# -*- mode: org -*-

* Function to get the value of a property.
#+NAME: get_value
#+begin_src elisp :var key="Type"
(setq x (org-property-values key))
(pop x)
#+end_src

#+RESULTS: get_value

* Table of function arguments

  #+NAME: test
  | qmckl_context | context   | in  | Global state                                  |
  | char          | transa    | in  | Array ~A~ is ~'N'~: Normal, ~'T'~: Transposed |
  | char          | transb    | in  | Array ~B~ is ~'N'~: Normal, ~'T'~: Transposed |
  | int64_t       | m         | in  | Number of points in the first set             |
  | int64_t       | n         | in  | Number of points in the second set            |
  | double        | A[3][lda] | in  | Array containing the $m \times 3$ matrix $A$  |
  | int64_t       | lda       | in  | Leading dimension of array ~A~                |
  | double        | B[3][ldb] | in  | Array containing the $n \times 3$ matrix $B$  |
  | int64_t       | ldb       | in  | Leading dimension of array ~B~                |
  | double        | C[n][ldc] | out | Array containing the $m \times n$ matrix $C$  |
  | int64_t       | ldc       | in  | Leading dimension of array ~C~                |


** Fortran-C type conversions

   #+NAME:f_of_c
   #+BEGIN_SRC python :var table=test :var rettyp="integer" :var fname=[] :results value :noweb yes :wrap "src f90 :tangle (eval f) :comments org :exports none"
f_of_c_d = { '' : ''
     , 'qmckl_context'   : 'integer (qmckl_context)'
     , 'qmckl_exit_code' : 'integer (qmckl_exit_code)'
     , 'int32_t'         : 'integer (c_int32_t)'
     , 'int64_t'         : 'integer (c_int64_t)'
     , 'float'           : 'real    (c_float  )'
     , 'double'          : 'real    (c_double )'
     , 'char'            : 'character'
 }
   #+END_SRC

   #+NAME:c_of_f
   #+BEGIN_SRC python :var table=test :var rettyp="integer" :var fname=[] :results value :noweb yes :wrap "src f90 :tangle (eval f) :comments org :exports none"
ctypeid_d = { '' : ''
     , 'qmckl_context'   : 'integer (qmckl_context)'
     , 'qmckl_exit_code' : 'integer (qmckl_exit_code)'
     , 'integer'         : 'integer(c_int32_t)'
     , 'integer*8'       : 'integer(c_int64_t)'
     , 'real'            : 'real(c_float)'
     , 'real*8'          : 'real(c_double)'
     , 'character'       : 'character(c_char)'
 }
   #+END_SRC

** Parse the table

   #+NAME: parse_table
   #+BEGIN_SRC python :results none :noweb yes :exports none
def parse_table(table):
    result = []

    for line in table:
        d = { "c_type"  : line[0],
              "inout"   : line[2].lower(),
              "name"    : line[1],
              "comment" : line[3] }

        # Handle inout
        if d["inout"] in ["input", "in"]:
            d["inout"] == "in"
        elif d["inout"] in ["output", "out"]:
            d["inout"] == "out"
        elif d["inout"] in ["input/output", "inout"]:
            d["inout"] == "inout"

        # Find dimensions
        dims = d["name"].split('[')
        d["rank"] = len(dims) - 1
        if d["rank"] == 0:
            d["dims"] = []
        else:
            d["name"] = d["name"].split('[')[0].strip()
            d["dims"] = [ x.replace(']','').strip() for x in dims[1:] ]

        result.append(d)

    return result
   #+END_SRC

** Generates a C header

   #+NAME: generate_c_header
   #+BEGIN_SRC python :var table=[] :var rettyp=[] :var fname=[] :results drawer :noweb yes :wrap "src c :tangle (eval h_func) :comments org"
<<parse_table>>

results = []
for d in parse_table(table):
    name = d["name"]
    c_type = d["c_type"]

    # Add star for arrays
    if d["rank"] > 0:
        c_type += "*"

    # Only inputs are const
    if d["inout"] == "in":
        const = "const"
    else:
        const = "     "

    results += [ f"      {const} {c_type} {name}" ]

results=',\n'.join(results)
template = f"""{rettyp} {fname} (
{results} ); """
return template

   #+END_SRC

   #+RESULTS: generate_c_header
   #+begin_src c :tangle (eval h_func) :comments org
   [] [] (
    );
   #+end_src

** Generates a C interface to the Fortran function

   #+NAME: generate_c_interface
   #+BEGIN_SRC python :var table=[]   :var rettyp="integer" :var fname=[] :results value :noweb yes :wrap "src f90 :tangle (eval f) :comments org :exports none"
<<c_of_f>>
<<f_of_c>>
<<parse_table>>
d = parse_table(table)

args = ", ".join([ x["name"] for x in d ])

rettyp_c = ctypeid_d[rettyp.lower()]

results = [ f"{rettyp_c} function {fname} &"
, f"    ({args}) &"
,  "    bind(C) result(info)"
,  ""
,  "  use, intrinsic :: iso_c_binding"
,  "  import"
,  "  implicit none"
,  ""
]

for d in parse_table(table):
    f_type = f_of_c_d[d["c_type"]]
    inout  = "intent("+d["inout"]+")"
    name = d["name"]

    # Input scalars are passed by value
    if d["rank"] == 0 and inout == "in":
        value = ", value"
    else:
        value = "       "

    # Append dimensions to the name
    if d["rank"] == 0:
        dims = ""
    else:
        d["dims"].reverse()
        dims = "(" + ",".join(d["dims"]) + ")"

    results += [ f"  {f_type:20}, {inout:12}{value} :: {name}{dims}" ]

results += [ ""
, f"  {rettyp_c}, external :: {fname}_f"
, f"  info = {fname}_f &"
, f"         ({args})"
,  ""
, f"end function {fname}"
]
results='\n'.join(results)
return results
   #+END_SRC


** Generates a Fortran interface to the C function

   #+NAME: generate_f_interface
   #+BEGIN_SRC python :var table=test :var rettyp="integer" :var fname=[] :results value :noweb yes :wrap "src f90 :tangle (eval fh) :comments org :exports none"
<<c_of_f>>
<<f_of_c>>
<<parse_table>>
d = parse_table(table)

args = ", ".join([ x["name"] for x in d ])

rettyp_c = ctypeid_d[rettyp.lower()]

results = [ f"interface"
, f"  {rettyp_c} function {fname} &"
, f"      ({args}) &"
,  "      bind(C)"
,  "    use, intrinsic :: iso_c_binding"
,  "    import"
,  "    implicit none"
,  ""
]

for d in parse_table(table):
    f_type = f_of_c_d[d["c_type"]]
    inout  = "intent("+d["inout"]+")"
    name = d["name"]

    # Input scalars are passed by value
    if d["rank"] == 0 and inout == "in":
        value = ", value"
    else:
        value = "       "

    # Append dimensions to the name
    if d["rank"] == 0:
        dims = ""
    else:
        d["dims"].reverse()
        dims = "(" + ",".join(d["dims"]) + ")"

    results += [ f"    {f_type:20}, {inout:12}{value} :: {name}{dims}" ]

results += [ ""
, f"  end function {fname}"
, f"end interface"
]
results='\n'.join(results)
return results
   #+END_SRC

   #+RESULTS: generate_c_interface
   #+begin_src f90 :tangle (eval f) :comments org :exports none
   #+end_src