Allow transpilers it declare main signature

Also integrates c++ main handling with PythonMainRewriter.
MiguelMarcelino · Jun 27, 2021 · eae0901 · eae0901
1 parent ef48ac2
commit eae0901
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Showing 11 changed files with 28 additions and 26 deletions.
diff --git a/py2many/cli.py b/py2many/cli.py
@@ -116,7 +116,7 @@ def _transpile(
     language = transpiler.NAME
     generic_rewriters = [
         ComplexDestructuringRewriter(language),
-        PythonMainRewriter(language),
+        PythonMainRewriter(settings.transpiler._main_signature_arg_names),
         FStringJoinRewriter(language),
         DocStringToCommentRewriter(language),
         WithToBlockTransformer(language),

diff --git a/py2many/clike.py b/py2many/clike.py
@@ -123,6 +123,7 @@ def __init__(self):
         self._container_type_map = {}
         self._default_type = _AUTO
         self._statement_separator = ";"
+        self._main_signature_arg_names = []
         self._extension = False
         self._ignored_module_set = IGNORED_MODULE_SET.copy()
         self._module = None

diff --git a/py2many/rewriters.py b/py2many/rewriters.py
@@ -129,7 +129,8 @@ def rename(scope, old_name, new_name):
 
 
 class PythonMainRewriter(ast.NodeTransformer):
-    def __init__(self, language):
+    def __init__(self, main_signature_arg_names):
+        self.main_signature_arg_names = set(main_signature_arg_names)
         super().__init__()
 
     def visit_If(self, node):
@@ -145,10 +146,17 @@ def visit_If(self, node):
             if hasattr(node, "scopes") and len(node.scopes) > 1:
                 rename(node.scopes[-2], "main", "main_func")
             # ast.parse produces a Module object that needs to be destructured
-            ret = ast.parse("def main(argc: int, argv: List[str]): True").body[0]
+            if self.main_signature_arg_names == {"argc", "argv"}:
+                ret = ast.parse(
+                    "def main(argc: int, argv: List[str]) -> int: True"
+                ).body[0]
+            elif self.main_signature_arg_names == {"argv"}:
+                ret = ast.parse("def main(argv: List[str]): True").body[0]
+            else:
+                ret = ast.parse("def main(): True").body[0]
             ret.lineno = node.lineno
             ret.body = node.body
-            # So backends know to insert argc, argv etc
+            # So backends know to handle argc, argv etc
             ret.python_main = True
             return ret
         return node

diff --git a/pycpp/tests/test_transpiler.py b/pycpp/tests/test_transpiler.py
@@ -81,8 +81,10 @@ def test_print_program_args():
         'if __name__ == "__main__":', "    for arg in sys.argv:", "       print(arg)"
     )
     cpp = transpile(source)
+    # Note the args and return type are missing here as this `transpile` wrapper
+    # is not the main py2many wrapper, and notably doesnt use PythonMainRewriter.
     assert cpp == parse(
-        "int main(int argc, char ** argv) {",
+        "void main() {",
         "pycpp::sys::argv = std::vector<std::string>(argv, argv + argc);",
         "for(auto arg : pycpp::sys::argv) {",
         "std::cout << arg;",

diff --git a/pycpp/transpiler.py b/pycpp/transpiler.py
@@ -134,6 +134,7 @@ def __init__(self, extension: bool = False, no_prologue: bool = False):
         self._small_usings_map = SMALL_USINGS_MAP
         self._func_dispatch_table = FUNC_DISPATCH_TABLE
         self._attr_dispatch_table = ATTR_DISPATCH_TABLE
+        self._main_signature_arg_names = ["argc", "argv"]
 
     def usings(self):
         usings = sorted(list(set(self._usings)))
@@ -170,6 +171,7 @@ def visit_FunctionDef(self, node):
         ):
             return generate_catch_test_case(node, body)
 
+        is_python_main = getattr(node, "python_main", False)
         typenames, args = self.visit(node.args)
 
         args_list = []
@@ -187,17 +189,21 @@ def visit_FunctionDef(self, node):
                 typename = "T{0}".format(index)
                 typedecls.append(typename)
                 index += 1
+            if is_python_main and arg in ["argv"]:
+                typename = "char **"
             args_list.append(f"{typename} {arg}")
 
         template = "inline "
         if len(typedecls) > 0:
             typedecls_str = ", ".join([f"typename {t}" for t in typedecls])
             template = f"template <{typedecls_str}>"
 
-        return_type = "auto"
-        if node.name == "main":
+        if is_python_main:
+            body = (
+                "pycpp::sys::argv = std::vector<std::string>(argv, argv + argc);\n"
+                + body
+            )
             template = ""
-            return_type = "int"
 
         if not is_void_function(node):
             if node.returns:
@@ -210,14 +216,7 @@ def visit_FunctionDef(self, node):
 
         args = ", ".join(args_list)
         funcdef = f"{template}{return_type} {node.name}({args}) {{"
-        if getattr(node, "python_main", False):
-            funcdef = "\n".join(
-                [
-                    "int main(int argc, char ** argv) {",
-                    "pycpp::sys::argv = "
-                    "std::vector<std::string>(argv, argv + argc);",
-                ]
-            )
+
         return funcdef + "\n" + body + "}\n"
 
     def visit_Attribute(self, node):

diff --git a/pydart/transpiler.py b/pydart/transpiler.py
@@ -56,6 +56,7 @@ def __init__(self):
         self._small_usings_map = SMALL_USINGS_MAP
         self._func_dispatch_table = FUNC_DISPATCH_TABLE
         self._attr_dispatch_table = ATTR_DISPATCH_TABLE
+        self._main_signature_arg_names = ["argv"]
 
     def _get_temp(self):
         self._temp += 1

diff --git a/pygo/transpiler.py b/pygo/transpiler.py
@@ -166,16 +166,12 @@ def visit_FunctionDef(self, node):
         if len(typenames) and typenames[0] == None and hasattr(node, "self_type"):
             typenames[0] = node.self_type
 
-        is_python_main = getattr(node, "python_main", False)
-
         args_list = []
         typedecls = []
         index = 0
         for i in range(len(args)):
             typename = typenames[i]
             arg = args[i]
-            if is_python_main and arg in ["argc", "argv"]:
-                continue
 
             if typename == "T":
                 typename = "T{0} any".format(index)

diff --git a/pyjl/transpiler.py b/pyjl/transpiler.py
@@ -95,8 +95,6 @@ def visit_FunctionDef(self, node):
         for i in range(len(args)):
             typename = typenames[i]
             arg = args[i]
-            if is_python_main and arg in ["argc", "argv"]:
-                continue
             if typename == "T":
                 typename = "T{0}".format(index)
                 typedecls.append(typename)

diff --git a/pykt/transpiler.py b/pykt/transpiler.py
@@ -100,6 +100,7 @@ def __init__(self):
         super().__init__()
         self._default_type = ""
         self._container_type_map = self.CONTAINER_TYPE_MAP
+        self._main_signature_arg_names = ["argv"]
 
     def usings(self):
         usings = sorted(list(set(self._usings)))

diff --git a/pynim/transpiler.py b/pynim/transpiler.py
@@ -88,8 +88,6 @@ def visit_FunctionDef(self, node):
         for i in range(len(args)):
             typename = typenames[i]
             arg = args[i]
-            if is_python_main and arg in ["argc", "argv"]:
-                continue
 
             args_list.append(f"{arg}: {typename}".format(arg, typename))
 

diff --git a/pyrs/transpiler.py b/pyrs/transpiler.py
@@ -205,8 +205,6 @@ def visit_FunctionDef(self, node, async_prefix=""):
         for i in range(len(args)):
             typename = typenames[i]
             arg = args[i]
-            if is_python_main and arg in ["argc", "argv"]:
-                continue
 
             if typename == "T":
                 typename = "T{0}".format(index)