Tagged Questions
0
votes
1answer
34 views
Clojure - inversion of control macro - Timothy Baldridge
In this podcast on core.async at approximately 12 mins in, Rich Hickey refers to a macro written by Timothy Baldridge that does 'inversion of control'. That this macro rewrites code into a state ...
1
vote
2answers
21 views
How to catch IllegalArgumentException in tests using thrown-with-msg?
I try to test the throw of an exception:
;;; src
;; Courtesy https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj
(defmacro assert-args [& pairs]
`(do (when-not ~(first ...
2
votes
2answers
44 views
Issue with clojure macro returning map with java object
I'm very new to macros so I have a basic question that seems to do with the way that Java objects are represented in Clojure code. I have a macro that should return a map:
(defmacro g []
(let [m ...
1
vote
2answers
75 views
How can I avoid evaluation of a lazy-seq inside a collection
I'm trying to write a debug macro that prints out expressions and their values. This lead to problems if I send in a lazy-seq, because if I turn it into a string (with str) the program hangs. It's ...
3
votes
1answer
44 views
Why doesn't my macro give any output
I wrote a simple macro for printing out expressions and their results when debugging.
(defmacro dbg-print
"Print out values or expressions in context"
[& rest]
`(let [symb-str# (map str ...
5
votes
1answer
92 views
Starting points to morph regular Servlets coding to my DSL
Clojure offers a good Java interop. However, I really want to have this:
(servlet IndexServlet
(service[parmas] ....)
(do-post[params] ....)
(do-get [params] ....))
(servlet-filter ...
3
votes
1answer
44 views
Reverting to global scope in macro in clojure?
I want to make a macro which defines a function outside of the local variable scope, as to catch errors where the programmer (aka me) is incorrectly referencing variables in the local scope. It should ...
2
votes
1answer
58 views
Clojure macro Instantiation Exception
I have a macro which works in the repl, and it seems to work in my code outside the let and also inside the let as follows. However it also breaks and I have no idea why. The macro basically just ...
2
votes
1answer
96 views
How to test a clojure macro that uses gensyms?
I want to test a macro that uses gensyms. For example, if I want to test this:
(defmacro m1
[x f]
`(let [x# ~x]
(~f x#)))
I can use macro-expansion...
(macroexpand-1 '(m1 2 inc))
...to ...
4
votes
1answer
72 views
Clojure How to Expand Macro in Source File Versus Repl
I am leaning macros in Clojure and have a question about macro expansion. In the repl, when I do this:
user=> (defmacro unless [pred a b] `(if (not ~pred) ~a ~b))
#'user/unless
user=> ...
1
vote
2answers
51 views
How do you transform a vector of maps into a series of symbols that eval to a particular map?
I am a Clojure newbie using Light Table to learn macros. My goal is to convert a vector of maps into a list of def statements.
I want to transform the following data structure:
(def label-data
[
...
2
votes
2answers
79 views
How to use defmacro instead of eval?
I have come up with the below function, which works as intended but it uses eval which is horrible, and does not exist in ClojureScript where i intend to use it.
(defn path [d p]
(eval
(concat ...
2
votes
2answers
87 views
Clojure macro that doesn't need space next to it
Trying to create a macro form of Haskell's lambda syntax, I'm pretty close except one last tweak, the / (which should be a \, but can't grumble..) needs a space next to it, is there any way to make it ...
1
vote
1answer
36 views
Macro want to use symbol instead of string in clojure
So trying to make something like the haskell lambda syntax, and with a macro this is what I've got:
(defmacro / [& all]
(let [args (take-while #(not (= %1 "=>")) all)
argCount (count ...
2
votes
3answers
136 views
Backquote without parens
I am working through the excellent book Let Over Lambda, and I am trying to port the Common Lisp code for defunits over to Clojure.
The following generates a macro that is supposed to take
(defn ...
