DIRECTORY RussellSyntax USING[TokType], IO USING[STREAM, GetChar, PeekChar, EndOf, Backup, TokenKind, SkipWhitespace, EndOfStream, GetCedarToken, DEL, NUL, SP], Rope USING[FromRefText], Atom USING[MakeAtomFromRefText], RefText USING[InlineAppendChar, Length]; RussellScannerImpl: CEDAR PROGRAM IMPORTS IO, Rope, Atom, RefText EXPORTS RussellSyntax = BEGIN OPEN RussellSyntax ; TokTypeFromAtom: PRIVATE PROCEDURE [name: ATOM] RETURNS [TokType] = BEGIN RETURN[ SELECT name FROM $tuple => tokKWtuple , $func => tokKWfunc , $proc => tokKWproc , $ref => tokKWref , $prod => tokKWprod , $union => tokKWunion , $if => tokKWif , $else => tokKWelse , $fi => tokKWfi , $do => tokKWdo , $od => tokKWod , $open => tokKWopen , $in => tokKWin , $ni => tokKWni , $lambda => tokKWlambda , $type => tokKWtype , $safetype => tokKWsafetype , ENDCASE => tokId ] END ; -- TokTypeFromAtom GetRussellToken: PUBLIC PROCEDURE [source: IO.STREAM, buffer: REF TEXT] RETURNS [tokType: TokType, tokVal: REF ANY _ NIL, charsRead: INT] = BEGIN c: CHAR; nRead: INT; nSkipped: INT; tokKind: IO.TokenKind; tokName: ATOM; scanBuf: REF TEXT _ buffer; BEGIN nRead _ IO.SkipWhitespace[stream~source !IO.EndOfStream => GOTO endOfFile ]; c _ source.GetChar[ !IO.EndOfStream => GOTO endOfFile ]; nRead _ nRead + 1; SELECT c FROM IN ['a .. 'z], IN ['A .. 'Z] => { source.Backup[c]; nRead _ nRead - 1; [tokenKind~tokKind, token~scanBuf, charsSkipped~nSkipped] _ IO.GetCedarToken[stream~source, buffer~buffer]; nRead _ nRead + nSkipped; IF tokKind # tokenERROR THEN nRead _ nRead + RefText.Length[scanBuf]; IF tokKind # tokenID THEN RETURN[tokType~tokError, charsRead~nRead] ; tokName _ Atom.MakeAtomFromRefText[scanBuf]; RETURN[tokType~TokTypeFromAtom[tokName], tokVal~tokName, charsRead~nRead] } ; IN ['0 .. '9], '', '" => { source.Backup[c]; nRead _ nRead - 1; [tokenKind~tokKind, token~scanBuf, charsSkipped~nSkipped] _ IO.GetCedarToken[stream~source, buffer~buffer]; nRead _ nRead + nSkipped; IF tokKind # tokenERROR THEN nRead _ nRead + RefText.Length[scanBuf]; SELECT tokKind FROM tokenDECIMAL, tokenOCTAL, tokenHEX => RETURN[tokType~tokIntConst, tokVal~Rope.FromRefText[scanBuf], charsRead~nRead] ; tokenCHAR => RETURN[tokType~tokCharConst, tokVal~Rope.FromRefText[scanBuf], charsRead~nRead] ; tokenROPE => RETURN[tokType~tokStringConst, tokVal~Rope.FromRefText[scanBuf], charsRead~nRead] ; ENDCASE => RETURN[tokType~tokError, charsRead~nRead] ; } ; '< => { IF (NOT source.EndOf[]) THEN BEGIN SELECT source.PeekChar[] FROM '* => { [] _ source.GetChar[]; nRead _ nRead+1; RETURN[tokType~tokLRecTupleBrak, charsRead~nRead]; } ; ENDCASE => NULL ; END ; RETURN[tokType~tokLTupleBrak, charsRead~nRead]; } ; '* => { IF (NOT source.EndOf[]) THEN BEGIN SELECT source.PeekChar[] FROM '> => { [] _ source.GetChar[]; nRead _ nRead+1; RETURN[tokType~tokRRecTupleBrak, charsRead~nRead]; } ; ENDCASE => NULL ; END ; } ; '= => { IF (NOT source.EndOf[]) THEN BEGIN SELECT source.PeekChar[] FROM '> => { [] _ source.GetChar[]; nRead _ nRead+1; RETURN[tokType~tokGuardArrow, charsRead~nRead]; } ; ENDCASE => NULL ; END ; } ; '- => { IF (NOT source.EndOf[]) THEN BEGIN SELECT source.PeekChar[] FROM '> => { [] _ source.GetChar[]; nRead _ nRead+1; RETURN[tokType~tokFunctionArrow, charsRead~nRead]; } ; ENDCASE => NULL ; END ; } ; '. => RETURN[tokType~tokSelect, charsRead~nRead] ; ', => RETURN[tokType~tokListSep, charsRead~nRead] ; '| => RETURN[tokType~tokConcat, charsRead~nRead] ; '? => RETURN[tokType~tokQuery, charsRead~nRead] ; '~ => RETURN[tokType~tokIsBoundTo, charsRead~nRead] ; '> => RETURN[tokType~tokRTupleBrak, charsRead~nRead] ; '; => RETURN[tokType~tokStmtSep, charsRead~nRead] ; ': => RETURN[tokType~tokHasType, charsRead~nRead] ; '[ => RETURN[tokType~tokLBrak, charsRead~nRead] ; '] => RETURN[tokType~tokRBrak, charsRead~nRead] ; '{ => RETURN[tokType~tokLUnionBrak, charsRead~nRead] ; '} => RETURN[tokType~tokRUnionBrak, charsRead~nRead] ; '( => RETURN[tokType~tokLParen, charsRead~nRead] ; ') => RETURN[tokType~tokRParen, charsRead~nRead] ; '# => RETURN[tokType~tokGuardedExpSep, charsRead~nRead] ; IO.DEL => RETURN[tokType~tokError, charsRead~nRead] ; ENDCASE => NULL ; scanBuf.length _ 0; scanBuf _ RefText.InlineAppendChar[scanBuf, c ]; DO c _ source.GetChar[ !IO.EndOfStream => EXIT ]; nRead _ nRead+1; SELECT c FROM IN [IO.NUL .. IO.SP], IN ['a .. 'z], IN ['A .. 'Z], IN ['0 .. '9], '', '", '<, '., ',, '|, '?, '~, '>, ';, ':, '[, '], '{, '}, '(, '), '#, IO.DEL => { source.Backup[c]; nRead _ nRead-1; EXIT } ; ENDCASE => scanBuf _ RefText.InlineAppendChar[scanBuf, c ] ; ENDLOOP ; RETURN[tokType~tokId, tokVal~Atom.MakeAtomFromRefText[scanBuf], charsRead~nRead] ; EXITS endOfFile => RETURN[tokType~tokEOF, charsRead~nRead] ; END END ; -- GetRussellToken END . ,RussellScannerImpl.mesa This module is a scanner for Russell 84. Last Edited by: Demers, March 5, 1984 4:34:50 pm PST Consume leading whitespace / comments to lookahead character. Switch based on first nonwhite character of token Default otherwise unrecognized tokens to operator identifiers. Κ‘˜head1™Ibodyšœ(™(L™4unitšΟk ˜ Icodešœœ ˜Nš œœœJœ œ˜xNšœœ˜Nšœœ˜ Nšœœ˜(—šΟnœ ˜!Nšœœ˜Nšœ˜š˜š˜N˜ N˜—šžœœœœ ˜Ašœ˜šœ˜N˜Nšœ˜N˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ˜Nšœ ˜—NšœΟc˜——šžœœ œœ œœœœœœ œ˜‰šœ˜Mšœœ˜Nšœœ˜ Nšœ œ˜Nšœ œ ˜Nšœ œ˜Nšœ œœ ˜š˜šœ=™=šœœ˜'Nšœœœ ˜$—šœ˜Nšœœœ ˜$—Nšœ˜—™1šœ˜ šœ œ˜!N˜Nšœ˜šœ9˜9Nšœœ-˜1—Nšœ˜šœ˜Nšœ)˜-—šœ˜Nšœœ%˜0—Nšœ,˜,NšœC˜INšœ˜—šœ˜N˜Nšœ˜šœ9˜9Nšœœ-˜1—Nšœ˜šœ˜Nšœ)˜-—šœ ˜šœ%˜%NšœJ˜P—šœ ˜ NšœK˜Q—šœ ˜ NšœM˜S—šœ˜ Nšœ%˜+——Nšœ˜—˜šœœ˜šœ˜ šœ˜˜N˜Nšœ˜Nšœ,˜2N˜—šœ˜ Nšœ˜——Nš˜——Nšœ)˜/N˜—˜šœœ˜šœ˜ šœ˜˜N˜Nšœ˜Nšœ,˜2N˜—šœ˜ Nšœ˜——Nšœ˜——N˜—˜šœœ˜šœ˜ šœ˜˜N˜Nšœ˜Nšœ)˜/N˜—šœ˜ Nšœ˜——Nšœ˜——N˜—˜šœœ˜šœ˜ šœ˜˜N˜Nšœ˜Nšœ,˜2N˜—šœ˜ Nšœ˜——Nšœ˜——N˜—˜Nšœ&˜,—˜Nšœ'˜-—˜Nšœ&˜,—˜Nšœ%˜+—˜Nšœ)˜/—˜Nšœ*˜0—˜Nšœ'˜-—˜Nšœ'˜-—˜Nšœ%˜+—˜Nšœ%˜+—˜Nšœ*˜0—˜Nšœ*˜0—˜Nšœ&˜,—˜Nšœ&˜,—˜Nšœ-˜3—šœœ˜ Nšœ%˜+—šœ˜ Nšœ˜———™>N˜Nšœ0˜0š˜Nšœœœ˜.N˜šœ˜ šœœœœœœ œ œUœœ˜–N˜N˜Nš˜N˜—šœ˜ Nšœ1˜1——Nš ˜ —NšœL˜R—š˜Nšœ œ#˜6—Nš˜—MšœŸ˜——Nšœ˜———J˜—…—|I