Real variables and constants:

real-prefix	:	empty
	|	REAL
	|	REAL CONST
	|	CONST

real-definition	:	real-prefix real-name = real-expression // expression evaluated
	|	real-prefix real-name := real-expression // expression ratained

symbolic-constant	:	PI
	|	TWOPI
	|	DEGRAD
	|	RADDEG
	|	E
	|	EMASS
	|	PMASS
	|	CLIGHT
	|	real-name

real-name	:	identifier

object-name	:	identifier

table-reference	:	table-name @ place -> column-name

table-name	:	identifier

column-name	:	identifier