mirrors/janet
1
0
Fork 0
mirror of https://github.com/janet-lang/janet synced 2024-12-29 18:00:26 +00:00
Code Issues 1 Releases Wiki Activity

Remove duplicate code in loop macro.

Browse Source 
Also evaluate for loop and range step exactly once.
Multiple evaluations can be inefficent and make infinite loop
detection impossible.
This commit is contained in:
Calvin Rose 2020-07-01 22:37:04 -05:00
parent e548e1f6e0
commit 97c64f27ff
1 changed files with 21 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
src/boot/boot.janet
View File

@ -379,26 +379,23 @@
,(apply defer [(or dtor :close) binding] [truthy])
,falsey))
(defn- for-template
[binding start stop step comparison delta body]
(with-syms [i s]
~(do
(var ,i ,start)
(def ,s ,stop)
(while (,comparison ,i ,s)
(def ,binding ,i)
,;body
(set ,i (,delta ,i ,step))))))
(defn- for-var-template
[i start stop step comparison delta body]
(with-syms [s]
(def st (if (idempotent? step) step (gensym)))
~(do
(var ,i ,start)
(def ,s ,stop)
,;(if (= st step) [] [~(def ,st ,step)])
(while (,comparison ,i ,s)
,;body
(set ,i (,delta ,i ,step))))))
(set ,i (,delta ,i ,st))))))
(defn- for-template
[binding start stop step comparison delta body]
(def i (gensym))
(for-var-template i start stop step comparison delta
[~(def ,binding ,i) ;body]))
(defn- check-indexed [x]
(if (indexed? x)
@ -411,26 +408,18 @@
(for-template binding start stop (or step 1) comparison op [rest])))
(defn- each-template
[binding inx body]
[binding inx kind body]
(with-syms [k]
(def ds (if (idempotent? inx) inx (gensym)))
~(do
,(unless (= ds inx) ~(def ,ds ,inx))
(var ,k (,next ,ds nil))
(while (,not= nil ,k)
(def ,binding (,in ,ds ,k))
,;body
(set ,k (,next ,ds ,k))))))
(defn- keys-template
[binding in pair? body]
(with-syms [k]
(def ds (if (idempotent? in) in (gensym)))
~(do
,(unless (= ds in) ~(def ,ds ,in))
(var ,k (,next ,ds nil))
(while (,not= nil ,k)
(def ,binding ,(if pair? ~(tuple ,k (in ,ds ,k)) k))
(def ,binding
,(case kind
:each ~(,in ,ds ,k)
:keys k
:pairs ~(,tuple ,k (,in ,ds ,k))))
,;body
(set ,k (,next ,ds ,k))))))
@ -487,9 +476,9 @@
:range-to (range-template binding object rest + <=)
:down (range-template binding object rest - >)
:down-to (range-template binding object rest - >=)
:keys (keys-template binding object false [rest])
:pairs (keys-template binding object true [rest])
:in (each-template binding object [rest])
:keys (each-template binding object :keys [rest])
:pairs (each-template binding object :pairs [rest])
:in (each-template binding object :each [rest])
:iterate (iterate-template binding object rest)
:generate (loop-fiber-template binding object [rest])
(error (string "unexpected loop verb " verb)))))
@ -508,12 +497,12 @@
(defmacro eachk
"Loop over each key in ds. Returns nil."
[x ds & body]
(keys-template x ds false body))
(each-template x ds :each body))
(defmacro eachp
"Loop over each (key, value) pair in ds. Returns nil."
[x ds & body]
(keys-template x ds true body))
(each-template x ds :pairs body))
(defmacro eachy
"Resume a fiber in a loop until it has errored or died. Evaluate the body
@ -530,7 +519,7 @@
(defmacro each
"Loop over each value in ds. Returns nil."
[x ds & body]
(each-template x ds body))
(each-template x ds :each body))
(defmacro loop
"A general purpose loop macro. This macro is similar to the Common Lisp
@ -575,7 +564,6 @@
(put _env 'for-var-template nil)
(put _env 'iterate-template nil)
(put _env 'each-template nil)
(put _env 'keys-template nil)
(put _env 'range-template nil)
(put _env 'loop-fiber-template nil)