From baf48d1987df3a06562b75e9a08936053dcb07ca Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Wed, 14 Oct 2020 01:43:13 +0200
Subject: [PATCH] Added some iso_c_bindings

---
 src/Makefile            | 15 ++++++++----
 src/README.org          | 15 ++++++------
 src/qmckl_context.c.org | 53 +++++++++++++++++++++++++++++++++++------
 3 files changed, 65 insertions(+), 18 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index aeea3d7..ee1493d 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,11 +1,18 @@
 CC=gcc
 CFLAGS=
 
+FC=gfortran
+FFLAGS=
+
 SOURCE_FILES=$(wildcard *.org)
 
-%.o: %.c.org
-	- emacs --quick --no-init-file --batch --eval "(require 'org)" --eval '(org-babel-tangle-file "$^")'
-	- $(CC) $(CFLAGS) -c $*.c -o $@
-	- rm -f $*.c $*.h
+%.c %_f.f90 %.h: %.c.org
+	emacs --quick --no-init-file --batch --eval "(require 'org)" --eval '(org-babel-tangle-file "$^")'
+
+%.o: %.c 
+	$(CC) $(CFLAGS) -c $*.c -o $*.o
+
+%.o: %.f90
+	$(FC) $(FFLAGS) -c $*.f90 -o $*.o
 
 
diff --git a/src/README.org b/src/README.org
index 2b3c741..5040596 100644
--- a/src/README.org
+++ b/src/README.org
@@ -2,15 +2,16 @@
 
 ** Introduction
 
-Source files are written in org-mode format, to provide useful comments and
-LaTex formulas close to the code. There exists multiple possibilities to convert
-org-mode files into different formats such as HTML or pdf.
+Source files are written in org-mode format, to provide useful
+comments and LaTex formulas close to the code. There exists multiple
+possibilities to convert org-mode files into different formats such as
+HTML or pdf.
 
-The code is extracted from the org files using Emacs in the =Makefile=, and
-then the produced files are compiled.
+The code is extracted from the org files using Emacs in the =Makefile=,
+and then the produced files are compiled.
 
-For a better experience, editing can be done with Emacs. Note that Emacs can
-behave like Vim when switched into ``Evil'' mode.
+For a better experience, editing can be done with Emacs. Note that
+Emacs can behave like Vim when switched into ``Evil'' mode.
 
 ** Documentation
 
diff --git a/src/qmckl_context.c.org b/src/qmckl_context.c.org
index c21cfd4..7872c22 100644
--- a/src/qmckl_context.c.org
+++ b/src/qmckl_context.c.org
@@ -1,12 +1,16 @@
 # -*- mode: org -*-
 
+This file is written in C because it is more natural to express the context in
+C than in Fortran. This file also produces the Fortran binding.
+
+
 #+BEGIN_SRC C :tangle qmckl_context.c
 #include <stdlib.h>   /* malloc */
 #include "qmckl_context.h"
 #+END_SRC
 
 * Context
-  
+
   The context variable is a handle for the state of the library, and
   is stored in the following data structure, which can't be seen
   outside of the library.
@@ -15,15 +19,15 @@
 #define QMCKL_DEFAULT_PRECISION 53
 #define QMCKL_DEFAULT_RANGE     2
 
-typedef long int qmckl_context ;
+typedef long long int qmckl_context ;
   #+END_SRC
 
 
   #+BEGIN_SRC C :tangle qmckl_context.c
 typedef struct qmckl_context_struct_ {
   struct qmckl_context_struct_ * prev;
-  int precision;  
-  int range;  
+  int precision;
+  int range;
 } qmckl_context_struct;
   #+END_SRC
 
@@ -52,7 +56,23 @@ qmckl_context qmckl_context_create() {
   return (qmckl_context) context;
 }
   #+END_SRC
-  
+
+  #+BEGIN_SRC fortran :tangle qmckl_context_f.f90
+integer(8) function qmckl_context_create()
+      use, intrinsic :: iso_c_binding
+      implicit none
+
+      interface
+         integer(c_long_long) function c_qmckl_context_create() &
+                         bind(C, name='qmckl_context_create')
+             use, intrinsic :: iso_c_binding, only : c_long_long
+         end function
+      end interface
+      
+      qmckl_context_create = c_qmckl_context_create()
+end
+  #+END_SRC
+
 
   #+BEGIN_SRC C :tangle qmckl_context.h
 qmckl_context qmckl_context_copy(qmckl_context context);
@@ -72,13 +92,32 @@ qmckl_context qmckl_context_copy(qmckl_context context) {
   old_context = (qmckl_context_struct*) context;
 
   new_context->prev      = old_context;
-  new_context->precision = old_context->precision; 
+  new_context->precision = old_context->precision;
   new_context->range     = old_context->range;
 
   return (qmckl_context) new_context;
 }
   #+END_SRC
-  
+
+
+  #+BEGIN_SRC fortran :tangle qmckl_context_f.f90
+integer(8) function qmckl_context_copy(context)
+      use, intrinsic :: iso_c_binding
+      implicit none
+      integer(8), intent(in)  :: context
+
+      interface
+         integer(c_long_long) function c_qmckl_context_copy(context) &
+                         bind(C, name='qmckl_context_copy')
+             use, intrinsic :: iso_c_binding, only : c_long_long
+             integer(c_long_long), intent(in)  :: context
+         end function
+      end interface
+      
+      qmckl_context_copy = c_qmckl_context_copy(context)
+end
+  #+END_SRC
+
 
 * Precision