RatIntervalsImpl.mesa
Last Edited by: Arnon, July 19, 1985 2:54:46 pm PDT
DIRECTORY
Rope,
IO,
BigRats,
AlgebraClasses,
RatIntervals;
RatIntervalsImpl:
CEDAR
PROGRAM
IMPORTS Rope, IO, BigRats
EXPORTS RatIntervals
= BEGIN OPEN BR: BigRats, RatIntervals;
ReadRatInterval:
PUBLIC
PROC [in:
IO.
STREAM]
RETURNS [out: RatInterval] ~ {
puncChar: CHAR;
leftEndPoint, rightEndPoint: BR.BigRat;
[]← in.SkipWhitespace[];
puncChar ← in.GetChar[ ];
IF puncChar # '( THEN ERROR;
leftEndPoint ← NARROW[ BR.BigRats.class.read[in, BR.BigRats] ];
[]← in.SkipWhitespace[];
puncChar ← in.GetChar[ ];
IF puncChar # ', THEN ERROR;
rightEndPoint ← NARROW[ BR.BigRats.class.read[in, BR.BigRats] ];
[]← in.SkipWhitespace[];
puncChar ← in.GetChar[ ];
IF puncChar # ') THEN ERROR;
RETURN[NEW[RatIntervalRec ← [leftEndPoint, rightEndPoint] ] ];
};
RatIntervalFromRope:
PUBLIC
PROC [in: Rope.
ROPE]
RETURNS [out: RatInterval] = {
stream: IO.STREAM ← IO.RIS[in];
out ← ReadRatInterval[stream];
};
RatIntervalToRope:
PUBLIC
PROC [in: RatInterval, showDenomOne:
BOOL ←
FALSE]
RETURNS [out: Rope.
ROPE] ~ {
out ← "( ";
out ← Rope.Cat[out, BR.BigRats.class.toRope[in.leftEndPoint], " , "];
out ← Rope.Cat[out, BR.BigRats.class.toRope[in.rightEndPoint], " )"];
};
WriteRatInterval:
PUBLIC
PROC [in: RatInterval, out:
IO.
STREAM, showDenomOne:
BOOL ←
FALSE] ~ {
ratIntRope: Rope.ROPE ← RatIntervalToRope[in, showDenomOne];
out.PutF["%g\n", IO.rope[ratIntRope] ];
};
END.