A special operator you'll need to understand in order to write certain kinds of macros is EVAL-WHEN.eval-when normally appears as a top level form, but it is meaningful for it to appear as a non-top-level form. However, the compile-time side effects.
Questions tagged [eval-when]
7 questions
15
votes
1 answer
In Common Lisp, when do you need to use eval-when, and how do you know?
A required use of eval-when is to ensure that functions which a macro depends on are available at the time the macro is compiled and is used. However, I can't think of an example that would demonstrate the consequences of not using…
anticrisis
- 918
- 1
- 8
- 17
15
votes
1 answer
Eval-when uses?
After reading a lot of documentation regarding Lisp eval-when operator I still can't understand its uses, I know with this operator I can control the evaluation time of my expressions but I can't figure out any example where this may be applicable…
utxeee
- 953
- 1
- 12
- 24
8
votes
2 answers
Common Lisp: How to get (in-package ...) to work from within Emacs Slime
64-bit Windows 7
Clozure Common Lisp Version 1.9 WindowsX8632
Emacs 24.3.1
Slime changelog date 2014-06-17
I have an example .lisp file which starts out as follows:
(ql:quickload 'qt)
(in-package "QT")
The rest of the program shows a dialog…
Sonicsmooth
- 2,673
- 2
- 22
- 35
2
votes
1 answer
Cyclomatic Complexity - Cobol
I have to calculate Cyclomatic Complexity for a Cobol program that contains only an EVALUATE like this one:
EVALUATE x
WHEN x<0 ...
WHEN x=0 ...
WHEN x between 1 and 10 ...
WHEN OTHER ...`
END EVALUATE.`
I have also to calculate…
Fede
- 21
- 1
0
votes
1 answer
How to properly use symbol property lists in common lisp macros
I am writing a Common Lisp macro define-computation which defines functions in a specific way and marks them by adding a property :computation to the property list of the symbol of the defined function.
The define-computation is looking for forms…
Michaël Le Barbier
- 6,103
- 5
- 28
- 57
0
votes
1 answer
Loading quicklisp package for use in another lisp file
I have downloaded a large software project FriCAS which I have compiled from source and using SBCL. This was just a matter of using GNU .configure - I am a complete Lisp newbie.
However, in order to add some further functionality I have - by very…
Alasdair
- 1,300
- 4
- 16
- 28
0
votes
1 answer
Comparing distinct items from collection in drools 6 when clause
I've searched around the internet but could not find an solution for a problem we are currently facing with drools (6.2.0).
Suppose i have a rule like this:
when
$list: ProductList()
$product: Product() from $list
$product2: Product(this…
Kim Zeevaarders
- 732
- 1
- 7
- 21