DOC: Add a NEP link to all neps.

Usefull for crossreferencing and intersphinx

Here is a snippet to update it if other neps are missing it:

    In [1]: neps = !ls nep-0*
       ...: for nep in neps:
       ...:     number = nep[6:8]
       ...:     with open(nep, 'r') as f:
       ...:         data = f.read()
       ...:
       ...:     if f'.. _NEP{number}:' in data:
       ...:         continue
       ...:     with open(nep, 'w') as f:
       ...:         f.write('.. _NEP'+number+':\n')
       ...:         f.write(data)
       ...:

40 files changed, 87 insertions, 21 deletions

diff --git a/doc/neps/nep-0000.rst b/doc/neps/nep-0000.rst
index 56a332626..dcc7f4cf8 100644
--- a/doc/neps/nep-0000.rst
+++ b/doc/neps/nep-0000.rst
@@ -1,3 +1,5 @@
+.. _NEP00:
+
 ===========================
 NEP 0 — Purpose and Process
 ===========================
diff --git a/doc/neps/nep-0001-npy-format.rst b/doc/neps/nep-0001-npy-format.rst
index 4eded02ff..3a28247ab 100644
--- a/doc/neps/nep-0001-npy-format.rst
+++ b/doc/neps/nep-0001-npy-format.rst
@@ -1,3 +1,5 @@
+.. _NEP01:
+
 =============================================
 NEP 1 — A Simple File Format for NumPy Arrays
 =============================================
diff --git a/doc/neps/nep-0002-warnfix.rst b/doc/neps/nep-0002-warnfix.rst
index 207dfa3d4..dfccd5ab8 100644
--- a/doc/neps/nep-0002-warnfix.rst
+++ b/doc/neps/nep-0002-warnfix.rst
@@ -1,3 +1,5 @@
+.. _NEP02:
+
 =================================================================================
 NEP 2 — A proposal to build numpy without warning with a big set of warning flags
 =================================================================================
diff --git a/doc/neps/nep-0003-math_config_clean.rst b/doc/neps/nep-0003-math_config_clean.rst
index ebd32b124..ff5a325fc 100644
--- a/doc/neps/nep-0003-math_config_clean.rst
+++ b/doc/neps/nep-0003-math_config_clean.rst
@@ -1,3 +1,5 @@
+.. _NEP03:
+
 =====================================================
 NEP 3 — Cleaning the math configuration of numpy.core
 =====================================================
diff --git a/doc/neps/nep-0004-datetime-proposal3.rst b/doc/neps/nep-0004-datetime-proposal3.rst
index b32964e88..78b139dc5 100644
--- a/doc/neps/nep-0004-datetime-proposal3.rst
+++ b/doc/neps/nep-0004-datetime-proposal3.rst
@@ -1,3 +1,5 @@
+.. _NEP04:
+
 =========================================================================
 NEP 4 — A (third) proposal for implementing some date/time types in NumPy
 =========================================================================
diff --git a/doc/neps/nep-0005-generalized-ufuncs.rst b/doc/neps/nep-0005-generalized-ufuncs.rst
index 366e26ffd..43459a555 100644
--- a/doc/neps/nep-0005-generalized-ufuncs.rst
+++ b/doc/neps/nep-0005-generalized-ufuncs.rst
@@ -1,3 +1,5 @@
+.. _NEP05:
+
 =======================================
 NEP 5 — Generalized Universal Functions
 =======================================
diff --git a/doc/neps/nep-0006-newbugtracker.rst b/doc/neps/nep-0006-newbugtracker.rst
index 8dc7a1d8e..cb13f7882 100644
--- a/doc/neps/nep-0006-newbugtracker.rst
+++ b/doc/neps/nep-0006-newbugtracker.rst
@@ -1,3 +1,5 @@
+.. _NEP06:
+
 ===================================================
 NEP 6 — Replacing Trac with a different bug tracker
 ===================================================
diff --git a/doc/neps/nep-0007-datetime-proposal.rst b/doc/neps/nep-0007-datetime-proposal.rst
index 5547a4306..8f6c52737 100644
--- a/doc/neps/nep-0007-datetime-proposal.rst
+++ b/doc/neps/nep-0007-datetime-proposal.rst
@@ -1,3 +1,5 @@
+.. _NEP07:
+
 ==================================================================
 NEP 7 — A proposal for implementing some date/time types in NumPy
 ==================================================================
diff --git a/doc/neps/nep-0008-groupby_additions.rst b/doc/neps/nep-0008-groupby_additions.rst
index 3189fcf41..89d454914 100644
--- a/doc/neps/nep-0008-groupby_additions.rst
+++ b/doc/neps/nep-0008-groupby_additions.rst
@@ -1,3 +1,5 @@
+.. _NEP08:
+
 =============================================================
 NEP 8 —  A proposal for adding groupby functionality to NumPy
 =============================================================
diff --git a/doc/neps/nep-0009-structured_array_extensions.rst b/doc/neps/nep-0009-structured_array_extensions.rst
index 8b81a308d..cd6c3f6c3 100644
--- a/doc/neps/nep-0009-structured_array_extensions.rst
+++ b/doc/neps/nep-0009-structured_array_extensions.rst
@@ -1,3 +1,5 @@
+.. _NEP09:
+
 ===================================
 NEP 9 — Structured array extensions
 ===================================
diff --git a/doc/neps/nep-0010-new-iterator-ufunc.rst b/doc/neps/nep-0010-new-iterator-ufunc.rst
index 7a2a272f4..87617f414 100644
--- a/doc/neps/nep-0010-new-iterator-ufunc.rst
+++ b/doc/neps/nep-0010-new-iterator-ufunc.rst
@@ -1,3 +1,5 @@
+.. _NEP10:
+
 ==============================================
 NEP 10 — Optimizing Iterator/UFunc Performance
 ==============================================
diff --git a/doc/neps/nep-0011-deferred-ufunc-evaluation.rst b/doc/neps/nep-0011-deferred-ufunc-evaluation.rst
index a7143c6ee..c40ca56d7 100644
--- a/doc/neps/nep-0011-deferred-ufunc-evaluation.rst
+++ b/doc/neps/nep-0011-deferred-ufunc-evaluation.rst
@@ -1,3 +1,5 @@
+.. _NEP11:
+
 ==================================
 NEP 11 — Deferred UFunc Evaluation
 ==================================
diff --git a/doc/neps/nep-0012-missing-data.rst b/doc/neps/nep-0012-missing-data.rst
index f7026b4be..0adcea69a 100644
--- a/doc/neps/nep-0012-missing-data.rst
+++ b/doc/neps/nep-0012-missing-data.rst
@@ -1,3 +1,5 @@
+.. _NEP12:
+
 ============================================
 NEP 12 — Missing Data Functionality in NumPy
 ============================================
diff --git a/doc/neps/nep-0013-ufunc-overrides.rst b/doc/neps/nep-0013-ufunc-overrides.rst
index 0888c7559..5c28e9446 100644
--- a/doc/neps/nep-0013-ufunc-overrides.rst
+++ b/doc/neps/nep-0013-ufunc-overrides.rst
@@ -1,3 +1,5 @@
+.. _NEP13:
+
 ==========================================
 NEP 13 — A Mechanism for Overriding Ufuncs
 ==========================================
diff --git a/doc/neps/nep-0014-dropping-python2.7-proposal.rst b/doc/neps/nep-0014-dropping-python2.7-proposal.rst
index 3adf3b407..dfc09d254 100644
--- a/doc/neps/nep-0014-dropping-python2.7-proposal.rst
+++ b/doc/neps/nep-0014-dropping-python2.7-proposal.rst
@@ -1,3 +1,5 @@
+.. _NEP14:
+
 =============================================
 NEP 14 — Plan for dropping Python 2.7 support
 =============================================
diff --git a/doc/neps/nep-0015-merge-multiarray-umath.rst b/doc/neps/nep-0015-merge-multiarray-umath.rst
index 576a21e23..1efceb957 100644
--- a/doc/neps/nep-0015-merge-multiarray-umath.rst
+++ b/doc/neps/nep-0015-merge-multiarray-umath.rst
@@ -1,3 +1,5 @@
+.. _NEP15:
+
 =====================================
 NEP 15 — Merging multiarray and umath
 =====================================
diff --git a/doc/neps/nep-0016-abstract-array.rst b/doc/neps/nep-0016-abstract-array.rst
index 7551b11b9..63ad600e9 100644
--- a/doc/neps/nep-0016-abstract-array.rst
+++ b/doc/neps/nep-0016-abstract-array.rst
@@ -1,3 +1,5 @@
+.. _NEP16:
+
 =============================================================
 NEP 16 — An abstract base class for identifying "duck arrays"
 =============================================================
diff --git a/doc/neps/nep-0016-benchmark.py b/doc/neps/nep-0016-benchmark.py
index ec8e44726..af6059114 100644
--- a/doc/neps/nep-0016-benchmark.py
+++ b/doc/neps/nep-0016-benchmark.py
@@ -1,3 +1,5 @@
+.. _NEP16:
+
 import perf
 import abc
 import numpy as np
diff --git a/doc/neps/nep-0017-split-out-maskedarray.rst b/doc/neps/nep-0017-split-out-maskedarray.rst
index 7ef949763..151c5ad1a 100644
--- a/doc/neps/nep-0017-split-out-maskedarray.rst
+++ b/doc/neps/nep-0017-split-out-maskedarray.rst
@@ -1,3 +1,5 @@
+.. _NEP17:
+
 ================================
 NEP 17 — Split Out Masked Arrays
 ================================
diff --git a/doc/neps/nep-0018-array-function-protocol.rst b/doc/neps/nep-0018-array-function-protocol.rst
index 3147d8cee..0dcb0ff7e 100644
--- a/doc/neps/nep-0018-array-function-protocol.rst
+++ b/doc/neps/nep-0018-array-function-protocol.rst
@@ -1,3 +1,5 @@
+.. _NEP18:
+
 ====================================================================
 NEP 18 — A dispatch mechanism for NumPy's high level array functions
 ====================================================================
diff --git a/doc/neps/nep-0019-rng-policy.rst b/doc/neps/nep-0019-rng-policy.rst
index 4f766fa2d..077997f43 100644
--- a/doc/neps/nep-0019-rng-policy.rst
+++ b/doc/neps/nep-0019-rng-policy.rst
@@ -1,3 +1,5 @@
+.. _NEP19:
+
 =======================================
 NEP 19 — Random Number Generator Policy
 =======================================
diff --git a/doc/neps/nep-0020-gufunc-signature-enhancement.rst b/doc/neps/nep-0020-gufunc-signature-enhancement.rst
index a7a992cf1..90ed930b4 100644
--- a/doc/neps/nep-0020-gufunc-signature-enhancement.rst
+++ b/doc/neps/nep-0020-gufunc-signature-enhancement.rst
@@ -1,3 +1,5 @@
+.. _NEP20:
+
 ===============================================================
 NEP 20 — Expansion of Generalized Universal Function Signatures
 ===============================================================
diff --git a/doc/neps/nep-0021-advanced-indexing.rst b/doc/neps/nep-0021-advanced-indexing.rst
index 0d20d680f..7751d309b 100644
--- a/doc/neps/nep-0021-advanced-indexing.rst
+++ b/doc/neps/nep-0021-advanced-indexing.rst
@@ -1,3 +1,5 @@
+.. _NEP21:
+
 ==================================================
 NEP 21 — Simplified and explicit advanced indexing
 ==================================================
diff --git a/doc/neps/nep-0022-ndarray-duck-typing-overview.rst b/doc/neps/nep-0022-ndarray-duck-typing-overview.rst
index 9ece915a7..47b81d9e7 100644
--- a/doc/neps/nep-0022-ndarray-duck-typing-overview.rst
+++ b/doc/neps/nep-0022-ndarray-duck-typing-overview.rst
@@ -1,3 +1,5 @@
+.. _NEP22:
+
 ===========================================================
 NEP 22 — Duck typing for NumPy arrays – high level overview
 ===========================================================
diff --git a/doc/neps/nep-0023-backwards-compatibility.rst b/doc/neps/nep-0023-backwards-compatibility.rst
index 92974ad6e..158f46273 100644
--- a/doc/neps/nep-0023-backwards-compatibility.rst
+++ b/doc/neps/nep-0023-backwards-compatibility.rst
@@ -1,3 +1,5 @@
+.. _NEP23:
+
 =======================================================
 NEP 23 — Backwards compatibility and deprecation policy
 =======================================================
diff --git a/doc/neps/nep-0024-missing-data-2.rst b/doc/neps/nep-0024-missing-data-2.rst
index f4414e0a0..8e63629f3 100644
--- a/doc/neps/nep-0024-missing-data-2.rst
+++ b/doc/neps/nep-0024-missing-data-2.rst
@@ -1,3 +1,5 @@
+.. _NEP24:
+
 =============================================================
 NEP 24 — Missing Data Functionality - Alternative 1 to NEP 12
 =============================================================
diff --git a/doc/neps/nep-0025-missing-data-3.rst b/doc/neps/nep-0025-missing-data-3.rst
index 6343759e8..19be3cf1e 100644
--- a/doc/neps/nep-0025-missing-data-3.rst
+++ b/doc/neps/nep-0025-missing-data-3.rst
@@ -1,3 +1,5 @@
+.. _NEP25:
+
 ======================================
 NEP 25 — NA support via special dtypes
 ======================================
diff --git a/doc/neps/nep-0026-missing-data-summary.rst b/doc/neps/nep-0026-missing-data-summary.rst
index 78fe999df..f25ce9b91 100644
--- a/doc/neps/nep-0026-missing-data-summary.rst
+++ b/doc/neps/nep-0026-missing-data-summary.rst
@@ -1,3 +1,5 @@
+.. _NEP26:
+
 ====================================================
 NEP 26 — Summary of Missing Data NEPs and discussion
 ====================================================
@@ -8,7 +10,7 @@ NEP 26 — Summary of Missing Data NEPs and discussion
 :Created: 2012-04-22
 
 *Context*: this NEP was written as summary of the large number of discussions
-and proposals (`NEP 12`_, `NEP 24`_, `NEP 25`_), regarding missing data
+and proposals (:ref:`NEP12`, :ref:`NEP24`, :ref:`NEP25`), regarding missing data
 functionality.
 
 The debate about how NumPy should handle missing data, a subject with
@@ -349,7 +351,7 @@ dtypes can arrange for certain bitpatterns to be given NA semantics.
 One option is to copy numpy.ma closely, but with a more optimized
 implementation. (Or to simply optimize the existing implementation.)
 
-One option is that described in `NEP 12`_, for which an implementation
+One option is that described in `NEP12`, for which an implementation
 of mask-based missing data exists. This system is roughly:
 
 * There is both bitpattern and mask-based missing data, and both
@@ -364,7 +366,7 @@ of mask-based missing data exists. This system is roughly:
   a bitpattern NA to an array which supports both requires accessing
   the data by "peeking under the mask".
 
-Another option is that described in `NEP 24`_, which is to implement
+Another option is that described in `NEP24`, which is to implement
 bitpattern dtypes with NA semantics for the "statistical missing data"
 use case, and to also implement a totally independent API for masked
 arrays with ignore semantics and all mask manipulation done explicitly
@@ -704,14 +706,14 @@ risk of reducing developer contribution.
 References and Footnotes
 ------------------------
 
-`NEP 12`_ describes Mark's NA-semantics/mask implementation/view based mask
+:ref:`NEP12` describes Mark's NA-semantics/mask implementation/view based mask
 handling API.
 
-`NEP 24`_ ("the alterNEP") was Nathaniel's initial attempt at separating MISSING
+:ref:`NEP24` ("the alterNEP") was Nathaniel's initial attempt at separating MISSING
 and IGNORED handling into bit-patterns versus masks, though there's a bunch
 he would change about the proposal at this point.
 
-`NEP 25`_ ("miniNEP 2") was a later attempt by Nathaniel to sketch out an
+:ref:`NEP25` ("miniNEP 2") was a later attempt by Nathaniel to sketch out an
 implementation strategy for NA dtypes.
 
 A further discussion overview page can be found at:
@@ -722,9 +724,3 @@ Copyright
 ---------
 
 This document has been placed in the public domain.
-
-.. _NEP 12: http://www.numpy.org/neps/nep-0012-missing-data.html
-
-.. _NEP 24: http://www.numpy.org/neps/nep-0024-missing-data-2.html
-
-.. _NEP 25: http://www.numpy.org/neps/nep-0025-missing-data-3.html
diff --git a/doc/neps/nep-0027-zero-rank-arrarys.rst b/doc/neps/nep-0027-zero-rank-arrarys.rst
index 430397235..2d152234c 100644
--- a/doc/neps/nep-0027-zero-rank-arrarys.rst
+++ b/doc/neps/nep-0027-zero-rank-arrarys.rst
@@ -1,3 +1,5 @@
+.. _NEP27:
+
 =========================
 NEP 27 — Zero Rank Arrays
 =========================
diff --git a/doc/neps/nep-0028-website-redesign.rst b/doc/neps/nep-0028-website-redesign.rst
index 68f25ad4d..e27da91c6 100644
--- a/doc/neps/nep-0028-website-redesign.rst
+++ b/doc/neps/nep-0028-website-redesign.rst
@@ -1,3 +1,5 @@
+.. _NEP28:
+
 ===================================
 NEP 28 — numpy.org website redesign
 ===================================
diff --git a/doc/neps/nep-0029-deprecation_policy.rst b/doc/neps/nep-0029-deprecation_policy.rst
index dbead1b9b..9b6022a81 100644
--- a/doc/neps/nep-0029-deprecation_policy.rst
+++ b/doc/neps/nep-0029-deprecation_policy.rst
@@ -1,4 +1,4 @@
-.. _NEP29:
+.. _NEP0029:
 
 ==================================================================================
 NEP 29 — Recommend Python and Numpy version support as a community policy standard
diff --git a/doc/neps/nep-0030-duck-array-protocol.rst b/doc/neps/nep-0030-duck-array-protocol.rst
index 6b636f9b0..11a297132 100644
--- a/doc/neps/nep-0030-duck-array-protocol.rst
+++ b/doc/neps/nep-0030-duck-array-protocol.rst
@@ -1,3 +1,5 @@
+.. _NEP30:
+
 ======================================================
 NEP 30 — Duck Typing for NumPy Arrays - Implementation
 ======================================================
diff --git a/doc/neps/nep-0031-uarray.rst b/doc/neps/nep-0031-uarray.rst
index 737d2b456..47d4bdd37 100644
--- a/doc/neps/nep-0031-uarray.rst
+++ b/doc/neps/nep-0031-uarray.rst
@@ -1,3 +1,5 @@
+.. _NEP31:
+
 ============================================================
 NEP 31 — Context-local and global overrides of the NumPy API
 ============================================================
diff --git a/doc/neps/nep-0032-remove-financial-functions.rst b/doc/neps/nep-0032-remove-financial-functions.rst
index a78b11fea..1c3722f46 100644
--- a/doc/neps/nep-0032-remove-financial-functions.rst
+++ b/doc/neps/nep-0032-remove-financial-functions.rst
@@ -1,3 +1,5 @@
+.. _NEP32:
+
 ==================================================
 NEP 32 — Remove the financial functions from NumPy
 ==================================================
diff --git a/doc/neps/nep-0034-infer-dtype-is-object.rst b/doc/neps/nep-0034-infer-dtype-is-object.rst
index 2e0ae46f4..a424ab4a3 100644
--- a/doc/neps/nep-0034-infer-dtype-is-object.rst
+++ b/doc/neps/nep-0034-infer-dtype-is-object.rst
@@ -1,3 +1,5 @@
+.. _NEP34:
+
 ===========================================================
 NEP 34 — Disallow inferring ``dtype=object`` from sequences
 ===========================================================
diff --git a/doc/neps/nep-0035-array-creation-dispatch-with-array-function.rst b/doc/neps/nep-0035-array-creation-dispatch-with-array-function.rst
index 884dbe0cc..2d7539952 100644
--- a/doc/neps/nep-0035-array-creation-dispatch-with-array-function.rst
+++ b/doc/neps/nep-0035-array-creation-dispatch-with-array-function.rst
@@ -1,3 +1,5 @@
+.. _NEP35:
+
 ===========================================================
 NEP 35 — Array Creation Dispatching With __array_function__
 ===========================================================
diff --git a/doc/neps/nep-0037-array-module.rst b/doc/neps/nep-0037-array-module.rst
index d789ef0de..1e868324d 100644
--- a/doc/neps/nep-0037-array-module.rst
+++ b/doc/neps/nep-0037-array-module.rst
@@ -1,3 +1,5 @@
+.. _NEP37:
+
 ===================================================
 NEP 37 — A dispatch protocol for NumPy-like modules
 ===================================================
diff --git a/doc/neps/nep-0038-SIMD-optimizations.rst b/doc/neps/nep-0038-SIMD-optimizations.rst
index ab16868e4..396ba1371 100644
--- a/doc/neps/nep-0038-SIMD-optimizations.rst
+++ b/doc/neps/nep-0038-SIMD-optimizations.rst
@@ -1,3 +1,5 @@
+.. _NEP38:
+
 =============================================================
 NEP 38 — Using SIMD optimization instructions for performance
 =============================================================
diff --git a/doc/neps/nep-0044-restructuring-numpy-docs.rst b/doc/neps/nep-0044-restructuring-numpy-docs.rst
index 87da4edb0..229856547 100644
--- a/doc/neps/nep-0044-restructuring-numpy-docs.rst
+++ b/doc/neps/nep-0044-restructuring-numpy-docs.rst
@@ -1,3 +1,5 @@
+.. _NEP44:
+
 ===================================================
 NEP 44 — Restructuring the NumPy Documentation
 ===================================================
diff --git a/doc/neps/roadmap.rst b/doc/neps/roadmap.rst
index c5abc5f25..3780499a0 100644
--- a/doc/neps/roadmap.rst
+++ b/doc/neps/roadmap.rst
@@ -17,10 +17,10 @@ may include (among other things) interoperability protocols, better duck typing
 support and ndarray subclass handling.
 
 - The ``__array_function__`` protocol is currently experimental and needs to be
-  matured. See `NEP 18`_ for details.
+  matured. See  :ref`NEP18` for details.
 - New protocols for overriding other functionality in NumPy may be needed.
 - Array duck typing, or handling "duck arrays", needs improvements.  See
-  `NEP 22`_ for details.
+  :ref:`NEP22` for details.
 
 Extensibility
 -------------
@@ -71,13 +71,13 @@ Random number generation policy & rewrite
 -----------------------------------------
 
 A new random number generation framework with higher performance generators is
-close to completion, see `NEP 19`_ and `PR 13163`_.
+close to completion, see :ref:`NEP19` and `PR 13163`_.
 
 Indexing
 --------
 
 We intend to add new indexing modes for "vectorized indexing" and "outer indexing",
-see `NEP 21`_.
+see :ref:`NEP21`.
 
 Continuous Integration
 ----------------------
@@ -105,10 +105,6 @@ Other functionality
 - Deprecate ``np.matrix`` (very slowly)
 
 
-.. _`NEP 19`: https://www.numpy.org/neps/nep-0019-rng-policy.html
-.. _`NEP 22`: http://www.numpy.org/neps/nep-0022-ndarray-duck-typing-overview.html
-.. _`NEP 18`: https://www.numpy.org/neps/nep-0018-array-function-protocol.html
 .. _implementation: https://gist.github.com/shoyer/1f0a308a06cd96df20879a1ddb8f0006
 .. _`reference implementation`: https://github.com/bashtage/randomgen
-.. _`NEP 21`: https://www.numpy.org/neps/nep-0021-advanced-indexing.html
 .. _`PR 13163`: https://github.com/numpy/numpy/pull/13163