carp-lang/Carp
1
1
Fork 0
mirror of https://github.com/carp-lang/Carp.git synced 2024-09-11 05:25:28 +03:00
Code Issues Projects Releases Wiki Activity

macros: add cxr, nthcar, and nthcdr

Browse Source
This commit is contained in:
hellerve 2019-11-09 12:52:11 +01:00
parent 16e9418d25
commit bc87e82d9f
1 changed files with 19 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
core/Macros.carp
View File

@ -73,6 +73,25 @@
(defndynamic cdddar [pair] (cdr (cdr (cdr (car pair)))))
(defndynamic cddddr [pair] (cdr (cdr (cdr (cdr pair)))))
(defndynamic cxr [x pair]
(if (= (length x) 0)
(list 'quote pair)
(list
(if (= 'a (cadr x))
'car
(if (= 'd (cadr x))
'cdr
(macro-error "`cxr` expects either `a` or `d` symbols, got " (cadr x))))
(if (= 1 (car x))
(cxr (cddr x) pair)
(cxr (cons (- (car x) 1) (cdr x)) pair)))))
(defndynamic nthcdr [n pair]
(cxr (list n 'd) pair))
(defndynamic nthcar [n pair]
(cxr (list 1 'a n 'd) pair))
(defndynamic eval-internal [form]
(list 'do
(list 'defn 'main [] (list 'IO.println* form))