Print some C++ expresions. -iFILE to include FILE, -I -L -l -E -D -S and -O will be passed as such to g++. More compiler flags can be passed via -f$FLAG or $CXXFLAGS environment variable. Example: cppexpr.sh -f-std=c++0x -imath.h -lm 'log2(8)'

cppexpr.sh

#!/bin/bash

incs=""
flags="$CXXFLAGS"
only_preproc=off
no_asm=off
no_space=off

if [ "$CXX" = "" ]; then
	CXX=g++
fi

while getopts i:I:L:l:W:O:D:SEnf: opt "$@"; do
	case $opt in
	I|L|l|W|O|D)
		flags="$flags -$opt$OPTARG"
		;;
	f)
		flags="$flags $OPTARG"
		;;
	S)
		no_asm=on
		;;
	E)
		only_preproc=on
		;;
	n)
		no_space=on
		;;
	i)
		incs="$incs
#include \"$OPTARG\""
		;;
	\?)
		echo "Invalid option: -$OPTARG" >&2
		exit 1
		;;
	esac
done

shift $((OPTIND - 1))

exprs=""
if [ $no_space = on ]; then
	for ex in "$@"; do
		exprs="$exprs<< ($ex) "
	done
else
	for ex in "$@"; do
		exprs="$exprs<< ($ex) << ' ' "
	done
fi
args="-x c++ -Wall -Werror $flags -"

{
cat << EOF
#include <iostream>
#include <iomanip>
#include <cmath>
$incs

using namespace std;

int main (int argc, char *argv[]) {
	std::cout $exprs<< std::endl;
	return 0;
}
EOF
} | if [ "$only_preproc" = on ]; then
	"$CXX" $args -E -o -
elif [ "$no_asm" = on ]; then
	"$CXX" $args -S -o -
else
	tmp=/tmp/cppexpr.$$.out
	"$CXX" $args -o $tmp - && {
		$tmp
		code=$?
		rm -f $tmp
		exit $code
	}
fi