Add lastError function

M2/Macaulay2/d/actors5.d

@@ -1813,6 +1813,9 @@ export StandardE := Expr(StandardS);
 export topLevelMode := Expr(StandardS);
 topLevelModeS := dummySymbol;
 
+threadLocal lastError := nullE;
+lastErrorS := dummySymbol;
+
 initialRandomSeed := zeroZZ;
 initialRandomHeight := toInteger(10);
 
@@ -1847,7 +1850,8 @@ syms := SymbolSequence(
      (  handleInterruptsS = setupvar("handleInterrupts",toExpr(handleInterrupts));  handleInterruptsS  ),
      (  printWidthS = setupvar("printWidth",toExpr(printWidth));  printWidthS  ),
      (  notifyS = setupvar("notify",toExpr(notify));  notifyS  ),
-     (  topLevelModeS = setupvar("topLevelMode",topLevelMode); topLevelModeS  )
+     (  topLevelModeS = setupvar("topLevelMode",topLevelMode); topLevelModeS  ),
+     (  lastErrorS = setupvarThread("lastError", lastError); lastErrorS )
      );
 
 export setDebuggingMode(b:bool):void := (
@@ -1886,6 +1890,17 @@ export sethandleInterrupts(b:bool):void := (
      handleInterruptsSetup(b);
      setGlobalVariable(handleInterruptsS,toExpr(b));
      );
+setLastError(position:Position, message:string):void := (
+    if !(
+	message == returnMessage   ||
+	message == continueMessage || message == continueMessageWithArg ||
+	message == stepMessage     || message == stepMessageWithArg     ||
+	message == breakMessage)
+    then (
+	lastError = seq(locate(position), toExpr(message));
+	setGlobalVariable(lastErrorS, lastError)));
+setLastErrorpointer = setLastError;
+
 threadLocal resetvars := (
      -- These are the thread local variables that got re-initialized in tokens.d:
      -- Actually, this is no good!  If the user assigns to one of these variables, the "top level" version
@@ -1909,6 +1924,21 @@ store(e:Expr):Expr := (			    -- called with (symbol,newvalue)
 	  else when s.1
 	  is Nothing do (
 	       if sym === debuggerHookS then (debuggerHook = s.1; e)
+	       else if sym === lastErrorS then (lastError = s.1; e)
+	       else buildErrorPacket(msg))
+	  is a:Sequence do (
+	       if sym === lastErrorS then (
+		   if length(a) == 2 then (
+		       when a.0
+		       is p:List
+		       do (
+			   if p.Class == filePositionClass then (
+			       when a.1
+			       is msg:stringCell do (lastError = s.1; e)
+			       else WrongArgString(2))
+			   else WrongArg(1, "a file position"))
+		       else WrongArg(1, "a file position"))
+		   else WrongNumArgs(2))
 	       else buildErrorPacket(msg))
 	  is b:Boolean do (
 	       n := b.v;

M2/Macaulay2/d/binding.d

@@ -415,10 +415,12 @@ export makeSymbol(t:Token):Symbol := (
 export makeErrorTree(e:ParseTree,message:string):void := (
      HadError = true;
      printErrorMessage(treePosition(e),message);
+     setLastErrorpointer(treePosition(e), message);
      );
 export makeErrorTree(e:Token,message:string):void := (
      HadError = true;
      printErrorMessage(e,message);
+     setLastErrorpointer(e.position, message);
      );
 makeSymbol(e:ParseTree,dictionary:Dictionary):void := (
      when e
@@ -472,14 +474,8 @@ lookup(t:Token,forcedef:bool,thread:bool):void := (
      	  is entry:Symbol do (
 	       t.entry = entry;
 	       if entry.position == tempPosition then entry.position = t.position;
-	       if entry.flagLookup then (
-		    printErrorMessage(t,"flagged symbol encountered");
-		    HadError=true;
-		    );
-	       if thread && !entry.thread then (
-		    printErrorMessage(t,"symbol already present, but not thread local");
-		    HadError=true;
-		    );
+	       if entry.flagLookup then makeErrorTree(t,"flagged symbol encountered");
+	       if thread && !entry.thread then makeErrorTree(t,"symbol already present, but not thread local");
 	       )
      	  else (
 	       if forcedef
@@ -495,9 +491,7 @@ lookup(t:Token,forcedef:bool,thread:bool):void := (
 		    t.dictionary = globalDictionary; -- undefined variables are defined as global
 		    t.entry = makeSymbol(t.word,t.position,globalDictionary,thread,locallyCreated);
 		    )
-	       else (
-	       	    printErrorMessage(t,"undefined symbol " + t.word.name);
-	       	    HadError=true;))));
+	       else makeErrorTree(t,"undefined symbol " + t.word.name))));
 lookup(t:Token):void := lookup(t,true,false);
 lookuponly(t:Token):void := lookup(t,false,false);
 -----------------------------------------------------------------------------

M2/Macaulay2/d/evaluate.d

@@ -1343,8 +1343,9 @@ steppingFurther(c:Code):bool := steppingFlag && (
 
 handleError(c:Code,e:Expr):Expr := (
      when e is err:Error do (
-	  if SuppressErrors then return e;
-	  if err.message == returnMessage
+	  p := codePosition(c);
+	  if SuppressErrors
+	  || err.message == returnMessage
 	  || err.message == continueMessage || err.message == continueMessageWithArg
 	  || err.message == stepMessage || err.message == stepMessageWithArg
 	  || err.message == breakMessage
@@ -1353,10 +1354,9 @@ handleError(c:Code,e:Expr):Expr := (
 	  then (
 	       -- an error message that is really being used to transfer control must be passed up the line
 	       -- the position is plugged in just in case it's unhandled
-	       if err.position == dummyPosition then err.position = codePosition(c);
+	       if err.position == dummyPosition then err.position = p;
 	       return e;
 	       );
-	  p := codePosition(c);
 	  clearAllFlags();
 	  clearAlarm();
 	  if p.loadDepth >= errorDepth && !err.position === p then (
@@ -1585,7 +1585,14 @@ export evalraw(c:Code):Expr := (
 	       	    tmp)
 	       else AngleBarList(r)
 	       ));
-     when e is Error do handleError(c,e) else e);
+     when e is Error
+     do (
+	 f := handleError(c,e);
+	 when f is err:Error
+	 do setLastErrorpointer(err.position, err.message)
+	 else nothing;
+	 f)
+     else e);
 
 export evalexcept(c:Code):Expr := (
      -- printErrorMessage(codePosition(c),"--evaluating: "+present(tostring(c)));

M2/Macaulay2/d/lex.d

@@ -82,6 +82,20 @@ export install(name:string,word:Word):Word := (
      foreach ch in name do node = install(node,int(ch));     
      node.word = word;
      word);
+
+-- setLastError defined in actors5.d
+dummysetLastError(position:Position, message:string):void := nothing;
+export setLastErrorpointer := dummysetLastError;
+
+makeLexError(position:Position, message:string):void := (
+    printErrorMessage(position, message);
+    setLastErrorpointer(position, message);
+    empty(tokenbuf));
+
+newPosition(file:PosFile, line:ushort, column:ushort):Position := Position(
+    --             [ beginning ] [      endpoint       ] [   focus   ]
+    file.filename, line, column, file.line, file.column, line, column, loadDepth);
+
 recognize(file:PosFile):(null or Word) := (
      i := 0;
      state := baseLexNode;
@@ -98,7 +112,7 @@ recognize(file:PosFile):(null or Word) := (
      is null do (
 	  p := position(file);
 	  getc(file);
-	  printErrorMessage(p,"invalid character" );
+	  makeLexError(p, "invalid character");
 	  (null or Word)(NULL))
      is word:Word do ( 
 	  for length(word.name) do getc(file); 
@@ -117,13 +131,14 @@ getstringslashes(o:PosFile):(null or Word) := (		    -- /// ... ///
 	  ch := getc(o);
 	  if ch == ERROR then (
 	       if !test(interruptedFlag)
-	       then printErrorMessage(o.filename,line,column,"ERROR in string /// ... /// beginning here: " + o.file.errorMessage);
-	       empty(tokenbuf);
+	       then makeLexError(newPosition(o, line, column),
+		   "ERROR in string /// ... /// beginning here: "
+		   + o.file.errorMessage);
 	       return NULL;
 	       );
 	  if ch == EOF then (
-	       printErrorMessage(o.filename,line,column,"EOF in string /// ... /// beginning here");
-	       empty(tokenbuf);
+	       makeLexError(newPosition(o, line, column),
+		   "EOF in string /// ... /// beginning here");
 	       return NULL;
 	       );
 	  -- this allows us to get 3,4,5,... slashes within the string by typing 4,6,8,... slashes
@@ -168,17 +183,16 @@ getstring(o:PosFile):(null or Word) := (
 	  ch := getc(o);
 	  if ch == ERROR then (
 	       if !test(interruptedFlag)
-	       then printErrorMessage(o.filename,line,column,
-		    (if o.file.eof 
-			 then "reading beyond EOF in string beginning here: "
-			 else "ERROR in string beginning here: ")
-		    + o.file.errorMessage);
-	       empty(tokenbuf);
+	       then makeLexError(newPosition(o, line, column),
+		   (if o.file.eof
+		       then "reading beyond EOF in string beginning here: "
+		       else "ERROR in string beginning here: ")
+		   + o.file.errorMessage);
 	       return NULL;
 	       );
 	  if ch == EOF then (
-	       printErrorMessage(o.filename,line,column,"EOF in string beginning here");
-	       empty(tokenbuf);
+	       makeLexError(newPosition(o, line, column),
+		   "EOF in string beginning here");
 	       return NULL;
 	       );
      	  tokenbuf << char(ch);
@@ -187,9 +201,9 @@ getstring(o:PosFile):(null or Word) := (
 		    hexcoming = hexcoming - 1;
 		    )
 	       else (
-		    printErrorMessage(o.filename,line,column,"expected " +
-			tostring(hexcoming) + " more hex digit(s)");
-		    empty(tokenbuf);
+		    makeLexError(newPosition(o, line, column),
+			"expected " + tostring(hexcoming) +
+			" more hex digit(s)");
 		    while true do (ch2 := getc(o); if ch2 == EOF || ch2 == ERROR || ch2 == int('\n') then return NULL;);
 		    )
 	       )
@@ -211,8 +225,8 @@ getstring(o:PosFile):(null or Word) := (
 	       || int('0') <= ch && ch < int('8')
 	       then escaped = false
 	       else (
-		    empty(tokenbuf);
-		    printErrorMessage(o.filename,line,column,"unknown escape sequence: \\" + char(ch));
+		    makeLexError(newPosition(o, line, column),
+			"unknown escape sequence: \\" + char(ch));
 		    while true do (ch2 := getc(o); if ch2 == EOF || ch2 == ERROR || ch2 == int('\n') then return NULL;);
 		    );
 	       )
@@ -285,23 +299,20 @@ export errorToken := Token(Word("-*error token*-",TCnone,hash_t(0),newParseinfo(
      globalDictionary,			    -- should replace this by dummyDictionary, I think
      dummySymbol,false);
 
-newPosition(file:PosFile, line:ushort, column:ushort):Position := Position(
-    --             [ beginning ] [      endpoint       ] [   focus   ]
-    file.filename, line, column, file.line, file.column, line, column, loadDepth);
-
 gettoken1(file:PosFile,sawNewline:bool):Token := (
      -- warning : tokenbuf is static
      while true do (
 	  rc := skipwhite(file);
 	  if rc == ERROR then return errorToken;
 	  if rc == EOF  then (
-	       printErrorMessage(file.filename,swline,swcolumn,"EOF in block comment -* ... *- beginning here");
-	       -- empty(tokenbuf);
+	       makeLexError(newPosition(file, swline, swcolumn),
+		   "EOF in block comment -* ... *- beginning here");
 	       -- while true do (ch2 := getc(file); if ch2 == EOF || ch2 == ERROR || ch2 == int('\n') then break;);
      	       return errorToken;
 	       );
 	  if rc == DEPRECATED then (
-	       printErrorMessage(file.filename,swline,swcolumn,"encountered disabled block comment syntax {* ... *} beginning here");
+	       makeLexError(newPosition(file, swline, swcolumn),
+		   "encountered disabled block comment syntax {* ... *} beginning here");
      	       return errorToken;
 	       );
 	  line := file.line;
@@ -371,8 +382,8 @@ gettoken1(file:PosFile,sawNewline:bool):Token := (
 			      tokenbuf << char(getc(file));
 			      while isdigit(peek(file)) do tokenbuf << char(getc(file)))
 			 else (
-			      printErrorMessage(position(file),"precision missing in floating point constant");
-			      empty(tokenbuf);
+			      makeLexError(position(file),
+				  "precision missing in floating point constant");
 			      return errorToken;
 			      )
 			 );
@@ -387,8 +398,8 @@ gettoken1(file:PosFile,sawNewline:bool):Token := (
 			      while isdigit(peek(file)) do tokenbuf << char(getc(file));
 			      )
 			 else (
-			      printErrorMessage(position(file),"exponent missing in floating point constant");
-			      empty(tokenbuf);
+			      makeLexError(position(file),
+				  "exponent missing in floating point constant");
 			      return errorToken;
 			      )
 			 );
@@ -419,10 +430,7 @@ gettoken1(file:PosFile,sawNewline:bool):Token := (
 		   newPosition(file, line, column), globalDictionary, dummySymbol, sawNewline))
 	  else (
 	       when recognize(file)
-	       is null do (
-		    empty(tokenbuf);
-		    return errorToken
-		    )
+	       is null do return errorToken
 	       is word:Word do return Token(word,
 		   newPosition(file, line, column), globalDictionary, dummySymbol, sawNewline))
 	       )