MapToSlice converts a map to slice.

Ptr returns a pointer to the value.

PtrDefToNil returns a pointer to the value, or nil if "def".

PtrZeroToNil returns a pointer to the value, or nil if "".

SafeIndex returns "s[i]" if possible, and 0 otherwise.

SafeIndexDef returns "s[i]" if possible, and "def" otherwise.

SafeIndexPtr returns "s[i]" if possible, and nil otherwise.

SliceToMap converts a slice to map.

Val returns the pointer value, defaulting to "" if nil.

ValDef returns the pointer value, defaulting to "def" if nil.

Slice is a slice of values.