Support conversion between pointers and integrals

lib/memory.nelua

@@ -192,10 +192,9 @@ end
 
 function memory.spanset(dest: auto, x: auto)
   ## check_span_subtype_match(dest, x)
-  if likely(dest.size > 0_u) then
-    for i:usize=0,<dest.size do
-      dest[i] = x
-    end
+  local T: type = #[x.type]#
+  for i:usize=0,<dest.size do
+    memcpy(&dest[i], &x, #T)
   end
 end
 

nelua/types.lua

@@ -611,8 +611,12 @@ end
 function IntegralType:is_convertible_from_type(type, explicit)
   if type:is_integral() and self:is_inrange(type.min) and self:is_inrange(type.max) then
     return true
-  elseif explicit and type:is_arithmetic() then
-    return true
+  elseif explicit then
+    if type:is_arithmetic() then
+      return true
+    elseif type:is_pointer() and self.size == cpusize then
+      return true
+    end
   end
   return ArithmeticType.is_convertible_from_type(self, type, explicit)
 end
@@ -1255,6 +1259,8 @@ function PointerType:is_convertible_from_type(type, explicit)
     return true
   elseif type:is_nilptr() then
     return true
+  elseif explicit and type:is_integral() and type.size == cpusize then
+    return true
   end
   return Type.is_convertible_from_type(self, type, explicit)
 end

spec/03-typechecker_spec.lua

@@ -1043,6 +1043,11 @@ it("pointers", function()
     b = nilptr
     a = nilptr
   ]])
+  assert.analyze_ast([[
+    local x: usize = 1
+    local p: pointer = (@pointer)(x)
+    x = (@usize)(p)
+  ]])
   assert.ast_type_equals(
     "local a = (@pointer)(nilptr) a = nilptr",
     "local a: pointer = (@pointer)(nilptr) a = nilptr")
@@ -1070,6 +1075,14 @@ it("pointers", function()
     local b: pointer(cchar)
     b = a
   ]])
+  assert.analyze_error([[
+    local x: byte = 1
+    local p: pointer = (@pointer)(x)
+  ]], "no viable type conversion")
+  assert.analyze_error([[
+    local p: pointer
+    local x: byte = (@byte)(p)
+  ]], "no viable type conversion")
   assert.analyze_error([[
     local a: pointer(integer)
     local b: pointer(boolean)

spec/05-cgenerator_spec.lua

@@ -1276,13 +1276,27 @@ it("pointers", function()
     local function f(a: pointer): pointer return a end
     local i: integer = 1
     local p: pointer(integer) = &i
-    print($p)
+    assert($p == 1)
     p = (@pointer(int64))(f(p))
     i = 2
-    print($p)
+    assert($p == 2)
     $p = 3
-    print(i)
-  ]], "1\n2\n3")
+    assert(i == 3)
+
+    do
+      local x: usize = 0xffffffff
+      local p: pointer = (@pointer)(x)
+      x = (@usize)(p)
+      assert(x == 0xffffffff)
+    end
+
+    do
+      local x: isize = -1
+      local p: pointer = (@pointer)(x)
+      x = (@isize)(p)
+      assert(x == -1)
+    end
+  ]])
 end)
 
 it("function pointers", function()

tests/memory_test.nelua

@@ -208,15 +208,21 @@ end
 do -- spancompare
   local pa = memory.spanalloc0(@vec2, 1)
   local pb = memory.spanalloc0(@vec2, 1)
+  local pc = memory.spanalloc0(@vec2, 0)
   assert(memory.spancompare(pa, pb) == 0)
   pa[0].x = 1 pb[0].x = 2
   assert(memory.spancompare(pa, pb) == -1)
+  assert(memory.spancompare(pb, pa) == 1)
   pa[0].x = 2 pb[0].x = 1
   assert(memory.spancompare(pa, pb) == 1)
+  assert(memory.spancompare(pb, pa) == -1)
   pa[0].x = 2 pb[0].x = 2
   assert(memory.spancompare(pa, pb) == 0)
+  assert(memory.spancompare(pa, pc) == 1)
+  assert(memory.spancompare(pc, pa) == -1)
   memory.spandealloc(pa)
   memory.spandealloc(pb)
+  memory.spandealloc(pc)
 end
 
 do -- spanequals