Make negative indexing work like python.

This would break a lot of code :|

src/boot/boot.janet

@@ -700,7 +700,7 @@
     4 (let [[f g h i] functions] (fn [& x] (f (g (h (i ;x))))))
     (let [[f g h i] functions]
       (comp (fn [x] (f (g (h (i x)))))
-            ;(tuple/slice functions 4 -1)))))
+            ;(tuple/slice functions 4)))))
 
 (defn identity
   "A function that returns its argument."
@@ -1208,7 +1208,7 @@
   (assert (symbol? alias) "alias must be a symbol")
   (assert (and (> (length alias) 2) (= 42 (first alias) (last alias))) "name must have leading and trailing '*' characters")
   (def prefix (dyn :defdyn-prefix))
-  (def kw (keyword prefix (slice alias 1 -2)))
+  (def kw (keyword prefix (slice alias 1 -1)))
   ~(def ,alias :dyn ,;more ,kw))
 
 (defn has-key?
@@ -1821,7 +1821,7 @@
   # Partition body into sections.
   (def oddlen (odd? (length cases)))
   (def else (if oddlen (last cases)))
-  (def patterns (partition 2 (if oddlen (slice cases 0 -2) cases)))
+  (def patterns (partition 2 (if oddlen (slice cases 0 -1) cases)))
 
   # Keep an array for accumulating the compilation output
   (def x-sym (if (idempotent? x) x (gensym)))
@@ -2052,7 +2052,7 @@
     (tuple/slice
       (array/concat
         @[(in t 0) (expand-bindings bound)]
-        (tuple/slice t 2 -2)
+        (tuple/slice t 2 -1)
         @[(recur last)])))
 
   (defn expandall [t]
@@ -2227,7 +2227,7 @@
   [name & body]
   (def expansion (apply defn name body))
   (def fbody (last expansion))
-  (def modifiers (tuple/slice expansion 2 -2))
+  (def modifiers (tuple/slice expansion 2 -1))
   (def metadata @{})
   (each m modifiers
     (cond
@@ -2917,7 +2917,7 @@
     (def buf @"")
     (with-dyns [*err* buf *err-color* false]
       (bad-parse x y))
-    (set exit-error (string/slice buf 0 -2)))
+    (set exit-error (string/slice buf 0 -1)))
   (defn bc [&opt x y z a b]
     (when exit
       (bad-compile x y z a b)
@@ -2926,7 +2926,7 @@
     (def buf @"")
     (with-dyns [*err* buf *err-color* false]
       (bad-compile x nil z a b))
-    (set exit-error (string/slice buf 0 -2))
+    (set exit-error (string/slice buf 0 -1))
     (set exit-fiber y))
   (unless f
     (error (string "could not find file " path)))
@@ -3789,7 +3789,7 @@
     "Generate bindings for native functions in a convenient manner."
     [name ret-type & body]
     (def real-ret-type (eval ret-type))
-    (def meta (slice body 0 -2))
+    (def meta (slice body 0 -1))
     (def arg-pairs (partition 2 (last body)))
     (def formal-args (map 0 arg-pairs))
     (def type-args (map 1 arg-pairs))

src/core/array.c

@@ -297,7 +297,7 @@ JANET_CORE_FN(cfun_array_remove,
     int32_t at = janet_getinteger(argv, 1);
     int32_t n = 1;
     if (at < 0) {
-        at = array->count + at + 1;
+        at = array->count + at;
     }
     if (at < 0 || at > array->count)
         janet_panicf("removal index %d out of range [0,%d]", at, array->count);

src/core/capi.c

@@ -334,20 +334,11 @@ size_t janet_getsize(const Janet *argv, int32_t n) {
 }
 
 int32_t janet_gethalfrange(const Janet *argv, int32_t n, int32_t length, const char *which) {
-    int32_t raw = janet_getinteger(argv, n);
-    int32_t not_raw = raw;
-    if (not_raw < 0) not_raw += length + 1;
-    if (not_raw < 0 || not_raw > length)
-        janet_panicf("%s index %d out of range [%d,%d]", which, raw, -length - 1, length);
-    return not_raw;
-}
-
-int32_t janet_getargindex(const Janet *argv, int32_t n, int32_t length, const char *which) {
     int32_t raw = janet_getinteger(argv, n);
     int32_t not_raw = raw;
     if (not_raw < 0) not_raw += length;
     if (not_raw < 0 || not_raw > length)
-        janet_panicf("%s index %d out of range [%d,%d)", which, raw, -length, length);
+        janet_panicf("%s index %d out of range [%d,%d]", which, raw, -length, length);
     return not_raw;
 }
 

src/include/janet.h

@@ -1997,7 +1997,6 @@ JANET_API JanetDictView janet_getdictionary(const Janet *argv, int32_t n);
 JANET_API void *janet_getabstract(const Janet *argv, int32_t n, const JanetAbstractType *at);
 JANET_API JanetRange janet_getslice(int32_t argc, const Janet *argv);
 JANET_API int32_t janet_gethalfrange(const Janet *argv, int32_t n, int32_t length, const char *which);
-JANET_API int32_t janet_getargindex(const Janet *argv, int32_t n, int32_t length, const char *which);
 JANET_API uint64_t janet_getflags(const Janet *argv, int32_t n, const char *flags);
 
 /* Optionals */

test/helper.janet

@@ -44,7 +44,7 @@
          (number? x) (string x)
          (string? x) (string/slice x
                                    (length "test/suite-")
-                                   (- (inc (length ".janet"))))
+                                   (- (length ".janet")))
          (string x)))
   (set start-time (os/clock))
   (eprint "Starting suite " suite-name "..."))

test/suite-array.janet

@@ -37,14 +37,14 @@
 (assert (array= @[:one :two :three :four :five]
                 @[:one :two :three :four :five]) "array comparison 3")
 (assert (array= (array/slice @[1 2 3] 0 2) @[1 2]) "array/slice 1")
-(assert (array= (array/slice @[0 7 3 9 1 4] 2 -2) @[3 9 1]) "array/slice 2")
+(assert (array= (array/slice @[0 7 3 9 1 4] 2 -1) @[3 9 1]) "array/slice 2")
 
 # Array remove
 # 687a3c9
 (assert (deep= (array/remove @[1 2 3 4 5] 2) @[1 2 4 5]) "array/remove 1")
 (assert (deep= (array/remove @[1 2 3 4 5] 2 2) @[1 2 5]) "array/remove 2")
 (assert (deep= (array/remove @[1 2 3 4 5] 2 200) @[1 2]) "array/remove 3")
-(assert (deep= (array/remove @[1 2 3 4 5] -3 200) @[1 2 3]) "array/remove 4")
+(assert (deep= (array/remove @[1 2 3 4 5] -2 200) @[1 2 3]) "array/remove 4")
 
 
 # array/peek

test/suite-buffer.janet

@@ -96,13 +96,13 @@
 # Regression #301
 # a3d4ecddb
 (def b (buffer/new-filled 128 0x78))
-(assert (= 38 (length (buffer/blit @"" b -1 90))) "buffer/blit 1")
+(assert (= 38 (length (buffer/blit @"" b 0 90))) "buffer/blit 1")
 
 (def a @"abcdefghijklm")
-(assert (deep= @"abcde" (buffer/blit @"" a -1 0 5)) "buffer/blit 2")
-(assert (deep= @"bcde" (buffer/blit @"" a -1 1 5)) "buffer/blit 3")
-(assert (deep= @"cde" (buffer/blit @"" a -1 2 5)) "buffer/blit 4")
-(assert (deep= @"de" (buffer/blit @"" a -1 3 5)) "buffer/blit 5")
+(assert (deep= @"abcde" (buffer/blit @"" a 0 0 5)) "buffer/blit 2")
+(assert (deep= @"bcde" (buffer/blit @"" a 0 1 5)) "buffer/blit 3")
+(assert (deep= @"cde" (buffer/blit @"" a 0 2 5)) "buffer/blit 4")
+(assert (deep= @"de" (buffer/blit @"" a 0 3 5)) "buffer/blit 5")
 
 # buffer/push-at
 # c55d93512

test/suite-parse.janet

@@ -69,7 +69,7 @@
 
   (def first-nl (= (chr "\n") (first str)))
   (def last-nl (= (chr "\n") (last str)))
-  (string/slice str (if first-nl 1 0) (if last-nl -2)))
+  (string/slice str (if first-nl 1 0) (if last-nl -1)))
 
 (defn reindent-reference
   "Same as reindent but use parser functionality. Useful for

test/suite-pp.janet

@@ -32,10 +32,10 @@
 # Buffer self blitting, check for use after free
 # bbcfaf128
 (def buf1 @"1234567890")
-(buffer/blit buf1 buf1 -1)
-(buffer/blit buf1 buf1 -1)
-(buffer/blit buf1 buf1 -1)
-(buffer/blit buf1 buf1 -1)
+(buffer/blit buf1 buf1 (length buf1))
+(buffer/blit buf1 buf1 (length buf1))
+(buffer/blit buf1 buf1 (length buf1))
+(buffer/blit buf1 buf1 (length buf1))
 (assert (= (string buf1) (string/repeat "1234567890" 16))
         "buffer blit against self")