Merge pull request #573 from boriel/feature/optional_parameters

feat: allow optional parameters!

Author: boriel

setup.py

@@ -2,59 +2,56 @@
 import pathlib
 from setuptools import setup
 
-packages = [
-    'src'
-]
+packages = ["src"]
 
 # The directory containing this file
 HERE = pathlib.Path(__file__).parent
 
 # The text of the README file
 README = (HERE / "README.md").read_text()
 
-package_data = {'': ['*'], 'arch.zx48k.peephole': ['opts/*']}
+package_data = {"": ["*"], "arch.zx48k.peephole": ["opts/*"]}
 
 entry_points = {
-    'console_scripts': ['zxb = src.libzxbc.zxb:main',
-                        'zxbasm = src.libzxbasm.zxbasm:main',
-                        'zxbc = src.libzxbc.zxb:main',
-                        'zxbpp = src.libzxbpp.zxbpp:entry_point']
+    "console_scripts": [
+        "zxb = src.libzxbc.zxb:main",
+        "zxbasm = src.libzxbasm.zxbasm:main",
+        "zxbc = src.libzxbc.zxb:main",
+        "zxbpp = src.libzxbpp.zxbpp:entry_point",
+    ]
 }
 
 setup_kwargs = {
-    'name': 'zxbasic',
-    'version': '1.15.2',
-    'description': "Boriel's ZX BASIC Compiler",
-    'classifiers': [
+    "name": "zxbasic",
+    "version": "1.15.2",
+    "description": "Boriel's ZX BASIC Compiler",
+    "classifiers": [
         # How mature is this project? Common values are
         #   3 - Alpha
         #   4 - Beta
         #   5 - Production/Stable
-        'Development Status :: 5 - Production/Stable',
-
+        "Development Status :: 5 - Production/Stable",
         # Indicate who your project is intended for
-        'Intended Audience :: Developers',
-        'Topic :: Software Development :: Build Tools',
-
+        "Intended Audience :: Developers",
+        "Topic :: Software Development :: Build Tools",
         # Pick your license as you wish (should match "license" above)
-        'License :: OSI Approved :: GNU Affero General Public License v3',
-
+        "License :: OSI Approved :: GNU Affero General Public License v3",
         # Specify the Python versions you support here. In particular, ensure
         # that you indicate whether you support Python 2, Python 3 or both.
-        'Programming Language :: Python :: 3.6',
-        'Programming Language :: Python :: 3.8',
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.8",
     ],
-    'long_description_content_type': "text/markdown",
-    'long_description': README,
-    'author': 'Jose Rodriguez',
-    'author_email': 'boriel@gmail.com',
-    'maintainer': None,
-    'maintainer_email': None,
-    'url': 'http://zxbasic.net',
-    'packages': packages,
-    'package_data': package_data,
-    'entry_points': entry_points,
-    'python_requires': '>=3.6,<4.0',
+    "long_description_content_type": "text/markdown",
+    "long_description": README,
+    "author": "Jose Rodriguez",
+    "author_email": "boriel@gmail.com",
+    "maintainer": None,
+    "maintainer_email": None,
+    "url": "http://zxbasic.net",
+    "packages": packages,
+    "package_data": package_data,
+    "entry_points": entry_points,
+    "python_requires": ">=3.6,<4.0",
 }
 
 setup(**setup_kwargs)

src/api/check.py

@@ -112,6 +112,12 @@ def check_call_arguments(lineno: int, id_: str, args):
 
     entry = global_.SYMBOL_TABLE.get_entry(id_)
 
+    if len(args) < len(entry.params):  # try filling default params
+        for param in entry.params[len(args) :]:
+            if param.default_value is None:
+                break
+            symbols.ARGLIST.make_node(args, symbols.ARGUMENT(param.default_value, lineno=lineno, byref=False))
+
     if len(args) != len(entry.params):
         c = "s" if len(entry.params) != 1 else ""
         errmsg.error(

src/api/errmsg.py

@@ -303,6 +303,13 @@ def syntax_error_cannot_initialize_array_of_type(lineno: int, type_name: str):
     error(lineno, f"Cannot initialize array of type {type_name}")
 
 
+# ----------------------------------------
+#  Cannot define a default array argument
+# ----------------------------------------
+def syntax_error_cannot_define_default_array_argument(lineno: int):
+    error(lineno, "Cannot define default array argument")
+
+
 # ----------------------------------------
 #  Error, ID is a ... not a ...
 # ----------------------------------------
@@ -319,4 +326,11 @@ def syntax_error_already_declared(lineno: int, id_name: str, as_class: CLASS, at
     error(lineno, f"'{id_name}' already declared as {as_class} at {at_lineno}")
 
 
+# ----------------------------------------
+#  Can't declare a mandatory parameter after an optional one
+# ----------------------------------------
+def syntax_error_mandatory_param_after_optional(lineno: int, param1: str, param2: str):
+    error(lineno, f"Can't declare mandatory param '{param2}' after optional param '{param1}'")
+
+
 # endregion

src/api/symboltable.py

@@ -35,6 +35,7 @@
 from .errmsg import warning_not_used
 from .errmsg import syntax_error_func_type_mismatch
 from .errmsg import syntax_error_not_array_nor_func
+from .errmsg import syntax_error_cannot_define_default_array_argument
 
 from .constants import DEPRECATED_SUFFIXES
 from .constants import SUFFIX_TYPE
@@ -695,26 +696,33 @@ def declare_label(self, id_: str, lineno: int) -> Optional[SymbolLABEL]:
         entry.type_ = self.basic_types[global_.PTR_TYPE]
         return entry
 
-    def declare_param(self, id_: str, lineno: int, type_=None, is_array=False) -> Optional[SymbolVAR]:
+    def declare_param(
+        self, id_: str, lineno: int, type_=None, is_array=False, default_value: Optional[Symbol] = None
+    ) -> Optional[SymbolVAR]:
         """Declares a parameter
         Check if entry.declared is False. Otherwise raises an error.
         """
         if not self.check_is_undeclared(id_, lineno, classname="parameter", scope=self.current_scope, show_error=True):
             return None
 
         if is_array:
+            if default_value is not None:
+                syntax_error_cannot_define_default_array_argument(lineno)
+                return None
+
             entry = self.declare(id_, lineno, symbols.VARARRAY(id_, symbols.BOUNDLIST(), lineno, None, type_))
             entry.callable = True
             entry.scope = SCOPE.parameter
         else:
-            entry = self.declare(id_, lineno, symbols.PARAMDECL(id_, lineno, type_))
+            entry = self.declare(id_, lineno, symbols.PARAMDECL(id_, lineno, type_, default_value))
 
         if entry is None:
             return None
 
         entry.declared = True
         if entry.type_.implicit:
             warning_implicit_type(lineno, id_, type_)
+
         return entry
 
     def declare_array(self, id_: str, lineno: int, type_, bounds, default_value=None, addr=None):

src/arch/z80/translator.py

@@ -1447,7 +1447,7 @@ def visit_FUNCTION(self, node):
                 if local_var.default_value is not None:
                     r.extend(self.array_default_value(local_var.type_, local_var.default_value))
                 self.ic_larrd(local_var.offset, q, local_var.size, r, bound_ptrs)  # Initializes array bounds
-            elif local_var.class_ == CLASS.const:
+            elif local_var.class_ == CLASS.const or local_var.scope == SCOPE.parameter:
                 continue
             else:  # Local vars always defaults to 0, so if 0 we do nothing
                 if local_var.default_value is not None and local_var.default_value != 0:

src/parsetab/tabs.dbm.bak

@@ -1,4 +1,4 @@
 'zxbpp', (0, 76970)
 'asmparse', (77312, 268394)
 'zxnext_asmparse', (346112, 298411)
-'zxbparser', (644608, 703160)
+'zxbparser', (644608, 704752)

src/parsetab/tabs.dbm.dat

@@ -1,4 +1,4 @@
 'zxbpp', (0, 76970)
 'asmparse', (77312, 268394)
 'zxnext_asmparse', (346112, 298411)
-'zxbparser', (644608, 703160)
+'zxbparser', (644608, 704752)

src/parsetab/tabs.dbm.dir

@@ -8,23 +8,27 @@
 # This program is Free Software and is released under the terms of
 #                    the GNU General License
 # ----------------------------------------------------------------------
+from typing import Optional
+
+import src.api.global_ as gl
 
 from src.api.constants import CLASS
 from src.api.constants import SCOPE
 from src.api.config import OPTIONS
-import src.api.global_ as gl
-from .type_ import SymbolBASICTYPE as BasicType
-from .var import SymbolVAR
+from src.symbols.type_ import SymbolBASICTYPE as BasicType
+from src.symbols.var import SymbolVAR
+from src.symbols.symbol_ import Symbol
 
 
 class SymbolPARAMDECL(SymbolVAR):
     """Defines a parameter declaration"""
 
-    def __init__(self, varname, lineno, type_=None):
-        super(SymbolPARAMDECL, self).__init__(varname, lineno, type_=type_, class_=CLASS.var)
+    def __init__(self, varname: str, lineno: int, type_=None, default_value: Optional[Symbol] = None):
+        super().__init__(varname, lineno, type_=type_, class_=CLASS.var)
         self.byref = OPTIONS.default_byref  # By default all params By value (false)
         self.offset = None  # Set by PARAMLIST, contains positive offset from top of the stack
         self.scope = SCOPE.parameter
+        self.default_value = default_value
 
     @property
     def size(self):

src/symbols/paramdecl.py

@@ -411,9 +411,9 @@ def make_call(id_: str, lineno: int, args: symbols.ARGLIST):
     return make_func_call(id_, lineno, args)
 
 
-def make_param_decl(id_: str, lineno: int, typedef, is_array=False):
+def make_param_decl(id_: str, lineno: int, typedef, is_array: bool, default_value: Optional[symbols.SYMBOL] = None):
     """Wrapper that creates a param declaration"""
-    return SYMBOL_TABLE.declare_param(id_, lineno, typedef, is_array)
+    return SYMBOL_TABLE.declare_param(id_, lineno, typedef, is_array, default_value)
 
 
 def make_type(typename, lineno, implicit=False):
@@ -2931,6 +2931,10 @@ def p_param_decl_list(p):
 
 def p_param_decl_list2(p):
     """param_decl_list : param_decl_list COMMA param_definition"""
+    if p[1] is not None and p[3] is not None:  # No errors in parsing
+        if p[3].default_value is None and p[1][-1].default_value is not None:
+            src.api.errmsg.syntax_error_mandatory_param_after_optional(p[3].lineno, p[1][-1].name, p[3].name)
+
     p[0] = make_param_list(p[1], p[3])
 
 
@@ -2981,13 +2985,32 @@ def p_param_def_array(p):
 
 
 def p_param_def_type(p):
-    """param_def : singleid typedef"""
+    """param_def : singleid typedef default_arg_value"""
     id_: Id = p[1]
     typedef = p[2]
     if typedef is not None:
         src.api.check.check_type_is_explicit(id_.lineno, id_.name, typedef)
 
-    p[0] = make_param_decl(id_.name, id_.lineno, typedef)
+    default_value = make_typecast(typedef, p[3], id_.lineno)
+    p[0] = make_param_decl(
+        id_.name,
+        id_.lineno,
+        typedef,
+        is_array=False,
+        default_value=default_value,
+    )
+
+
+def p_param_def_default_arg_value(p):
+    """default_arg_value :
+    | EQ expr
+    """
+    if len(p) == 1:
+        p[0] = None
+        return
+
+    p[0] = p[2]
+    return
 
 
 def p_function_body(p):
@@ -3307,7 +3330,7 @@ def p_sgn(p):
 
 
 # ----------------------------------------
-# Trigonometrics and LN, EXP, SQR
+# Trigonometric and LN, EXP, SQR
 # ----------------------------------------
 def p_expr_trig(p):
     """bexpr : math_fn bexpr %prec UMINUS"""