Support sets as arguments to functions (pyccel#2031)

Improve the C-Python wrapper to allow passing sets as arguments. Fixes
pyccel#1663

**Commit Summary**
- Add documentation for set annotation
- Add description for C-Python API set manipulation functions
- Add support for constant set arguments to C functions
- Remove include guards from `Set_extensions.h` to allow extensions to
multiple set types
- Add a test for a function with a constant set argument

Author: EmilyBourne

CHANGELOG.md

@@ -37,6 +37,7 @@ All notable changes to this project will be documented in this file.
 -   #1689 : Add C and Fortran support for list method `append()`.
 -   #1876 : Add C support for indexing lists.
 -   #1690 : Add C support for list method `pop()`.
+-   #1663 : Add C support for sets as constant arguments.
 -   #1664 : Add C support for returning sets from functions.
 -   #2023 : Add support for iterating over a `set`.
 -   #1877 : Add C and Fortran Support for set method `pop()`.

docs/type_annotations.md

@@ -82,7 +82,15 @@ a : set[int] = {1, 2}
 b : set[bool] = {False, True}
 c : set[float] = {}
 ```
-So far sets can be declared as local variables or as results of functions.
+Sets can be declared as local variables, arguments or results of functions translated to C. An argument can be marked as constant using a string annotation or (in a module) using the `Final` qualifier:
+```python
+def f(a : 'const set[int]'):
+    pass
+
+from typing import Final
+def g(b : Final[set[bool]]):
+    pass
+```
 
 ## Dictionaries
 

pyccel/ast/cwrapper.py

@@ -1143,7 +1143,7 @@ def C_to_Python(c_object):
                         results = [FunctionDefResult(Variable(CNativeInt(), 'i'))])
 
 #-------------------------------------------------------------------
-#                          Set functions
+#                         Set functions
 #-------------------------------------------------------------------
 
 # https://docs.python.org/3/c-api/set.html#c.PySet_New
@@ -1159,6 +1159,36 @@ def C_to_Python(c_object):
                     results = [FunctionDefResult(Variable(PythonNativeInt(), 'i'))],
                     body = [])
 
+# https://docs.python.org/3/c-api/set.html#c.PySet_Check
+PySet_Check = FunctionDef(name = 'PySet_Check',
+                    arguments = [FunctionDefArgument(Variable(PyccelPyObject(), 'set', memory_handling='alias'))],
+                    results = [FunctionDefResult(Variable(CNativeInt(), 'i'))],
+                    body = [])
+
+# https://docs.python.org/3/c-api/set.html#c.PySet_Size
+PySet_Size = FunctionDef(name = 'PySet_Size',
+                    arguments = [FunctionDefArgument(Variable(PyccelPyObject(), 'set', memory_handling='alias'))],
+                    results = [FunctionDefResult(Variable(PythonNativeInt(), 'i'))],
+                    body = [])
+
+# https://docs.python.org/3/c-api/object.html#c.PyObject_GetIter
+PySet_GetIter = FunctionDef(name = 'PyObject_GetIter',
+                        body = [],
+                        arguments = [FunctionDefArgument(Variable(PyccelPyObject(), name='iter', memory_handling='alias'))],
+                        results = [FunctionDefResult(Variable(PyccelPyObject(), name='o', memory_handling='alias'))])
+
+# https://docs.python.org/3/c-api/set.html#c.PySet_Clear
+PySet_Clear = FunctionDef(name = 'PySet_Clear',
+                        body = [],
+                        arguments = [FunctionDefArgument(Variable(PyccelPyObject(), name='set', memory_handling='alias'))],
+                        results = [FunctionDefResult(Variable(PythonNativeInt(), 'i'))])
+
+# https://docs.python.org/3/c-api/iter.html#c.PyIter_Check
+PyIter_Next = FunctionDef(name = 'PyIter_Next',
+                        body = [],
+                        arguments = [FunctionDefArgument(Variable(PyccelPyObject(), name='iter', memory_handling='alias'))],
+                        results = [FunctionDefResult(Variable(PyccelPyObject(), name='o', memory_handling='alias'))])
+
 
 # Functions definitions are defined in pyccel/stdlib/cwrapper/cwrapper.c
 check_type_registry = {

pyccel/codegen/printing/ccode.py

@@ -325,6 +325,34 @@ def __init__(self, filename, prefix_module = None):
         self._current_module = None
         self._in_header = False
 
+    def sort_imports(self, imports):
+        """
+        Sort imports to avoid any errors due to bad ordering.
+
+        Sort imports. This is important so that types exist before they are used to create
+        container types. E.g. it is important that complex or inttypes be imported before
+        vec_int or vec_double_complex is declared.
+
+        Parameters
+        ----------
+        imports : list[Import]
+            A list of the imports.
+
+        Returns
+        -------
+        list[Import]
+            A sorted list of the imports.
+        """
+        import_src = [str(i.source) for i in imports]
+        stc_imports = [i for i in import_src if i.startswith('stc/')]
+        dependent_imports = [i for i in import_src if i in import_header_guard_prefix]
+        non_stc_imports = [i for i in import_src if i not in chain(stc_imports, dependent_imports)]
+        stc_imports.sort()
+        dependent_imports.sort()
+        non_stc_imports.sort()
+        sorted_imports = [imports[import_src.index(name)] for name in chain(non_stc_imports, stc_imports, dependent_imports)]
+        return sorted_imports
+
     def _format_code(self, lines):
         return self.indent_code(lines)
 
@@ -364,13 +392,16 @@ def is_c_pointer(self, a):
             return True
         if isinstance(a, FunctionCall):
             a = a.funcdef.results[0].var
-        if isinstance(getattr(a, 'dtype', None), CustomDataType) and a.is_argument:
-            return True
-
         if not isinstance(a, Variable):
             return False
-        return (a.is_alias and not isinstance(a.class_type, (HomogeneousTupleType, NumpyNDArrayType))) \
-                or a.is_optional or \
+        if isinstance(a.class_type, (HomogeneousTupleType, NumpyNDArrayType)):
+            return a.is_optional or any(a is bi for b in self._additional_args for bi in b)
+
+        if isinstance(a.class_type, (CustomDataType, HomogeneousContainerType, DictType)) \
+                and a.is_argument and not a.is_const:
+            return True
+
+        return a.is_alias or a.is_optional or \
                 any(a is bi for b in self._additional_args for bi in b)
 
     #========================== Numpy Elements ===============================#
@@ -745,7 +776,7 @@ def _print_PythonMinMax(self, expr):
             op = '<' if isinstance(expr, PythonMin) else '>'
             return f"({arg1} {op} {arg2} ? {arg1} : {arg2})"
         elif len(arg) > 2 and isinstance(arg.dtype.primitive_type, (PrimitiveFloatingPointType, PrimitiveIntegerType)):
-            key = self.get_declare_type(arg[0])
+            key = self.get_c_type(arg[0].class_type)
             self.add_import(Import('stc/common', AsName(VariableTypeAnnotation(arg.dtype), key)))
             self.add_import(Import('Common_extensions',
                                    AsName(VariableTypeAnnotation(arg.dtype), key),
@@ -851,6 +882,7 @@ def _print_ModuleHeader(self, expr):
 
         # Print imports last to be sure that all additional_imports have been collected
         imports = [*expr.module.imports, *self._additional_imports.values()]
+        imports = self.sort_imports(imports)
         imports = ''.join(self._print(i) for i in imports)
 
         self._in_header = False
@@ -2658,6 +2690,7 @@ def _print_Program(self, expr):
         decs = ''.join(self._print(Declare(v)) for v in variables)
 
         imports = [*expr.imports, *self._additional_imports.values()]
+        imports = self.sort_imports(imports)
         imports = ''.join(self._print(i) for i in imports)
 
         self.exit_scope()
@@ -2724,18 +2757,18 @@ def _print_SetPop(self, expr):
         return f'{var_type}_pop({set_var})'
 
     def _print_SetClear(self, expr):
-        var_type = self.get_declare_type(expr.set_variable)
+        var_type = self.get_c_type(expr.set_variable.class_type)
         set_var = self._print(ObjectAddress(expr.set_variable))
         return f'{var_type}_clear({set_var});\n'
 
     def _print_SetAdd(self, expr):
-        var_type = self.get_declare_type(expr.set_variable)
+        var_type = self.get_c_type(expr.set_variable.class_type)
         set_var = self._print(ObjectAddress(expr.set_variable))
         arg = self._print(expr.args[0])
         return f'{var_type}_push({set_var}, {arg});\n'
 
     def _print_SetCopy(self, expr):
-        var_type = self.get_declare_type(expr.set_variable)
+        var_type = self.get_c_type(expr.set_variable.class_type)
         set_var = self._print(expr.set_variable)
         return f'{var_type}_clone({set_var})'