chapter9/s_expressions.c
lval lval_err(int x){
    lval v;
    v.type = LVAL_ERR;
    v.err = x;
    return v;
}
/* Create a new error type lval */
Create a new error type lval
Create a new error type lval
lval lval_err(int x){
    lval v;
    v.type = LVAL_ERR;
    v.err = x;
    return v;
}
lval lval_err ( int x ) { lval v ; v . type = LVAL_ERR ; v . err = x ; return v ; }
Create a new error type lval
Create a new error type lval