Fix type coercion rules

[Dimitar Misev]

The following changes need to be implemented in source:catalogmgr/ops.cc in order to make the type coercion rules more consistent. It will require updating oracles in the systemtest as well.

+, -, *

Type coercion rules are now

Should be

div

• Floating point operands should be supported
• Type rules should be same as above for +, -, *

mod

• Floating point operands should be supported (use std::remainder in code)
• Type rules should be mostly like +, -, *, except that the result is f only if both operands are floating point

abs

• Currently any operand results in a double
• The result should have the same type as the operand

sqrt, log, ln, exp, pow, sin, cos, tan, sinh, cosh, tanh, arcsin, arccos, arctan

• If both operands are f the result should be also float (now returns double in this case)

and, or, xor, not

• Should work as boolean logic operators on inputs of any type, including floating-point (currently they work as bitwise operators if inputs are not boolean)

count_cells

• Result type should be long instead of unsigned long

add_cells

• For signed/unsigned integer input the result should be long

[Dimitar Misev]

The rules are now in place and documented at ​http://doc.rasdaman.org/04_ql-guide.html#type-coercion-rules