--File ParserUtilities.mesa
--March 6, 1980 5:56 PM

DIRECTORY

ParserTypeDefs: FROM "ParserTypeDefs" USING [Point, Path, AppendPoint, PathLength],

ParserUtilityDefs: FROM "ParserUtilityDefs",

ParserInputDefs: FROM "ParserInputDefs" USING[GetChar, Peek, EOF];

ParserUtilities: PROGRAM

IMPORTS ParserInputDefs, ParserTypeDefs EXPORTS ParserUtilityDefs =
BEGIN OPEN ParserUtilityDefs;

RecoverFromError: PUBLIC ERROR [errorCode: PossibleError] = CODE;

InitUtilities: PUBLIC PROCEDURE RETURNS [BOOLEAN] =
BEGIN
RETURN [TRUE];
END;

FinishUtilities: PUBLIC PROCEDURE RETURNS [BOOLEAN] =
BEGIN
RETURN [TRUE];
END;

Blank: PUBLIC PROCEDURE =
BEGIN
WHILE TRUE DO
SELECT ParserInputDefs.Peek[] FROM
’(,’),’;,’-,ParserInputDefs.EOF,IN [’0..’9],IN [’A..’Z] => RETURN;
ENDCASE => [] ← ParserInputDefs.GetChar[];
ENDLOOP;
END;

Sep: PUBLIC PROCEDURE =
BEGIN
WHILE TRUE DO
SELECT ParserInputDefs.Peek[] FROM
’(,’),’;,’-,ParserInputDefs.EOF,IN [’0..’9] => RETURN;
ENDCASE => [] ← ParserInputDefs.GetChar[];
ENDLOOP;
END;

Semi: PUBLIC PROCEDURE RETURNS [BOOLEAN] =
BEGIN
answer: BOOLEAN ← FALSE;
Blank[];
IF ParserInputDefs.Peek[] = ’; THEN
BEGIN [] ← ParserInputDefs.GetChar[]; answer ← TRUE; Blank[]; END;
RETURN[answer];
END;

GetPath: PUBLIC PROCEDURE [a: ParserTypeDefs.Path] =
BEGIN
temp: CHARACTER;

Sep[];
WHILE (temp ← ParserInputDefs.Peek[]) IN [’0..’9] OR temp = ’- DO
ParserTypeDefs.AppendPoint[a,GetPoint[]];
Sep[];
ENDLOOP;
IF ParserTypeDefs.PathLength[a] = 0 THEN ERROR RecoverFromError[NullPath];
END;

Unsigned: PUBLIC PROCEDURE RETURNS [CARDINAL] =
BEGIN
someDigit: BOOLEAN ← FALSE;
ans: CARDINAL ← 0;
BigNum: CARDINAL = (LAST[CARDINAL]-9)/10;

Sep[];
WHILE (ans < BigNum) AND ParserInputDefs.Peek[] IN [’0..’9] DO
ans ← ans * 10 + (ParserInputDefs.GetChar[]-’0);
someDigit ← TRUE;
ENDLOOP;

IF ~someDigit THEN ERROR RecoverFromError[MissingUnsigned];
IF ParserInputDefs.Peek[] IN [’0..’9] THEN
ERROR RecoverFromError[NumberTooBig]
ELSE
RETURN[ans];
END;

UnsignedLong: PUBLIC PROCEDURE RETURNS [LONG CARDINAL] =
BEGIN
someDigit: BOOLEAN ← FALSE;
ans: LONG CARDINAL ← 0;
BigNum: LONG CARDINAL = (LAST[LONG CARDINAL]-9)/10;

Sep[];
WHILE (ans < BigNum) AND ParserInputDefs.Peek[] IN [’0..’9] DO
ans ← ans * 10 + (ParserInputDefs.GetChar[]-’0);
someDigit ← TRUE;
ENDLOOP;

IF ~someDigit THEN ERROR RecoverFromError[MissingUnsigned];
IF ParserInputDefs.Peek[] IN [’0..’9] THEN
ERROR RecoverFromError[NumberTooBig]
ELSE
RETURN[ans];
END;

Signed: PUBLIC PROCEDURE RETURNS [INTEGER] =
BEGIN
sign, someDigit: BOOLEAN ← FALSE;
ans: INTEGER ← 0;
BigNum: INTEGER = (LAST[INTEGER]-9)/10;

Sep[];
IF ParserInputDefs.Peek[] = ’- THEN
BEGIN
sign ← TRUE;
[] ← ParserInputDefs.GetChar[];
END;

WHILE (ans < BigNum) AND ParserInputDefs.Peek[] IN [’0..’9] DO
ans ← ans * 10 + (ParserInputDefs.GetChar[]-’0);
someDigit ← TRUE;
ENDLOOP;

IF ~someDigit THEN ERROR RecoverFromError[MissingSigned];
IF ParserInputDefs.Peek[] IN [’0..’9] THEN
ERROR RecoverFromError[NumberTooBig]
ELSE
RETURN[IF sign THEN -ans ELSE ans];
END;

SignedLong: PUBLIC PROCEDURE RETURNS [LONG INTEGER] =
BEGIN
sign, someDigit: BOOLEAN ← FALSE;
ans: LONG INTEGER ← 0;
BigNum: LONG INTEGER = (LAST[LONG INTEGER]-9)/10;

Sep[];
IF ParserInputDefs.Peek[] = ’- THEN
BEGIN
sign ← TRUE;
[] ← ParserInputDefs.GetChar[];
END;

WHILE (ans < BigNum) AND ParserInputDefs.Peek[] IN [’0..’9] DO
ans ← ans * 10 + (ParserInputDefs.GetChar[]-’0);
someDigit ← TRUE;
ENDLOOP;

IF ~someDigit THEN ERROR RecoverFromError[MissingSigned];
IF ParserInputDefs.Peek[] IN [’0..’9] THEN
ERROR RecoverFromError[NumberTooBig]
ELSE
RETURN[IF sign THEN -ans ELSE ans];
END;

GetPoint: PUBLIC PROCEDURE RETURNS [ParserTypeDefs.Point] =
BEGIN
ans: ParserTypeDefs.Point;
ans.x ← SignedLong[];
ans.y ← SignedLong[];
RETURN[ans];
END;

END.