Converting to and from external representations
Variable *PRECISION* Default precision.
Macro WITH-PRECISION Evalute BODY with *precision* bound to PREC.
Function DECIMAL-FROM-FLOAT Convert FLOAT to an exact value with precision PRECISION using
ROUNDING-METHOD to do any neccessary rounding.
Function FLOAT-FROM-DECIMAL Convert the exact decimal value DECIMAL to a (not neccassily
equal) floating point value.
Function ROUND-DOWN Round towards 0.
Function ROUND-HALF-UP Round towards the nearest value allowed with the current
Function ROUND-HALF-EVEN Round towards the nearest value allowed with the current
Function ROUND-CEILING Round towards positive infintity
Function ROUND-FLOOR Round towards negative infinity.
Function ROUND-HALF-DOWN Round towards the nearest legal value.
Function ROUND-UP Round away from 0.