4Ic@sddkZddkTddkZyDddklZddklZddklZddk l Z Wne j onXde fdYZ d efd YZd eeeifd YZd ZdeeeifdYZdeeeifdYZdeeeifdYZdeeeifdYZdeeeifdYZdeeeifdYZdeeeifdYZ dee!fdYZ"de"e#ei#fdYZ$d e"e%ei%fd!YZ&d"e"e'ei'fd#YZ(d$ee)ei)fd%YZ*d&e"ei+fd'YZ+d(ee,ei,fd)YZ-d*efd+YZ.d,e/fd-YZ0d.Z1d/Z2e3d0jo e1ndS(1iN(t*(tCanvas(tTk(tFont(tin_idlet DrtTokenscBsVeZdZdZdZdZdZeeegZei eZ ei egeZ RS(tDRSt+tPROt[t]( t__name__t __module__RtDRS_CONCtPRONOUNt OPEN_BRACKETt CLOSE_BRACKETtPUNCTtTokenstSYMBOLStTOKENS(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs t AbstractDrscBseZdZdZdZdZdZdZdZe dZ dZ e e Z e d Zd Zed Zd Zd ZdZdZRS(si This is the base abstract abstract DRT Expression from which every DRT Expression extends. cCs t||S(N(tDrtApplicationExpression(tselftother((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytapplyto+scCs t|S(N(tDrtNegatedExpression(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__neg__.scCs tdS(N(tNotImplementedError(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__and__1scCs$t|tptt||S(N(t isinstanceRtAssertionErrortDrtOrExpression(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__or__4scCs$t|tptt||S(N(RRRtDrtImpExpression(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__gt__8scCs$t|tptt||S(N(RRRtDrtIffExpression(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__lt__<scCsKt|tpt|ii}|ii}|i||S(sPass the expression (self <-> other) to the theorem prover. If the prover says it is valid, then the self and other are equal.(RRRtsimplifyttoFolt tp_equals(RRtprovertf1tf2((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR(@scCstd|iidS(Ns#'%s' object has no attribute 'type'(tAttributeErrort __class__R (R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt _get_typeIscCs tdS(N(R(Rt signature((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt typecheckNscCs t||S(N(tConcatenationDRS(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__add__QscCs tdS(s Return the set of discourse referents in this DRS. @param recursive: C{boolean} Also find discourse referents in subterms? @return: C{list} of C{Variable}s N(R(Rt recursive((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytget_refsTscCsLt|to<t|ito)|iiitijot|it S(s Is self of the form "PRO(x)"? ( RRtfunctiontDrtAbstractVariableExpressiontvariabletnameRRtargumenttDrtIndividualVariableExpression(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytis_pronoun_function\scCs t||S(N(tDrtEqualityExpression(Rtfirsttsecond((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_EqualityExpressioncscCs t|S(N(tDrtVariableExpression(RR7((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_VariableExpressionfscCst|idS(N(t DrsDrawertdraw(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRCis(R R t__doc__RRRR!R#R%tNoneR(R.tpropertyttypeR0R2tFalseR4R;R?RARC(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR&s"              RcBsweZdZdZedZdZedZedZ dZ dZ dZ d Z eid ZRS( s%A Discourse Representation Structure.cCs||_||_dS(s @param refs: C{list} of C{DrtIndividualVariableExpression} for the discourse referents @param conds: C{list} of C{Expression} for the conditions N(trefstconds(RRIRJ((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__init__os c Cs}y|ii|}|p|Sn[t|i| |ig|i|dg}|iD]}||i||tqX~SWntj oxt|i|i @D]}t |}t |} |ii|}t|i| |g|i|dg} |iD]}| |i|| tq ~ }qWt|ig} |iD]}| |i|||qN~ SnXdS(s_Replace all instances of variable v with expression E in self, where v is free in self.iN( RItindexRR7RJtreplacetTruet ValueErrortsettfreetunique_variableR@( RR7t expressiont replace_boundtit_[1]tcondtreftnewvartnewvarext_[2]t_[3]((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRMxs$&8  #3 cCsMttig}|iD]}||iq~t}|t|iS(s@see: Expression.variables()(treducetoperatortor_RJt variablesRPRI(RRVtct conds_vars((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR`s 3cCsPttig}|iD]}||i|q~t}|t|iS(s@see: Expression.free()(R]R^R_RJRQRPRI(Rt indvar_onlyRVRat conds_free((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRQs 6cCs]|oKttig}|iD]}||itq~g}|i|Sn|iSdS(s#@see: AbstractExpression.get_refs()N(R]R^taddRJR4RNRI(RR3RVRat cond_refs((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4s  3cCs;t|g}|i|iD]}|||q~|S(s@see: Expression.visit()(R]RIRJ(RR5t combinatortdefaultRVte((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytvisitscCs4t|ig}|iD]}||iq~S(N(RRIRJR&(RRVRW((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR&scCs|iptdnttg}|iD]}||iq.~}x-|idddD]}t||}qdW|S(Ns-Cannot convert DRS with no conditions to FOL.i(RJt ExceptionR]t AndExpressionR'RItExistsExpression(RRVRataccumRX((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR's 3cCst|tot|it|ijod|}xGt|i|iD]0\}}|i|}|i||t}qKW|i|ijSqnt S(s}Defines equality modulo alphabetic variance. If we are comparing \x.M and \y.N, then check equality of M and N[x/y].( RRtlenRItzipRARMRNRJRH(RRtconverted_othertr1tr2tvarex((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt__eq__s c Cs|tijo|ii|Snlddig}|iD]}|t|q>~dig}|iD]}||i|qn~fSdS(Ns ([%s],[%s])t,s, (RtPROVER9R'tstrtjoinRIRJ(RtsyntaxRVtrR[Ra((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRxs3(R R RDRKRHRMR`RNRQR4RjR&R'RuRtNLTKRx(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRms       cCsht|iot|SnGt|iot|Sn)t|iot|Sn t|SdS(s This is a factory method that instantiates and returns a subtype of C{DrtAbstractVariableExpression} appropriate for the given variable. N(t is_indvarR8R:t is_funcvartDrtFunctionVariableExpressiont is_eventvartDrtEventVariableExpressiontDrtConstantExpression(R7((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR@sR6cBseZdZedZRS(cCs|S(N((R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR'scCsgS(s#@see: AbstractExpression.get_refs()((RR3((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4s(R R R'RHR4(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR6s R:cBseZRS((R R (((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR:sRcBseZRS((R R (((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRsRcBseZRS((R R (((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRsRcBseZRS((R R (((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRsRcBseZdZRS(cCst|iiS(N(tNegatedExpressionttermR'(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR's(R R R'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRstDrtLambdaExpressioncBseZdZdZRS(cCs+|i||ii|it|tS(sRename all occurrences of the variable introduced by this variable binder in the expression to @C{newvar}. @param newvar: C{Variable}, for the new variable (R-RRMR7R@RN(RRY((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt alpha_convertscCst|i|iiS(N(tLambdaExpressionR7RR'(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR' s(R R RR'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs tDrtBooleanExpressioncBseZedZRS(cCs3|o$|iit|iitSngSdS(s#@see: AbstractExpression.get_refs()N(R=R4RNR>(RR3((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4 s$(R R RHR4(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR sR cBseZdZRS(cCst|ii|iiS(N(t OrExpressionR=R'R>(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR's(R R R'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR sR"cBseZdZRS(cCs|i}|i}d}|io7ttg}|iD]}||iq6~}n|ot||i}n |i}x-|idddD]}t ||}qW|S(Ni( R=R>RERJR]RlR't ImpExpressionRIt AllExpression(Rt first_drst second_drsRnRVRaRX((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR's   1 (R R R'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR"sR$cBseZdZRS(cCst|ii|iiS(N(t IffExpressionR=R'R>(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR'.s(R R R'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR$,sR<cBseZdZedZRS(cCst|ii|iiS(N(tEqualityExpressionR=R'R>(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR'3scCs3|o$|iit|iitSngSdS(s#@see: AbstractExpression.get_refs()N(R=R4RNR>(RR3((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR46s$(R R R'RHR4(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR<1s R1cBsPeZdZedZdZedZeidZ dZ dZ RS(sDRS of the form '(DRS + DRS)'cCs|i}|i}t|tomt|to]|t|itt|it@jo.|i||t}|i||t}nCt|toI||ijo9|o.|i|||}|i|||}qnt|toI||ijo9|o.|i|||}|i|||}qnxct|it|i @D]B}t t |}|i||t}|i||t}qaW|i|||}|i|||}|i ||S(s_Replace all instances of variable v with expression E in self, where v is free in self.( R=R>RRRPR4RNRMRIRQR@RRR-(RR7RSRTR=R>RXtv((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRM?s,   /   cCs|ii}|ii}t|tot|toxWt|itt|it@D]-}tt |}|i ||t}qgWt|i |i |i |i Sn|i ||SdS(N(R=R&R>RRRPR4RNR@RRRMRIRJR-(RR=R>RXRY((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR&cs )%cCs |ii||ii|S(s#@see: AbstractExpression.get_refs()(R=R4R>(RR3((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4rscCstiS(N(RR (RRz((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytgetOpvscCst|to|i}|i}t|t|joq|}xAt||D]0\}}|i|}|i||t}qWW|i|ijo|i |i jSqnt S(s}Defines equality modulo alphabetic variance. If we are comparing \x.M and \y.N, then check equality of M and N[x/y].( RR1R4RoRpRARMRNR=R>RH(RRt self_refst other_refsRqRrRsRt((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRuys   cCst|ii|iiS(N(RlR=R'R>(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR's( R R RDRHRMR&R4RR|RRuR'(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR1=s $   RcBseZdZedZRS(cCst|ii|iiS(N(tApplicationExpressionR5R'R9(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR'scCs3|o$|iit|iitSngSdS(s#@see: AbstractExpression.get_refs()N(R5R4RNR9(RR3((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4s$(R R R'RHR4(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs RBcBseZdZdZdZeedZdZeedZ dZ dZ dZ d d d Z d Zd Zd ZdZdZdZdZRS(ii ic Cs#ti|_d }|pt}|idtdddd}|ot|dddd}||_||_ |i ||i |i \}}t ||i d }||i } t|d|d| }nt|dd dd }|i||_n||_ ||_||_d S( s @param drs: C{AbstractDrs}, The DRS to be drawn @param size_canvas: C{boolean}, True if the canvas size should be the exact size of the DRS @param canvas: C{Canvas} The canvas on which to draw the DRS. If none is given, create a new canvas. tDRTtfamilyt helveticatsizei twidthitheightidi,N(RR|RzRERttitleRRtfonttcanvast_visitt OUTERSPACEtTOPSPACEtmaxtpacktdrstmaster( RRt size_canvasRRRtrighttbottomRR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRKs(     !     cCs|iiidS(s Get the height of a line of textt linespace(RRtmetrics(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt_get_text_heightscCs\|i|i|i|||iot o|iin|i|i||SdS(s Draw the DRSN(t_handleRt _draw_commandRRtmainloopR(Rtxty((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRCscCs|i||i||S(s) Return the bottom-rightmost point without actually drawing the item @param expression: the item to visit @param x: the top of the current drawing area @param y: the left side of the current drawing area @return: the bottom-rightmost point (Rt_visit_command(RRSRR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs c Cst|to/|ii||ddd|iid|nnt|to]|\}}|ii||||||i|id}|ii ||||n|i |||S(s  Draw the given item at the given location @param item: the item to draw @param x: the top of the current drawing area @param y: the left side of the current drawing area @return: the bottom-rightmost point tanchortnwRttexti( RRxRt create_textRttupletcreate_rectangleRtBUFFERt create_lineR(RtitemRRRRt horiz_line_y((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs / cCsWt|to+||iii|||ifSnt|to|SndS(s# Return the bottom-rightmost point without actually drawing the item @param item: the item to visit @param x: the top of the current drawing area @param y: the left side of the current drawing area @return: the bottom-rightmost point N(RRxRRtmeasureRR(RRRR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs +icCsn||ijoBy(|i|}|i|}||fSWqRtj oqRXnt|to |i}nt|to |i}nt|t o |i }nt|t o |i }njt|t o |i}nMt|to |i}n0t|tio |i}nt|ii|||||\}}|||_|||_||fS(s1 @param expression: the expression to handle @param command: the function to apply, either _draw_command or _visit_command @param x: the top of the current drawing area @param y: the left side of the current drawing area @return: the bottom-rightmost point (Rt_drawing_widtht_drawing_heightR,RR6t_handle_VariableExpressionRt _handle_DRSRt_handle_NegatedExpressionRt_handle_LambdaExpressiontBinaryExpressiont_handle_BinaryExpressionRt_handle_ApplicationExpressiontRAtPossibleAntecedentsRkR-R (RRStcommandRRRRtfactory((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs4            cCs||i|i||S(N(RxRz(RRSRRR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR%scCs|iti|i||d}|i|i|||\}}|ti|i||i||||i||fS(Ni(RRtNOTRzRRt_get_centered_topR(RRSRRRRR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR(s#!3c Cs ||i}||i}|io7dig}|iD]}|t|q8~} nd} || ||\} }||id7}|ioRxf|iD]@} |i| |||\} }t| | } ||i7}qWn||i|i7}| |i7} || |f||S(Nt s i(RRIRyRxRJRRR( RRSRRRtleftRRVRXRIt max_rightRWR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR4s    7   c Cs|i\}}t|tp|i}|ig}n|i|||d}t|gg}|D] } ||i| ||dqh~} | |} |i|| |i} |i |||| d} |i|| |i }|t i | |d} xt |D]x\}} |i|| | i}|i | || |d} |dt|jo!|t id| |d} qqW|t i| |d} | | fS(NiiR(tuncurryRR6R5R9RRRRRRRtOPENt enumerateRotCOMMAtCLOSE(RRSRRRR5targstfunction_bottomRVtargt max_bottomt line_heighttfunction_drawing_topRtcentred_string_topRUtarg_drawing_top((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRMs& A  %cCsti|it|iti|i}|i|||d}|i|i|||\}}||||i ||||i ||fS(Ni( RtLAMBDARzRxR7tDOTRRRRR(RRSRRRR`RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRps +!)c CsE|i|iddd}|i|iddd}t||}|i|||i}|ti||d} |ii}|i |i|| |i|||\} } |d|i |i | |d} |ii}|i |i|| |i|||\} } |ti | |d} | t| | fS(Niis %s ( RR=R>RRRRRRRRRzR( RRSRRRt first_heightt second_heightRRRt first_bottomt second_bottom((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR}s 0& 0cCs|||dS(sGet the y-coordinate of the point that a figure should start at if its height is 'item_height' and it needs to be centered in an area that starts at 'top' and is 'full_height' tall.i((Rttopt full_heightt item_height((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs(R R RRRRNRERKRRCRRRRRRRRRRR(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRBs""   ,   # t DrtParsercBszeZdZdZdZdZdZdZdZdZ dZ d Z d Z d Z d ZRS( s$A lambda calculus expression parser.cCsti|dS(N(t LogicParserRK(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRKscCstiS(s#This method exists to be overridden(RR(R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytget_all_symbolsscCs |tijS(N(RR(Rttok((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt isvariablescCs|tijo|iSn|tijo|i|Sn|tijo8|idtijo|iSq|i |Sn_|i ti jo'|i |iti|iSn"|i |o|i|SndS(shThis method is intended to be overridden for logics that use different operators or expressionsiN(RRthandle_negationRt handle_lambdaRttokenRt handle_DRSt handle_opentupperRt assertTokenRthandle_variable(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pythandlescCs t|S(N(R(RRS((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_NegatedExpressionscCs[|i|itig}x^|idtijoD|idtijo|iq"|it|iq"W|i|idtijo|in|i|itig}xX|idtijo>|idtijo|iq|i|iqW|i|i|iti t ||S(Ni( RRRRRRtappendtVariabletparse_ExpressionRR(RRIRJ((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs$  cCs t||S(slThis method serves as a hook for other logic parsers that have different equality expression classes(R<(RR=R>((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyR?scCsh|tijotSnM|tijotSn5|tijotSn|tijotSndSdS(sbThis method serves as a hook for other logic parsers that have different boolean operatorsN( RR R1tORR tIMPR"tIFFR$RE(RR((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytget_BooleanExpression_factoryscCs |||S(N((RRR=R>((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_BooleanExpressionscCs t||S(N(R(RR5R9((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_ApplicationExpressionscCstt|S(N(R@R(RR8((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRAscCs t||S(N(R(RR`R((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytmake_LambdaExpressions(R R RDRKRRRRRR?RRRRAR(((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyRs           cCsHdddGHt}|idGH|idGH|idGH|idGH|idGH|id GH|id GH|id GH|id GHdd dGH|idiGHdddGH|id}|GH|itd}|GH||jGHdddGH|idiGH|idiGH|idiGHdS(Nt=is TEST PARSEs([x,y],[sees(x,y)])s([x],[man(x), walks(x)])s\x.\y.([],[sees(x,y)])s\x.([],[walks(x)])(john)s$(([x],[walks(x)]) + ([y],[runs(y)]))s#(([],[walks(x)]) -> ([],[runs(x)]))s([x],[PRO(x), sees(John,x)])s ([x],[man(x), -([],[walks(x)])])s*([],[(([x],[man(x)]) -> ([],[walks(x)]))])s Test toFol()s4Test alpha conversion and lambda expression equalitys\x.([],[P(x)])tzsTest resolve_anaphora()s,([x,y,z],[dog(x), cat(y), walks(z), PRO(z)])s3([],[(([x],[dog(x)]) -> ([y],[walks(y), PRO(y)]))])s(([x,y],[]) + ([],[PRO(x)]))s====================s====================s====================s====================s====================s====================s====================s====================(RtparseR'RRtresolve_anaphora(tparserte1te2((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pytdemos.      c CsXddddddddd d d g }x*|D]"}ti|}|iq.WdS( NRs([],[])s([x],[])s([x],[man(x)])s([x,y],[sees(x,y)])s([x],[man(x), walks(x)])s\x.([],[man(x), walks(x)])s\x y.([],[sees(x,y)])s)([],[(([],[walks(x)]) + ([],[runs(x)]))])s ([x],[man(x), -([],[walks(x)])])s*([],[(([x],[man(x)]) -> ([],[walks(x)]))])(RRRC(t expressionsRitd((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyt test_draws t__main__(4R^tlogictdrt_resolve_anaphoraRtTkinterRRttkFontRtnltkRt ImportErrorRRtobjectRt ExpressionRR@tAbstractVariableExpressionR6tIndividualVariableExpressionR:tFunctionVariableExpressionRtEventVariableExpressionRtConstantExpressionRRRRRtBooleanExpressionRRR RR"RR$RR<R1RRRBRRRRR (((s"/p/zhu/06/nlp/nltk/nltk/sem/drt.pyssb   G`       N  a