maxprim.cpp

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#include "xtended.hh"
#include "Text.hh"
#include <math.h>
#include "sigtyperules.hh"

#include "floats.hh"

class MaxPrim : public xtended
{

 public:
 
    MaxPrim() : xtended("max") {}
    
    virtual unsigned int arity () { return 2; }
    
    virtual bool    needCache ()    { return true; }
    
    virtual Type    infereSigType (const vector<Type>& types)
    {
        assert (types.size() == arity());
        interval i = types[0]->getInterval();
        interval j = types[1]->getInterval();
        return castInterval(types[0]|types[1], max(i,j));
    }
    
    virtual void    sigVisit (Tree sig, sigvisitor* visitor) {} 
    
    virtual int infereSigOrder (const vector<int>& args) 
    {
        assert (args.size() == arity());
        return max(args[0], args[1]);
    }

    
    virtual Tree    computeSigOutput (const vector<Tree>& args) 
    {
        double f,g; int i,j;
        
        assert (args.size() == arity());
        
        if (isDouble(args[0]->node(),&f)) {
        
            if (isDouble(args[1]->node(), &g)) {
                return tree(max(f, g));
            } else if (isInt(args[1]->node(),&j)) {
                return tree(max(f, double(j)));
            } else {
                return tree(symbol(), args[0], args[1]);
            }
                
        } else if (isInt(args[0]->node(),&i)) {
        
            if (isDouble(args[1]->node(), &g)) {
                return tree(max(double(i), g));
            } else if (isInt(args[1]->node(),&j)) {
                return tree(max(i, j));
            } else {
                return tree(symbol(), args[0], args[1]);
            }
                
        } else {
        
            return tree(symbol(), args[0], args[1]);
        }
    }
        
    virtual string  generateCode (Klass* klass, const vector<string>& args, const vector<Type>& types)
    {
        assert (args.size() == arity());
        assert (types.size() == arity());
            
        // generates code compatible with overloaded max
        int n0 = types[0]->nature();
        int n1 = types[1]->nature();
        if (n0==kReal) {
            if (n1==kReal) {
                // both are floats, no need to cast
                return subst("max($0, $1)", args[0], args[1]);
            } else {
                assert(n1==kInt); // second argument is not float, cast it to float
                return subst("max($0, $2$1)", args[0], args[1], icast());
            }
        } else if (n1==kReal) {
            assert(n0==kInt); // first not float but second is, cast first to float
            return subst("max($2$0, $1)", args[0], args[1], icast());
        } else {
            assert(n0==kInt);  assert(n1==kInt);   // both are integers, check for booleans
            int b0 = types[0]->boolean();
            int b1 = types[1]->boolean();
            if (b0==kNum) {
                if (b1==kNum) {
                    // both are integers, no need to cast
                    return subst("max($0, $1)", args[0], args[1]);
                } else {
                    assert(b1==kBool);    // second is boolean, cast to int
                    return subst("max($0, (int)$1)", args[0], args[1]);
                }
            } else if (b1==kNum) {
                assert(b0==kBool);    // first is boolean, cast to int
                return subst("max((int)$0, $1)", args[0], args[1], icast());
            } else {
                assert(b0==kBool); assert(b1==kBool);   // both are booleans, no need to cast
                return subst("max((int)$0, (int)$1)", args[0], args[1]);
            }
        }
    }
    
    virtual string  generateLateq (Lateq* lateq, const vector<string>& args, const vector<Type>& types)
    {
        assert (args.size() == arity());
        assert (types.size() == arity());
        
        Type t = infereSigType(types);
        return subst("\\max\\left( $0, $1 \\right)", args[0], args[1]);
    }
    
};


xtended* gMaxPrim = new MaxPrim();