echo '(+ 1 2 (+ 3 4) (+ 5 6) 7)' | calc.noam
I'm sorry, but looking at the above I just couldn't [not] notice the
Greenspun's Tenth Rule of Programming :)
The nice thing about that law is that it can easily be adapted to
your language of choice. Let's try the Haskell version, this time
with addition and multiplication :)
#!/usr/bin/noam
number : /[0-9]+/ ;
list : /\[/ number (/,/ number)* /\]/
{printf "%s" "$2$3" | tr '[]' '()' > $OUTPUT} ;
plus : /plus/ list
{printf "%s" $2 | sed 's/,/+/g' > $OUTPUT} ;
times : /times/ list
{printf "%s" $2 | sed 's/,/*/g' > $OUTPUT} ;
number : (plus | times)
{printf "%s\n" "$1" | bc > $OUTPUT} ;
main : number {echo "Result: " $1} ;
You can type:
echo "plus[1,2,times[plus[3,4],plus[5,6]],7]" | calctest2.noam
Then you get:
Result: 87
Best,
Maurício
