From 803f17aa904d250b74d5938e8f038f01aaa59efa Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 21 Jun 2020 18:48:06 -0500
Subject: [PATCH] Add eachy and repeat to make looping easier.

Like eachk and eachp, use eachy and repeat to bring loop
verbs outside of the loop macro. These new macros are very simple
and easy to understand, in contrast to the loop macro which is of
medium complexity.
---
 src/boot/boot.janet | 33 +++++++++++++++++++++++++--------
 src/core/run.c      |  1 -
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/boot/boot.janet b/src/boot/boot.janet
index 4474a458..ac8cbf90 100644
--- a/src/boot/boot.janet
+++ b/src/boot/boot.janet
@@ -433,6 +433,17 @@
          (def ,binding ,i)
          ,body))))
 
+(defn- loop-fiber-template
+  [binding expr body]
+  (with-syms [f s]
+    (def ds (if (idempotent? binding) binding (gensym)))
+    ~(let [,f ,expr]
+       (while true
+         (def ,ds (,resume ,f))
+         (if (= :dead (,fiber/status ,f)) (break))
+         ,;(if (= ds binding) [] [~(def ,binding ,ds)])
+         ,;body))))
+
 (defn- loop1
   [body head i]
 
@@ -470,14 +481,7 @@
       :pairs (keys-template binding object true [rest])
       :in (each-template binding object [rest])
       :iterate (iterate-template binding object rest)
-      :generate (with-syms [f s]
-                   (def ds (if (idempotent? binding) binding (gensym)))
-                  ~(let [,f ,object]
-                     (while true
-                       (def ,ds (,resume ,f))
-                       (if (= :dead (,fiber/status ,f)) (break))
-                       ,;(if (= ds binding) [] [~(def ,binding ,ds)])
-                       ,rest)))
+      :generate (loop-fiber-template binding object [rest])
       (error (string "unexpected loop verb " verb)))))
 
 (defmacro for
@@ -495,6 +499,18 @@
   [x ds & body]
   (keys-template x ds true body))
 
+(defmacro eachy
+  "Resume a fiber in a loop until it has errored or died. Evaluate the body
+  of the loop with binding set to the yielded value."
+  [x fiber & body]
+  (loop-fiber-template x fiber body))
+
+(defmacro repeat
+  "Evaluate body n times. If n is negative, body will be evaluated 0 times. Evaluates to nil."
+  [n & body]
+  (with-syms [iter]
+    ~(do (var ,iter ,n) (while (> ,iter 0) ,;body (-- ,iter)))))
+
 (defmacro each
   "Loop over each value in ds. Returns nil."
   [x ds & body]
@@ -544,6 +560,7 @@
 (put _env 'each-template nil)
 (put _env 'keys-template nil)
 (put _env 'range-template nil)
+(put _env 'loop-fiber-template nil)
 
 (defmacro seq
   "Similar to loop, but accumulates the loop body into an array and returns that.
diff --git a/src/core/run.c b/src/core/run.c
index 039d1144..4e88ca36 100644
--- a/src/core/run.c
+++ b/src/core/run.c
@@ -23,7 +23,6 @@
 #ifndef JANET_AMALG
 #include "features.h"
 #include <janet.h>
-#include "state.h"
 #endif
 
 /* Run a string */