0.0.4-rc: multi auto-imports; generate mode (#5)

Author: ebonnal

README.md

@@ -39,6 +39,20 @@ f00
 f00bar
 ```
 
+## generate
+If the `_` variable is not used in the expression, its value is outputed:
+```bash
+pythoned '"\n".join(map(str, range(5)))'
+```
+output:
+```
+0
+1
+2
+3
+4
+```
+
 ## modules
 
 Modules are auto-imported, example with `re`:

pythoned/__init__.py

@@ -1,34 +1,56 @@
+import ast
 import importlib
 import os
 import re
 from types import ModuleType
-from typing import Dict, Iterator
-
+from typing import Any, Dict, Iterator, Set
 
+LINE_IDENTIFIER = "_"
 _TYPE_ERROR_MSG = "The provided expression must be an str (editing) or a bool (filtering), but got {}."
 
 
+def iter_identifiers(expr: str) -> Iterator[str]:
+    for node in iter_asts(ast.parse(expr, mode="eval").body):
+        if isinstance(node, ast.Name):
+            yield node.id
+
+
+def iter_asts(node: ast.AST) -> Iterator[ast.AST]:
+    """
+    Depth-first traversal of nodes
+    """
+    yield node
+    yield from (
+        name for child in ast.iter_child_nodes(node) for name in iter_asts(child)
+    )
+
+
+def auto_import_eval(expression: str, globals: Dict[str, Any]) -> Any:
+    globals = globals.copy()
+    encountered_name_errors: Set[str] = set()
+    while True:
+        try:
+            return eval(expression, globals)
+        except NameError as name_error:
+            if str(name_error) in encountered_name_errors:
+                raise
+            encountered_name_errors.add(str(name_error))
+            match = re.match(r"name '([A-Za-z]+)'.*", str(name_error))
+            if match:
+                module = match.group(1)
+                globals[module] = importlib.import_module(module)
+                continue
+
+
 def edit(lines: Iterator[str], expression) -> Iterator[str]:
     modules: Dict[str, ModuleType] = {}
+
     for line in lines:
         linesep = ""
         if line.endswith(os.linesep):
             linesep, line = os.linesep, line[: -len(os.linesep)]
-        globals = {"_": line, **modules}
-        try:
-            value = eval(expression, globals)
-        except NameError as name_error:
-            match = re.match(r"name '([A-Za-z]+)'.*", str(name_error))
-            if match:
-                module = match.group(1)
-            else:
-                raise name_error
-            try:
-                modules[module] = importlib.import_module(module)
-                globals = {"_": line, **modules}
-            except:
-                raise name_error
-            value = eval(expression, globals)
+        globals = {LINE_IDENTIFIER: line, **modules}
+        value = auto_import_eval(expression, globals)
         if isinstance(value, str):
             yield value + linesep
         elif isinstance(value, bool):

pythoned/__main__.py

@@ -1,7 +1,7 @@
 import argparse
 import sys
 
-from pythoned import edit
+from pythoned import LINE_IDENTIFIER, auto_import_eval, edit, iter_identifiers
 
 
 def main() -> int:
@@ -10,8 +10,11 @@ def main() -> int:
 
     args = arg_parser.parse_args()
     expression: str = args.expression
-    for output_line in edit(sys.stdin, expression):
-        print(output_line, end="")
+    if not LINE_IDENTIFIER in iter_identifiers(expression):
+        print(auto_import_eval(expression, {}))
+    else:
+        for output_line in edit(sys.stdin, expression):
+            print(output_line, end="")
     return 0
 
 

tests/test.py

@@ -31,7 +31,7 @@ def test_edit(self) -> None:
             msg="_ must exclude linesep",
         )
         self.assertEqual(
-            list(edit(lines(), "str(int(math.pow(10, len(_))))")),
-            ["1000\n", "1000\n", "1000000"],
+            list(edit(lines(), "re.sub('[0]', 'O', str(int(math.pow(10, len(_)))))")),
+            ["1OOO\n", "1OOO\n", "1OOOOOO"],
             msg="modules should be auto-imported",
         )

version.py

@@ -1,2 +1,2 @@
 # to show the CHANGELOG: git log -- version.py
-__version__ = "0.0.3"
+__version__ = "0.0.4-rc"