Raise error if eager float literal conversion fails (fixes #1105)

src/intrprtr.c

@@ -1790,19 +1790,24 @@ void IntrLongIntExpr(Obj string)
 
 static Obj CONVERT_FLOAT_LITERAL_EAGER;
 
-static Obj ConvertFloatLiteralEager(Obj str) {
-  Char *chars = (Char *)CHARS_STRING(str);
-  UInt len = GET_LEN_STRING(str);
-  Char mark = '\0';
-  if (chars[len-1] == '_') {
-    SET_LEN_STRING(str, len-1);
-    chars[len-1] = '\0';
-  } else if (chars[len-2] == '_') {
-    mark = chars[len-1];
-    SET_LEN_STRING(str, len-2);
-    chars[len-2] = '\0';
-  }
-  return CALL_2ARGS(CONVERT_FLOAT_LITERAL_EAGER, str, ObjsChar[(UInt)mark]);
+static Obj ConvertFloatLiteralEager(Obj str)
+{
+    Char * chars = (Char *)CHARS_STRING(str);
+    UInt   len = GET_LEN_STRING(str);
+    Char   mark = '\0';
+    if (chars[len - 1] == '_') {
+        SET_LEN_STRING(str, len - 1);
+        chars[len - 1] = '\0';
+    }
+    else if (chars[len - 2] == '_') {
+        mark = chars[len - 1];
+        SET_LEN_STRING(str, len - 2);
+        chars[len - 2] = '\0';
+    }
+    Obj res = CALL_2ARGS(CONVERT_FLOAT_LITERAL_EAGER, str, ObjsChar[(UInt)mark]);
+    if (res == Fail)
+        ErrorQuit("failed to convert float literal", 0, 0);
+    return res;
 }
 
 void            IntrFloatExpr (

src/read.c

@@ -778,14 +778,16 @@ void ReadCallVarAss(TypSymbolSet follow, Char mode)
         // deal with references
         if (mode == 'r' || (mode == 'x' && STATE(Symbol) != S_ASSIGN)) {
             Obj val = ValAutoGVar(ref.var);
-            if (val == True)
-                IntrTrueExpr();
-            else if (val == False)
-                IntrFalseExpr();
-            else if (IS_INTOBJ(val))
-                IntrIntObjExpr(val);
-            else
-                SyntaxError("Invalid constant variable");
+            TRY_READ {
+                if (val == True)
+                    IntrTrueExpr();
+                else if (val == False)
+                    IntrFalseExpr();
+                else if (IS_INTOBJ(val))
+                    IntrIntObjExpr(val);
+                else
+                    SyntaxError("Invalid constant variable");
+            }
             return;
         }
     }
@@ -976,7 +978,7 @@ void ReadLongNumber(
          case S_INT:
            appendToString(string, STATE(Value));
            Match(S_INT, "integer", follow);
-           IntrLongIntExpr(string);
+           TRY_READ { IntrLongIntExpr(string); }
            done = 1;
            break;
 
@@ -1001,7 +1003,7 @@ void ReadLongNumber(
          case S_FLOAT:
            appendToString(string, STATE(Value));
            Match(S_FLOAT, "float", follow);
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
            break;
 
@@ -1010,7 +1012,7 @@ void ReadLongNumber(
 
          default:
            appendToString(string, STATE(Value));
-           IntrLongIntExpr(string);
+           TRY_READ { IntrLongIntExpr(string); }
            done = 1;
          }
          break;
@@ -1036,7 +1038,7 @@ void ReadLongNumber(
          case S_FLOAT:
            appendToString(string, STATE(Value));
            Match(S_FLOAT, "float", follow);
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
            break;
 
@@ -1066,7 +1068,7 @@ void ReadLongNumber(
          case S_FLOAT:
            appendToString(string, STATE(Value));
            Match(S_FLOAT, "float", follow);
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
            break;
 
@@ -1076,7 +1078,7 @@ void ReadLongNumber(
 
          default:
            appendToString(string, STATE(Value));
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
          }
          break;
@@ -1102,7 +1104,7 @@ void ReadLongNumber(
          case S_FLOAT:
            appendToString(string, STATE(Value));
            Match(S_FLOAT, "float", follow);
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
            break;
 
@@ -1133,7 +1135,7 @@ void ReadLongNumber(
          case S_FLOAT:
            appendToString(string, STATE(Value));
            Match(S_FLOAT, "float", follow);
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
            break;
 
@@ -1142,7 +1144,7 @@ void ReadLongNumber(
 
          default:
            appendToString(string, STATE(Value));
-           IntrLongFloatExpr(string);
+           TRY_READ { IntrLongFloatExpr(string); }
            done = 1;
 
          }
@@ -1185,7 +1187,7 @@ void ReadString(
      SET_LEN_STRING(string, len);
      /* ensure trailing zero for interpretation as C-string */
      *(CHARS_STRING(string) + len) = 0;
-     IntrStringExpr( string );
+     TRY_READ { IntrStringExpr( string ); }
 }
 
 /****************************************************************************
@@ -2047,7 +2049,7 @@ void ReadQualifiedExpr (
     TypSymbolSet        follow,
     Char                mode )
 {
-  UInt access  = 0;
+  volatile UInt access  = 0;
   if (STATE(Symbol) == S_READWRITE) 
     {
       Match( S_READWRITE, "readwrite", follow | EXPRBEGIN );
@@ -2058,9 +2060,9 @@ void ReadQualifiedExpr (
       Match( S_READONLY, "readonly", follow | EXPRBEGIN );
       access = 1;
     }
-  IntrQualifiedExprBegin(access);
+  TRY_READ { IntrQualifiedExprBegin(access); }
   ReadExpr(follow,mode);
-  IntrQualifiedExprEnd();
+  TRY_READ { IntrQualifiedExprEnd(); }
 }
 
 

src/read.h

@@ -35,10 +35,16 @@
 **    }
 **
 **  Then, if the reader encounters an error, or if the interpretation of an
-**  expression or statement leads to an error, then 'ReadEvalError' is
-**  invoked which in turn calls 'longjmp' to return to right after the block
+**  expression or statement leads to an error, 'ReadEvalError' is invoked,
+**  which in turn calls 'longjmp' to return to right after the block
 **  following TRY_READ.
 **
+**  A second effect of 'TRY_READ' is that it prevents the execution of the
+**  code it wraps if 'STATE(NrError)' is non-zero, i.e. if any errors
+**  occurred. This is key for enabling graceful error recovery in the reader,
+**  and for this reason it is crucial that all calls from the reader into
+**  the interpreter are wrapped into 'TRY_READ' blocks.
+**
 **  Note that while you can in principle nest TRY_READ constructs, to do this
 **  correctly, you must backup ReadJmpError before TRY_READ, and restore it
 **  in a matching CATCH_READ_ERROR block.

tst/testinstall/float.tst

@@ -237,6 +237,27 @@ false
 gap> EqFloat(0.0,0.0/0.0);
 false
 
+#
+# float literals in the REPL
+#
+gap> 1.1;
+1.1
+gap> 1.1_;
+1.1
+gap> 1.x1;
+Syntax error: Badly formed number in stream:1
+1.x1;
+  ^
+gap> 1.1xx;
+Syntax error: Badly formed number in stream:1
+1.1xx;
+   ^
+
+# The following is potentially correct, *if* there is a conversion handler for
+# 'x' installed, which normally isn't the case.
+gap> 1.1x;
+Error, failed to convert float literal
+
 #
 # float literal expressions in functions
 #

tst/testinstall/longnumber.tst

@@ -180,7 +180,7 @@ int in stream:1
 .q;
 ^
 gap> .0n;
-fail
+Error, failed to convert float literal
 gap> .0q;
 Syntax error: Badly Formed Number: need at least one digit in the exponent in \
 stream:1