Abort not aborting

Question

I have a relatively simple bit of code that looks like the following:

---some code here---
If[statement, Abort[]];
---more code following---

However, while $Aborted appears as output, the evaluation of the rest of the cell does not abort, continuing execution of code beyond the If statement. How do I actually get the running cell to cease evaluating the rest of the cell?

Edit: It seems that one way to accomplish this is to wrap the entire cell in parenthesis, e.g., but this is a fairly ugly solution, especially with auto-formatting turned on (my cell has many lines of code, and the parenthesis are huuuuuge). Anyone have a more elegant solution?

(
---some code here---
If[statement, Abort[]];
---more code following---
)

Answer 1

This question has been asked before on stack overflow. However we will summerize some of the answers given there on our new Mathematica site.

Wrap In Compound Expression

One suggestion by Michael Pilat, given there was to wrap your lines in CompoundExpression, e.g.

(
   Print@Range[5];
   Abort[];
   Print@Range[5];
)

During evaluation of In[39]:= {1,2,3,4,5}

$Aborted

If you mind the formatting of parenthesis, you could explicitly use the FullForm of CompoundExpression like this:

CompoundExpression[
   Print@Range[5],
   Abort[],
   Print@Range[5],
]

Use of $PreRead

Suggested by Alexey Popkov:

In[1]:= $new$PreRead = False;
AbortAllPendingInputs := 
  AbortProtect[If[! $new$PreRead, $new$PreRead = True;
    $TimeOfAbort = SessionTime[];
    last$PreRead = ToString[Definition[$PreRead], InputForm];
    ClearAll[$PreRead];
    $PreRead := If[TrueQ[SessionTime[] - $TimeOfAbort < 1], "",
       $new$PreRead = False;
       ClearAll[$PreRead];
       If[last$PreRead === "Null", #, 
        ToExpression[last$PreRead]; $PreRead@#]
       ] &;]];

In[3]:= f := CheckAbort[Pause[10], AbortAllPendingInputs; Abort[]]

In[4]:= While[True, f]
While[True, f]
While[True, f]

Out[4]= $Aborted

Note that this solution will need to be modified if you use $PreRead for anything else.

Use of CellEvaluationFunction

CellEvaluationFunction gets the BoxData expression, before it is even split. Just assigning something like CellEvaluationFunction:>ToExpression seems to do the trick.

You can set it as an Input cell style, or as a notebook option, or front end session option, or however you like

SetOptions[$FrontEndSession, CellEvaluationFunction :> ToExpression]

However, you lose the multiple outputs in those new lines when you don't use ;. This can probably be solved but I don't know very well how CellEvalutionFunction works, and how can it receive a box structure, default to Identity but expect to return an expression. Edit should you come up with any improvements

Answer 2

Note that the documentation FrontEnd uses CellEvaluationFunction -> Identity and not ToExpression. Still the example works and

Print[a]; Abort[]; Print[b]

aborts properly (not printing b) because all statements are in one line. Apparently it is the line breaks which break up the cell into individual commands, not the semicolons. So there must be another way "fixing" this.