Source code for sympy.codegen.futils

from itertools import chain
from sympy.codegen.fnodes import Module
from sympy.core.symbol import Dummy
from sympy.printing.fcode import FCodePrinter

""" This module collects utilities for rendering Fortran code. """


def render_as_module(definitions, name, declarations=(), printer_settings=None):
    """ Creates a ``Module`` instance and renders it as a string.

    This generates Fortran source code for a module with the correct ``use`` statements.

    Parameters
    ==========

    definitions : iterable
        Passed to :class:`sympy.codegen.fnodes.Module`.
    name : str
        Passed to :class:`sympy.codegen.fnodes.Module`.
    declarations : iterable
        Passed to :class:`sympy.codegen.fnodes.Module`. It will be extended with
        use statements, 'implicit none' and public list generated from ``definitions``.
    printer_settings : dict
        Passed to ``FCodePrinter`` (default: ``{'standard': 2003, 'source_format': 'free'}``).

    """
    printer_settings = printer_settings or {'standard': 2003, 'source_format': 'free'}
    printer = FCodePrinter(printer_settings)
    dummy = Dummy()
    if isinstance(definitions, Module):
        raise ValueError("This function expects to construct a module on its own.")
    mod = Module(name, chain(declarations, [dummy]), definitions)
    fstr = printer.doprint(mod)
    module_use_str = '   %s\n' % '   \n'.join(['use %s, only: %s' % (k, ', '.join(v)) for
                                                k, v in printer.module_uses.items()])
    module_use_str += '   implicit none\n'
    module_use_str += '   private\n'
    module_use_str += '   public %s\n' % ', '.join([str(node.name) for node in definitions if getattr(node, 'name', None)])
    return fstr.replace(printer.doprint(dummy), module_use_str)
    return fstr