Linked Questions

165 votes
5 answers

Are you interested in purchasing David Wagner's "Power programming with Mathematica"?

I recently contacted McGraw-Hill to see if they have a mechanism in place for printing out-of-print books that are still of interest. Specifically, I asked about "Power programming with Mathematica" ...
22 votes
2 answers

How does Mathematica determine that an evaluation should be terminated?

How exactly does Mathematica determine that evaluation of particular expression should be finished and the result should be returned? Here are some examples of unclear behavior which have arisen, ...
Alexey Popkov's user avatar
24 votes
3 answers

Why x = x doesn't cause an infinite loop, but f[x_] := f[x] does?

If I execute: In[1] := x = x Out[1] = x and then I evaluate the symbol x: ...
a06e's user avatar
  • 11.4k
7 votes
5 answers

How to display operations on list elements

When applying some arithmetic operation on two lists, I'd like to display the actual operations between the elements of each list. For example, {1, 1} + {1, -1} ...
seismatica's user avatar
  • 5,121
6 votes
2 answers

Manipulating slots in a pure function

How does one manipulate the slot numbers in a pure function? Some trick with Evaluate or Hold? I'm aiming for something along ...
mfvonh's user avatar
  • 8,470
9 votes
1 answer

Performance of Dispatch and lists of Rules

The issue outlined here seems to be no longer present in version 10, if you use a Dispatch table! This because a Dispatch table ...
Jacob Akkerboom's user avatar
9 votes
1 answer

Unevaluated @ {args} versus Unevaluated /@ {args}

Working my way through Robby Villegas's lovely notes on withholding evaluation, I almost got Polish Notation on my first try. Here is my final solution, which seems to work well enough: ...
Reb.Cabin's user avatar
  • 8,693
5 votes
2 answers

Return unevaluated expression from function

Is there any way (except using upvalues) to make a function that returns it's input Unevaluated? What I mean by that: Take the following example: ...
Lukas Lang's user avatar
  • 34.2k
1 vote
1 answer

How to put a Hold on a variable so it can be set

I've got a weird problem here.... So I have a function that takes blocks of codes and them uses Map on them and passes them around and then selects and returns the one that is needed. A simplified ...
kozner's user avatar
  • 283
8 votes
1 answer

Help me understand this behaviour of the standard evaluation procedure with `Unevaluated`

Wagner's book says that, in the Standard Evaluation Procedure, If no applicable rules where found and any of the part_i has the head Unevaluated, restore ...
masterxilo's user avatar
  • 5,739
3 votes
0 answers

I am missing a function like HoldPattern

Temporary message: I am planning to edit this question, making the examples less confusing and by moving the things that are confusing to a separate question For any confusion about expressions that ...
Jacob Akkerboom's user avatar