The language: The calculator compiler accepts a language that is very similar to the grammar you handled in the previous lab. Basically, a program written in the calculator language is a list of statement. The only data type allowed is integer. Each statement is an expression that consists of variables, integer constants and operators $+,-,*,/,!,**$and $=,$as well as parenthesis. Variables don $$ t need to be declared before use, and variable names are case $-$insensitive$.$ The value of an undeclared variable in its first use is $0.$The operator $=$returns the value that is being assigned. The language also supports conditional expression $?.$Its format is $($ cond $\_$ expression $)?($ e