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Merge pull request #422 from MikeBeller/compare

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Implement polymorphic compare
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Calvin Rose 2020-06-10 00:58:33 -04:00 committed by GitHub
commit 2a9923999b
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3 changed files with 260 additions and 33 deletions
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60
src/boot/boot.janet
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@ -667,6 +667,66 @@
[xs]
(get xs (- (length xs) 1)))
## Polymorphic comparisons
(defn compare-primitive
"Compare x and y using primitive operators.
Returns -1,0,1 for x < y, x = y, x > y respectively.
Present mostly for constructing 'compare' methods in prototypes."
[x y]
(cond
(= x y) 0
(< x y) -1
(> x y) 1))
(defn compare
"Polymorphic compare. Returns -1,0,1 for x < y, x = y, x > y respectively.
Differs from the primitive comparators in that it first checks to
see whether either x or y implement a 'compare' method which can
compare x and y. If so it uses that compare method. If not, it
delegates to the primitive comparators."
[x y]
(or
(when-let [f (get x :compare)] (f x y))
(when-let [f (get y :compare)
fyx (f y x)] (- fyx))
(compare-primitive x y)))
(defn compare-reduce- [op xs]
(var r true)
(loop [i :range [0 (- (length xs) 1)]
:let [c (compare (xs i) (xs (+ i 1)))
ok (op c 0)]
:when (not ok)]
(set r false)
(break))
r)
(defn compare=
"Equivalent of '=' but using compare function instead of primitive comparator"
[& xs]
(compare-reduce- = xs))
(defn compare<
"Equivalent of '<' but using compare function instead of primitive comparator"
[& xs]
(compare-reduce- < xs))
(defn compare<=
"Equivalent of '<=' but using compare function instead of primitive comparator"
[& xs]
(compare-reduce- <= xs))
(defn compare>
"Equivalent of '>' but using compare function instead of primitive comparator"
[& xs]
(compare-reduce- > xs))
(defn compare>=
"Equivalent of '>=' but using compare function instead of primitive comparator"
[& xs]
(compare-reduce- >= xs))
###
###
### Indexed Combinators

152
src/core/inttypes.c
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@ -197,6 +197,122 @@ static Janet cfun_it_u64_new(int32_t argc, Janet *argv) {
return janet_wrap_u64(janet_unwrap_u64(argv[0]));
}
// Code to support polymorphic comparison.
//
// int/u64 and int/s64 support a "compare" method that allows
// comparison to each other, and to Janet numbers, using the
// "compare" "compare<" ... functions.
//
// In the following code explicit casts are sometimes used to help
// make it clear when int/float conversions are happening.
//
static int64_t compare_double_double(double x, double y) {
return (x < y) ? -1 : ((x > y) ? 1 : 0);
}
static int64_t compare_int64_double(int64_t x, double y) {
if (isnan(y)) {
return 0; // clojure and python do this
} else if ((y > ((double) -MAX_INT_IN_DBL)) && (y < ((double) MAX_INT_IN_DBL))) {
double dx = (double) x;
return compare_double_double(dx, y);
} else if (y > ((double) INT64_MAX)) {
return -1;
} else if (y < ((double) INT64_MIN)) {
return 1;
} else {
int64_t yi = (int64_t) y;
return (x < yi) ? -1 : ((x > yi) ? 1 : 0);
}
}
static int64_t compare_uint64_double(uint64_t x, double y) {
if (isnan(y)) {
return 0; // clojure and python do this
} else if (y < 0) {
return 1;
} else if ((y >= 0) && (y < ((double) MAX_INT_IN_DBL))) {
double dx = (double) x;
return compare_double_double(dx, y);
} else if (y > ((double) UINT64_MAX)) {
return -1;
} else {
uint64_t yi = (uint64_t) y;
return (x < yi) ? -1 : ((x > yi) ? 1 : 0);
}
}
static Janet cfun_it_s64_compare(int32_t argc, Janet *argv) {
janet_fixarity(argc, 2);
if (janet_is_int(argv[0]) != JANET_INT_S64)
janet_panic("compare method requires int/s64 as first argument");
int64_t x = janet_unwrap_s64(argv[0]);
switch (janet_type(argv[1])) {
default:
break;
case JANET_NUMBER : {
double y = janet_unwrap_number(argv[1]);
return janet_wrap_number(compare_int64_double(x, y));
}
case JANET_ABSTRACT: {
void *abst = janet_unwrap_abstract(argv[1]);
if (janet_abstract_type(abst) == &janet_s64_type) {
int64_t y = *(int64_t *)abst;
return janet_wrap_number((x < y) ? -1 : (x > y ? 1 : 0));
} else if (janet_abstract_type(abst) == &janet_u64_type) {
// comparing signed to unsigned -- be careful!
uint64_t y = *(uint64_t *)abst;
if (x < 0) {
return janet_wrap_number(-1);
} else if (y > INT64_MAX) {
return janet_wrap_number(-1);
} else {
int64_t y2 = (int64_t) y;
return janet_wrap_number((x < y2) ? -1 : (x > y2 ? 1 : 0));
}
}
break;
}
}
return janet_wrap_nil();
}
static Janet cfun_it_u64_compare(int32_t argc, Janet *argv) {
janet_fixarity(argc, 2);
if (janet_is_int(argv[0]) != JANET_INT_U64) // is this needed?
janet_panic("compare method requires int/u64 as first argument");
uint64_t x = janet_unwrap_u64(argv[0]);
switch (janet_type(argv[1])) {
default:
break;
case JANET_NUMBER : {
double y = janet_unwrap_number(argv[1]);
return janet_wrap_number(compare_uint64_double(x, y));
}
case JANET_ABSTRACT: {
void *abst = janet_unwrap_abstract(argv[1]);
if (janet_abstract_type(abst) == &janet_u64_type) {
uint64_t y = *(uint64_t *)abst;
return janet_wrap_number((x < y) ? -1 : (x > y ? 1 : 0));
} else if (janet_abstract_type(abst) == &janet_s64_type) {
// comparing unsigned to signed -- be careful!
int64_t y = *(int64_t *)abst;
if (y < 0) {
return janet_wrap_number(1);
} else if (x > INT64_MAX) {
return janet_wrap_number(1);
} else {
int64_t x2 = (int64_t) x;
return janet_wrap_number((x2 < y) ? -1 : (x2 > y ? 1 : 0));
}
}
break;
}
}
return janet_wrap_nil();
}
#define OPMETHOD(T, type, name, oper) \
static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
janet_arity(argc, 2, -1); \
@ -266,14 +382,6 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
return janet_wrap_abstract(box); \
} \
#define COMPMETHOD(T, type, name, oper) \
static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
janet_fixarity(argc, 2); \
T v1 = janet_unwrap_##type(argv[0]); \
T v2 = janet_unwrap_##type(argv[1]); \
return janet_wrap_boolean(v1 oper v2); \
}
static Janet cfun_it_s64_mod(int32_t argc, Janet *argv) {
janet_arity(argc, 2, -1);
int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
@ -316,13 +424,6 @@ OPMETHOD(int64_t, s64, or, |)
OPMETHOD(int64_t, s64, xor, ^)
OPMETHOD(int64_t, s64, lshift, <<)
OPMETHOD(int64_t, s64, rshift, >>)
COMPMETHOD(int64_t, s64, lt, <)
COMPMETHOD(int64_t, s64, gt, >)
COMPMETHOD(int64_t, s64, le, <=)
COMPMETHOD(int64_t, s64, ge, >=)
COMPMETHOD(int64_t, s64, eq, ==)
COMPMETHOD(int64_t, s64, ne, !=)
OPMETHOD(uint64_t, u64, add, +)
OPMETHOD(uint64_t, u64, sub, -)
OPMETHODINVERT(uint64_t, u64, subi, -)
@ -336,18 +437,13 @@ OPMETHOD(uint64_t, u64, or, |)
OPMETHOD(uint64_t, u64, xor, ^)
OPMETHOD(uint64_t, u64, lshift, <<)
OPMETHOD(uint64_t, u64, rshift, >>)
COMPMETHOD(uint64_t, u64, lt, <)
COMPMETHOD(uint64_t, u64, gt, >)
COMPMETHOD(uint64_t, u64, le, <=)
COMPMETHOD(uint64_t, u64, ge, >=)
COMPMETHOD(uint64_t, u64, eq, ==)
COMPMETHOD(uint64_t, u64, ne, !=)
#undef OPMETHOD
#undef DIVMETHOD
#undef DIVMETHOD_SIGNED
#undef COMPMETHOD
static JanetMethod it_s64_methods[] = {
{"+", cfun_it_s64_add},
{"r+", cfun_it_s64_add},
@ -361,12 +457,6 @@ static JanetMethod it_s64_methods[] = {
{"rmod", cfun_it_s64_modi},
{"%", cfun_it_s64_rem},
{"r%", cfun_it_s64_remi},
{"<", cfun_it_s64_lt},
{">", cfun_it_s64_gt},
{"<=", cfun_it_s64_le},
{">=", cfun_it_s64_ge},
{"=", cfun_it_s64_eq},
{"!=", cfun_it_s64_ne},
{"&", cfun_it_s64_and},
{"r&", cfun_it_s64_and},
{"|", cfun_it_s64_or},
@ -375,6 +465,7 @@ static JanetMethod it_s64_methods[] = {
{"r^", cfun_it_s64_xor},
{"<<", cfun_it_s64_lshift},
{">>", cfun_it_s64_rshift},
{"compare", cfun_it_s64_compare},
{NULL, NULL}
};
@ -392,12 +483,6 @@ static JanetMethod it_u64_methods[] = {
{"rmod", cfun_it_u64_modi},
{"%", cfun_it_u64_mod},
{"r%", cfun_it_u64_modi},
{"<", cfun_it_u64_lt},
{">", cfun_it_u64_gt},
{"<=", cfun_it_u64_le},
{">=", cfun_it_u64_ge},
{"=", cfun_it_u64_eq},
{"!=", cfun_it_u64_ne},
{"&", cfun_it_u64_and},
{"r&", cfun_it_u64_and},
{"|", cfun_it_u64_or},
@ -406,6 +491,7 @@ static JanetMethod it_u64_methods[] = {
{"r^", cfun_it_u64_xor},
{"<<", cfun_it_u64_lshift},
{">>", cfun_it_u64_rshift},
{"compare", cfun_it_u64_compare},
{NULL, NULL}
};

81
test/suite0.janet
View File

@ -334,5 +334,86 @@
(assert (deep= @{:a 3 :b 2} @{:a 1 :b 2 :a 3}) "table literal duplicate keys")
(assert (deep= @{:a 3 :b 2} (table :a 1 :b 2 :a 3)) "table constructor duplicate keys")
## Polymorphic comparison -- Issue #272
# confirm polymorphic comparison delegation to primitive comparators:
(assert (= 0 (compare-primitive 3 3)) "compare-primitive integers (1)")
(assert (= -1 (compare-primitive 3 5)) "compare-primitive integers (2)")
(assert (= 1 (compare-primitive "foo" "bar")) "compare-primitive strings")
(assert (= 0 (compare 1 1)) "compare integers (1)")
(assert (= -1 (compare 1 2)) "compare integers (2)")
(assert (= 1 (compare "foo" "bar")) "compare strings (1)")
(assert (compare< 1 2 3 4 5 6) "compare less than integers")
(assert (not (compare> 1 2 3 4 5 6)) "compare not greater than integers")
(assert (compare< 1.0 2.0 3.0 4.0 5.0 6.0) "compare less than reals")
(assert (compare> 6 5 4 3 2 1) "compare greater than integers")
(assert (compare> 6.0 5.0 4.0 3.0 2.0 1.0) "compare greater than reals")
(assert (not (compare< 6.0 5.0 4.0 3.0 2.0 1.0)) "compare less than reals")
(assert (compare<= 1 2 3 3 4 5 6) "compare less than or equal to integers")
(assert (compare<= 1.0 2.0 3.0 3.0 4.0 5.0 6.0) "compare less than or equal to reals")
(assert (compare>= 6 5 4 4 3 2 1) "compare greater than or equal to integers")
(assert (compare>= 6.0 5.0 4.0 4.0 3.0 2.0 1.0) "compare greater than or equal to reals")
(assert (compare< 1.0 nil false true
(fiber/new (fn [] 1))
"hi"
(quote hello)
:hello
(array 1 2 3)
(tuple 1 2 3)
(table "a" "b" "c" "d")
(struct 1 2 3 4)
(buffer "hi")
(fn [x] (+ x x))
print) "compare type ordering")
# test polymorphic compare with 'objects' (table/setproto)
(def mynum
@{:type :mynum :v 0 :compare
(fn [self other]
(case (type other)
:number (compare-primitive (self :v) other)
:table (when (= (get other :type) :mynum)
(compare-primitive (self :v) (other :v)))))})
(let [n3 (table/setproto @{:v 3} mynum)]
(assert (= 0 (compare 3 n3)) "compare num to object (1)")
(assert (= -1 (compare n3 4)) "compare object to num (2)")
(assert (= 1 (compare (table/setproto @{:v 4} mynum) n3)) "compare object to object")
(assert (compare< 2 n3 4) "compare< poly")
(assert (compare> 4 n3 2) "compare> poly")
(assert (compare<= 2 3 n3 4) "compare<= poly")
(assert (compare= 3 n3 (table/setproto @{:v 3} mynum)) "compare= poly")
(assert (deep= (sorted @[4 5 n3 2] compare<) @[2 n3 4 5]) "polymorphic sort"))
(let [
MAX_INT_64_STRING "9223372036854775807"
MAX_UINT_64_STRING "18446744073709551615"
MAX_INT_IN_DBL_STRING "9007199254740991"
NAN (math/log -1)
INF (/ 1 0)
MINUS_INF (/ -1 0)
compare-poly-tests
[
[(int/s64 3) (int/u64 3) 0]
[(int/s64 -3) (int/u64 3) -1]
[(int/s64 3) (int/u64 2) 1]
[(int/s64 3) 3 0] [(int/s64 3) 4 -1] [(int/s64 3) -9 1]
[(int/u64 3) 3 0] [(int/u64 3) 4 -1] [(int/u64 3) -9 1]
[3 (int/s64 3) 0] [3 (int/s64 4) -1] [3 (int/s64 -5) 1]
[3 (int/u64 3) 0] [3 (int/u64 4) -1] [3 (int/u64 2) 1]
[(int/s64 MAX_INT_64_STRING) (int/u64 MAX_UINT_64_STRING) -1]
[(int/s64 MAX_INT_IN_DBL_STRING) (scan-number MAX_INT_IN_DBL_STRING) 0]
[(int/u64 MAX_INT_IN_DBL_STRING) (scan-number MAX_INT_IN_DBL_STRING) 0]
[(+ 1 (int/u64 MAX_INT_IN_DBL_STRING)) (scan-number MAX_INT_IN_DBL_STRING) 1]
[(int/s64 0) INF -1] [(int/u64 0) INF -1]
[MINUS_INF (int/u64 0) -1] [MINUS_INF (int/s64 0) -1]
[(int/s64 1) NAN 0] [NAN (int/u64 1) 0]
]]
(each [x y c] compare-poly-tests
(assert (= c (compare x y)) (string/format "compare polymorphic %q %q %d" x y c)))
)
(end-suite)