otherwise echo nothing.
function cmake_cxx_standard {
    local idx
    if idx=$(_find _test_re "$CXXSTD_REGEXP" "$@")
    then
        # Mac bash 3 doesn't support negative indexing from right end
        eval "local sw=\${$((idx+1))}"
        local veridx=$(( ${#sw} - 2 ))
        echo "-DCMAKE_CXX_STANDARD=${sw:$veridx}"
    fi
}