Specify output array data types (#57)

Author: kgryte

spec/API_specification/creation_functions.md

@@ -33,7 +33,7 @@ Returns evenly spaced values within the half-open interval `[start, stop)` as a
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 
@@ -53,7 +53,7 @@ Returns an uninitialized array having a specified `shape`.
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 
@@ -101,7 +101,7 @@ Returns a two-dimensional array with ones on the `k`th diagonal and zeros elsewh
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 
@@ -125,7 +125,7 @@ Returns a new array having a specified `shape` and filled with `fill_value`.
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 
@@ -179,7 +179,7 @@ Returns evenly spaced numbers over a specified interval.
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 -   **endpoint**: _Optional\[ bool ]_
 
@@ -203,7 +203,7 @@ Returns a new array having a specified `shape` and filled with ones.
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 
@@ -243,7 +243,7 @@ Returns a new array having a specified `shape` and filled with zeros.
 
 -   **dtype**: _Optional\[ <dtype> ]_ 
 
-    -   output array data type. Default: `None`.
+    -   output array data type. If `dtype` is `None`, the output array data type must be the default floating-point data type. Default: `None`.
 
 #### Returns
 

spec/API_specification/data_types.md

@@ -6,16 +6,28 @@
 
 A conforming implementation of the array API standard must provide and support the following data types.
 
+.. note::
+
+    Data types ("dtypes") are objects that can be used as `dtype` specifiers in functions and methods (e.g., `zeros((2, 3), dtype=float32)`). A conforming implementation may add methods or attributes to data type objects; however, these methods and attributes are not included in this specification.
+
+.. note::
+
+    Implementations may provide other ways to specify data types (e.g.,
+    `zeros((2, 3), dtype='f4')`); however, these are not included in this specification.
+
 A conforming implementation of the array API standard may provide and support additional data types beyond those described in this specification.
 
+A conforming implementation of the array API standard must define a default floating-point data type (either `float32` or `float64`).
+
 .. note::
 
-    These dtypes are objects that can be used as dtype specifiers in functions and methods (e.g., `zeros((2, 3), dtype=float32)`). A conforming implementation may add methods or attributes to dtype objects; these are not part of this specification however.
+    The default floating-point data type should be clearly defined in a conforming library's documentation.
+
+A conforming implementation of the array API standard must define a default data type for an array index (either `int32` or `int64`).
 
 .. note::
 
-    Implementations may provide others ways to specify dtypes (e.g.,
-    `zeros((2, 3), dtype='f4')`); these are not part of this specification however.
+    The default array index data type should be clearly defined in a conforming library's documentation.
 
 
 ## bool