bool Cond::eval(int var, const Func* fun) const {
int l = lhs->eval(var, fun);
int r = rhs->eval(var, fun);
switch (cmp) {
case LT: return l < r;
case GT: return l > r;
case EQ: return l == r;
default: throw 2;
}
}
int main()
{
Expr t = Expr("*", Expr("-", 5), Expr("+", 3, 4));
cout << t << " = " << t.eval() << endl;
cout << "((-5)*(3+4)) = -35" << endl;
t = Expr("*", t, t);
cout << t << " = " << t.eval() << endl;
cout << "(((-5)*(3+4))*((-5)*(3+4))) = 1225" << endl;
system("pause");
return 0;
}
int Table::query(const vector<string> &names, const Expr expr,
vector<vector<int> > &results) const {
int count = 0;
if (data.size() <= 0) {
return 0;
}
// get queried columns
if (std::find(names.begin(), names.end(), "*") != names.end()) { // all
for (const auto &record : data) {
if (expr.eval(record, indexes)) {
// columns occurring in the where clause (if any)
// should be in the schema of the table
results.push_back(record);
count++;
}
}
return count;
} else { // selected columns
// all columns (except *) in the select list should be in
// the schema of the table
for(const auto &name : names) {
if (std::find(columns.begin(), columns.end(), name)
== columns.end()) {
throw DataBaseError(string("Column ") + name
+ string(" is not in the schema"));
}
}
// use int index for reordering
vector<int> query_indexes;
for (const auto &name : names) {
auto it = indexes.find(name);
query_indexes.push_back(it->second);
}
for (const auto &record : data) {
if (expr.eval(record, indexes)) {
// columns occurring in the where clause (if any)
// should be in the schema of the table
vector<int> reordered;
for (const auto &idx : query_indexes) {
reordered.push_back(record[idx]);
}
results.push_back(reordered);
count++;
}
}
return count;
}
}
int main() {
Expr * e =
new Ap(
new Ap(
new Lam("x",
new Lam("y",
new Var("y"))),
new Val(new IntValue(5))),
new Val(new IntValue(3)));
shared_ptr<Value> v = e->eval({});
printf("%d\n", dynamic_pointer_cast<IntValue>(v)->getInt());
return 0;
}
int main() {
printf("\nCOMP6035 Coursework 2: Template Metaprogramming. \n"
"Part I -- Expression Templates\n"
"\nEvaluating expression x + (x-2) * (x-3), with x = 5 \n\n");
//Based on operator precedence (BODMAS), the expression is
//interpreted as x + ((x-2) * (x-3))
typedef ADD<X, MULT<SUB<X, LIT<2> >, SUB<X, LIT<3> > > > Expr;
Expr expr;
printf("Answer = %d\n\n", expr.eval(5));
return 0;
}
value_ptr Closure::apply(const std::vector<value_ptr>& actuals) const
{
// Checked by operator():
assert(actuals.size() == formals_.size());
Environment env = env_;
auto formal = formals_.begin();
auto actual = actuals.begin();
for (; formal != formals_.end(); ++formal, ++actual) {
env = env.extend(*formal, *actual);
}
return body_->eval(env);
}
int Table::del(const Expr expr) {
if (data.size() <= 0) {
return 0;
}
auto it = data.begin();
int count = 0;
// columns occurring in the where clause (if any)
// should be in the schema of the table
while (it != data.end()) {
if (expr.eval(*it, indexes)) {
it = data.erase(it);
count++;
} else {
it++;
}
}
return count;
}
int main( int argc, char *argv[] )
{
// Open the program's source.
if ( argc != 2 )
usage();
FILE *fp = fopen( argv[ 1 ], "r" );
if ( !fp ) {
fprintf( stderr, "Can't open file: %s\n", argv[ 1 ] );
usage();
}
// Parse the whole program source into an expression object.
// The parser uses a one-token lookahead to help parsing compound expressions.
char tok[ MAX_TOKEN + 1 ];
Expr *expr = parse( expectToken( tok, fp ), fp );
// If this is a legal input, there shouldn't be any extra tokens at the end.
if ( nextToken( tok, fp ) ) {
fprintf( stderr, "line %d: unexpected token \"%s\"\n", linesRead(), tok );
exit( EXIT_FAILURE );
}
fclose( fp );
// Run the program.
Context *ctxt = makeContext();
char *result = expr->eval( expr, ctxt );
// Everything evaluates to a dynamically allocated string, but we don't
// do anything with the one out of the top-level expression.
free( result );
// We're done, free everything.
freeContext( ctxt );
expr->destroy( expr );
return EXIT_SUCCESS;
}
S evaluate(const Expr & expr)
{
return expr.eval();
}
void display(Expr const& e){
cout << e << " = " << e.eval() << endl;
}
A(Expr expr):value(expr.eval()){}
int main() {
Expr::addFunction("sqr", sqr);
Expr::addFunction("len2", len2);
struct Test { const char *expr; int err; double result; } tests[] = {
{"1", -1, 1.0},
{"1+1", -1, 2.0},
{"3 * 4", -1, 12.0},
{"((1))", -1, 1.0},
{"3*--3", -1, 9.0},
{"1+2*(3+4)", -1, 15.0},
{"1+2*(3+4*(5+6.5))", -1, 99.0},
{"x1", -1, 100.0},
{"x1+y1*2", -1, 500},
{"1--1", -1, 2},
{"1/(8--8) ; this comment is ignored", -1, 0.0625},
{"1/;internal comment\n(8--8)", -1, 0.0625},
{"1<2", -1, 1.0},
{"1<=2", -1, 1.0},
{"1>2", -1, 0.0},
{"1>=2", -1, 0.0},
{"1==2", -1, 0.0},
{"1!=2", -1, 1.0},
{"1!=2", -1, 1.0},
{"!(2<1)", -1, 1.0},
{"!!2", -1, 1.0},
{"1<2 && 3<4", -1, 1.0},
{"1<2 && 3>4", -1, 0.0},
{"1<2 || 3<4", -1, 1.0},
{"1<2 || 3>4", -1, 1.0},
{"(0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1)!=1.0", -1, 1.0}, // Approximation!
{"1 | 2 == 3", -1, 1.0},
{"3 ^ 2 == 1", -1, 1.0},
{"3 ^ 1 == 2", -1, 1.0},
{"-1 & 7 == 7", -1, 1.0},
{"-1 >> 1 == -1", -1, 1.0},
{"-1 << 1 == -2", -1, 1.0},
{"(1 << 16)-1 >> 8 == 255", -1, 1.0},
{"abs(-1)", -1, 1.0},
{"cos(1-1)", -1, 1.0},
{"abs(cos(3.141592654 * 0.5)) < 1E-6", -1, 1.0},
{"cos()", 4, -1},
{"atan2(12)", 8, -1},
{"atan2(0, 1)", -1, 0},
{"abs(atan(1)-3.141592654/4) < 1E-6", -1, 1.0},
{"random() != 1.2", -1, 1.0},
{"abs(log(1024)/log(2) - 10) < 1E-6", -1, 1.0},
{"floor(pow(2, 8) + 0.5) == 256", -1, 1.0},
{"abs(sqrt(2)*sqrt(2) - 2) < 1E-6", -1, 1.0},
{"abs(tan(3.141592654/4)-1) < 1E-6", -1, 1.0},
{"abs(log(exp(13)) - 13) < 1E-6", -1, 1.0},
{"abs(len2(3,4) - 5) < 1E-6", -1, 1.0},
{"sqr(3) == 9", -1, 1.0},
{"1+z2*4", 4, -1},
{"1+2*", 4, -1},
{"1+(2*3", 6, -1},
{"1+2()", 3, -1},
{"+1", 0, -1},
};
std::map<std::string, double> vars;
vars["x0"] = 3.14;
vars["y0"] = 2.718;
vars["x1"] = 100;
vars["y1"] = 200;
int errors = 0;
int ntests = sizeof(tests)/sizeof(tests[0]);
for (int i=0; i<ntests; i++) {
double res = -1;
try {
Expr expr = Expr::parse(tests[i].expr, vars);
if (tests[i].err != -1) throw Expr::Error("Parsing should have failed");
res = expr.eval();
if (tests[i].result != res) throw Expr::Error("Unexpected result");
} catch (Expr::Error& err) {
if (tests[i].err == err.position) {
// Ok; parsing error position is correct
} else {
errors++;
printf("TEST FAILED: \"%s\" (err=%i, result=%0.3f) --> res=%0.3f\n%s (position=%i)\n\n",
tests[i].expr, tests[i].err, tests[i].result,
res, err.what(), err.position);
}
}
}
printf("%i errors on %i tests\n", errors, ntests);
int w=640, h=480;
vars["k"] = 10*3.141592654 / ((w*w+h*h)/4);
double& y = vars["y"];
double& x = vars["x"];
std::vector<unsigned char> img(w*h);
Expr e("((128 + sin(((x-320)*(x-320) + (y-240)*(y-240))*k)*127) ^"
" (255 * ((floor(x/128)+floor(y/96)) & 1))) + random()*32-16", vars);
printf("Expression compiled code:\n%s\n", e.disassemble().c_str());
clock_t start = clock();
for (int rep=0; rep<10; rep++) {
int i = 0;
for (y=0; y<h; y++) {
for (x=0; x<w; x++) {
int ie = int(e);
if (ie < 0) ie = 0; if (ie > 255) ie = 255;
img[i++] = ie;
}
}
}
clock_t stop = clock();
printf("Test image generated in %0.3fms (%.0f pixels/sec)\n",
(stop - start)*100.0/CLOCKS_PER_SEC,
double(w*h*10)*CLOCKS_PER_SEC/(stop-start+1));
FILE *f = fopen("test.pgm", "wb");
if (f) {
fprintf(f, "P5\n%i %i 255\n", w, h);
fwrite(&img[0], 1, w*h, f);
fclose(f);
} else {
fprintf(stderr, "Error generating test.pgm\n");
}
clock_t start2 = clock();
double k = vars["k"];
for (int rep=0; rep<10; rep++) {
int i = 0;
for (y=0; y<h; y++) {
for (x=0; x<w; x++) {
int ie = int(
(int(128 + sin(((x-320)*(x-320) + (y-240)*(y-240))*k)*127) ^
int(255 * (int(floor(x/128)+floor(y/96)) & 1))) + myrandom()*32-16);
if (ie < 0) ie = 0; if (ie > 255) ie = 255;
img[i++] = ie;
}
}
}
clock_t stop2 = clock();
printf("Test image generated natively in %0.3fms (%.0f pixels/sec)\n",
(stop2 - start2)*100.0/CLOCKS_PER_SEC,
double(w*h*10)*CLOCKS_PER_SEC/(stop2-start2+1));
f = fopen("test_native.pgm", "wb");
if (f) {
fprintf(f, "P5\n%i %i 255\n", w, h);
fwrite(&img[0], 1, w*h, f);
fclose(f);
} else {
fprintf(stderr, "Error generating test_native.pgm\n");
}
return errors != 0;
}