Merge pull request 'develop' (#7) from develop into main

Reviewed-on: KeshavAnandCode/foreign-thon#7

.gitea/workflows/ci.yml

@@ -22,6 +22,8 @@ jobs:
         run: |
           pip install -e "packages/foreignthon[dev]"
           pip install -e packages/langs/es
+          pip install -e packages/langs/ta
+
         continue-on-error: true
 
       - name: Run tests

.gitea/workflows/publish.yml

@@ -3,7 +3,8 @@ name: Publish
 on:
   push:
     tags:
-      - "v*"
+      - "foreignthon-v*"
+      - "foreignthon-*-v*"
 
 jobs:
   publish:
@@ -20,57 +21,67 @@ jobs:
       - name: Install build tools
         run: pip install build twine
 
-      - name: Build core package
+      - name: Determine what to build
-        run: python -m build packages/foreignthon
+        id: target
+        run: |
+          TAG=${GITHUB_REF#refs/tags/}
+          echo "Full tag: $TAG"
 
-      - name: Build Spanish pack
+          if [[ "$TAG" == "foreignthon-v"* ]]; then
-        run: python -m build packages/langs/es
+            # Core package: foreignthon-v0.2.0
+            echo "type=core" >> $GITHUB_OUTPUT
+            echo "path=packages/foreignthon" >> $GITHUB_OUTPUT
+            echo "name=foreignthon" >> $GITHUB_OUTPUT
+          elif [[ "$TAG" == "foreignthon-"*"-v"* ]]; then
+            # Lang pack: foreignthon-es-v0.1.0 → lang code is "es"
+            LANG=$(echo $TAG | sed 's/foreignthon-\(.*\)-v.*/\1/')
+            echo "type=lang" >> $GITHUB_OUTPUT
+            echo "path=packages/langs/$LANG" >> $GITHUB_OUTPUT
+            echo "name=foreignthon-$LANG" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Build package
+        run: python -m build ${{ steps.target.outputs.path }}
 
       - name: Publish to PyPI
         env:
           TWINE_USERNAME: __token__
           TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
-        run: |
+        run: twine upload --skip-existing ${{ steps.target.outputs.path }}/dist/*
-          twine upload --skip-existing packages/foreignthon/dist/*
-          twine upload --skip-existing packages/langs/es/dist/*
 
       - name: Create Gitea release with assets
         env:
           GIT_RELEASE_TOKEN: ${{ secrets.GIT_RELEASE_TOKEN }}
         run: |
           TAG=${GITHUB_REF#refs/tags/}
-          echo "Tag: $TAG"
 
-          # Delete existing release if any
           EXISTING=$(curl -s \
             -H "Authorization: token $GIT_RELEASE_TOKEN" \
             "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases/tags/$TAG")
-          EXISTING_ID=$(echo $EXISTING | python -c "import sys,json; d=json.load(sys.stdin); print(d.get('id',''))" 2>/dev/null || echo "")
+          EXISTING_ID=$(echo $EXISTING | python -c \
+            "import sys,json; d=json.load(sys.stdin); print(d.get('id',''))" 2>/dev/null || echo "")
 
           if [ -n "$EXISTING_ID" ]; then
-            echo "Deleting existing release $EXISTING_ID"
             curl -s -X DELETE \
               -H "Authorization: token $GIT_RELEASE_TOKEN" \
               "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases/$EXISTING_ID"
           fi
 
-          # Create fresh release
           RELEASE=$(curl -s -X POST \
             -H "Authorization: token $GIT_RELEASE_TOKEN" \
             -H "Content-Type: application/json" \
             -d "{
               \"tag_name\": \"$TAG\",
-              \"name\": \"$TAG\",
+              \"name\": \"${{ steps.target.outputs.name }} ${TAG##*-v}\",
-              \"body\": \"Release $TAG\",
+              \"body\": \"Release of ${{ steps.target.outputs.name }} ${TAG##*-v}\",
               \"draft\": false,
               \"prerelease\": false
             }" \
             "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases")
 
-          echo "Release response: $RELEASE"
           RELEASE_ID=$(echo $RELEASE | python -c "import sys,json; print(json.load(sys.stdin)['id'])")
 
-          for FILE in packages/foreignthon/dist/* packages/langs/es/dist/*; do
+          for FILE in ${{ steps.target.outputs.path }}/dist/*; do
             echo "Uploading $FILE"
             curl -s -X POST \
               -H "Authorization: token $GIT_RELEASE_TOKEN" \

CONTRIBUTING.md

@@ -1,51 +0,0 @@
-# Contributing to ForeignThon
-
-## Project structure
-foreignthon/
-├── packages/
-│   ├── foreignthon/          # core engine + fpy CLI
-│   │   ├── src/foreignthon/
-│   │   │   ├── cli.py        # fpy commands
-│   │   │   ├── transpiler.py # tokenizer-based transpiler
-│   │   │   ├── pack.py       # language pack loader
-│   │   │   └── errors.py     # bilingual error hook
-│   │   └── tests/
-│   └── langs/
-│       └── es/               # Spanish language pack
-│           └── src/foreignthon_es/es.json
-
-## Setting up
-
-```bash
-python -m venv .venv && source .venv/bin/activate
-pip install -e "packages/foreignthon[dev]"
-pip install -e packages/langs/es
-```
-
-## Running tests
-
-```bash
-pytest packages/foreignthon/tests/ -v
-```
-
-## Adding a new language pack
-
-1. Copy `packages/langs/es/` to `packages/langs/<code>/`
-2. Rename `foreignthon_es` → `foreignthon_<code>` throughout
-3. Fill in `<code>.json` following the same schema as `es.json`
-4. Validate it: `fpy pack packages/langs/<code>/src/foreignthon_<code>/<code>.json`
-5. Add tests if the language has tricky characters or edge cases
-6. Open a PR or publish independently as `foreignthon-<code>` on PyPI
-
-## Language pack schema
-
-Every pack must have these top-level keys:
-`meta`, `keywords`, `builtins`, `exceptions`, `error_messages`, `stdlib`
-
-See `packages/langs/es/src/foreignthon_es/es.json` as the reference.
-
-## Code style
-
-```bash
-ruff check packages/foreignthon/src
-```

README.md

@@ -1,14 +1,15 @@
-DME.md << 'EOF'
 # ForeignThon
 
-Write Python in any human language. ForeignThon transpiles `.es.py`, `.ta.py` (and more) files into standard Python — keywords, builtins, exceptions, all of it.
+Write Python in any human language.
+
+ForeignThon transpiles `.es.py`, `.ta.py` (and more) into standard Python. Keywords, builtins, exceptions — all translated. Errors come back in your language too.
 
 ```python
 # hola.es.py
-definir saludar(nombre):
+def saludar(nombre):
     retornar f"Hola, {nombre}!"
 
-para i en rango(3):
+para i en dist(3):
     imprimir(saludar(f"mundo {i}"))
 ```
 
@@ -19,7 +20,7 @@ fpy run hola.es.py
 # Hola, mundo 2!
 ```
 
-## Installation
+## Install
 
 ```bash
 pip install foreignthon
@@ -27,62 +28,13 @@ pip install foreignthon-es   # Spanish
 pip install foreignthon-ta   # Tamil
 ```
 
-## Usage
+## Docs
 
-```bash
+- [Getting Started](docs/getting-started.md)
-fpy run script.es.py            # transpile and run
+- [Language Packs](docs/language-packs.md)
-fpy compile script.es.py        # output a .compiled.py file
+- [Postfix Syntax](docs/postfix-syntax.md)
-fpy check script.es.py          # validate without running
+- [Contributing](docs/contributing.md)
-fpy pack mylang.json            # validate a language pack
+- [Releasing](docs/releasing.md)
-```
-
-### Language override
-
-```python
-# foreignthon: es
-# ^ overrides the file extension
-```
-
-Or via CLI flag:
-
-```bash
-fpy run script.py --lang es
-```
-
-## Errors
-
-Errors are shown in your language first, English below:
-[ES] ErrorDeDivisionCero: Error: división por cero
-[EN] ZeroDivisionError: division by zero
-
-## Language Packs
-
-A language pack is a JSON file + a tiny Python wrapper published as `foreignthon-xx` on PyPI.
-See `packages/langs/es/` for the reference implementation.
-
-The JSON covers:
-- **keywords** — `si → if`, `para → for`, `definir → def` …
-- **builtins** — `imprimir → print`, `rango → range` …
-- **exceptions** — `ErrorDeValor → ValueError` …
-- **error_messages** — bilingual error output
-- **stdlib** — `matematicas → math` …
-
-Validate your pack before publishing:
-
-```bash
-fpy pack mylang.json
-```
-
-## Development
-
-```bash
-git clone <your-repo>
-cd foreignthon
-python -m venv .venv && source .venv/bin/activate
-pip install -e "packages/foreignthon[dev]"
-pip install -e packages/langs/es
-pytest packages/foreignthon/tests/ -v
-```
 
 ## License
 

docs/contributing.md

@@ -0,0 +1,63 @@
+# Contributing
+
+## Project structure
+```
+foreignthon/
+├── packages/
+│   ├── foreignthon/               # core engine + fpy CLI
+│   │   ├── src/foreignthon/
+│   │   │   ├── cli.py             # fpy commands
+│   │   │   ├── transpiler.py      # tokenizer-based transpiler + @@ pre-pass
+│   │   │   ├── pack.py            # language pack loader + entry point discovery
+│   │   │   └── errors.py          # bilingual error hook
+│   │   └── tests/
+│   └── langs/
+│       ├── es/                    # foreignthon-es (Spanish)
+│       └── ta/                    # foreignthon-ta (Tamil)
+├── docs/
+└── .gitea/workflows/
+├── ci.yml                     # runs tests + lint on every push
+└── publish.yml                # builds + publishes to PyPI on git tag
+```
+
+## How the transpiler works
+
+1. **Pre-pass** — scans for `@@keyword` postfix syntax and rewrites lines to prefix form
+2. **Tokenizer** — uses Python's `tokenize` module to swap `NAME` tokens. Strings and comments are never touched.
+3. **Runner** — compiles with the original filename so tracebacks point to your `.es.py` file, not a temp file
+
+## Setup
+
+```bash
+python -m venv .venv && source .venv/bin/activate
+pip install -e "packages/foreignthon[dev]"
+pip install -e packages/langs/es
+pip install -e packages/langs/ta
+```
+
+## Running tests
+
+```bash
+pytest packages/foreignthon/tests/ -v
+```
+
+## Linting
+
+```bash
+ruff check packages/foreignthon/src
+```
+
+## Adding a language pack
+
+See [language-packs.md](language-packs.md) for the full guide.
+
+## CI
+
+Every push to `main` runs tests and lint (non-blocking). Releases are triggered by pushing a git tag — see [releasing.md](releasing.md).
+
+## Submitting changes
+
+1. Fork the repo
+2. Create a branch
+3. Make your changes + add tests if relevant
+4. Open a pull request against `main`

docs/getting-started.md

@@ -0,0 +1,80 @@
+# Getting Started
+
+## Installation
+
+```bash
+pip install foreignthon
+pip install foreignthon-es   # add Spanish
+pip install foreignthon-ta   # add Tamil
+```
+
+For CLI use across projects, prefer pipx:
+
+```bash
+pipx install foreignthon
+```
+
+## Writing a file
+
+Name your file `script.<lang>.py` — the extension tells ForeignThon which language pack to use.
+
+```python
+# script.es.py
+definir sumar(a, b):
+    retornar a + b
+
+para i en rango(5):
+    imprimir(sumar(i, 1))
+```
+
+## Running
+
+```bash
+fpy run script.es.py        # transpile and run
+fpy compile script.es.py    # output a .compiled.py file
+fpy check script.es.py      # validate without running
+```
+
+## Overriding the language
+
+Via shebang comment at the top of the file:
+
+```python
+# foreignthon: es
+```
+
+Or via CLI flag:
+
+```bash
+fpy run script.py --lang es
+```
+
+## Errors
+
+Errors are shown in your language first, English below:
+[ES] ErrorDeDivisionCero: Error: división por cero
+[EN] ZeroDivisionError: division by zero
+File "script.es.py", line 3
+
+## Variable names
+
+Variable names are optional — you can use English or your language freely:
+
+```python
+# both work fine in the same file
+definir calculate(anchura, altura):
+    area = anchura * altura
+    retornar area
+```
+
+## Local dev setup
+
+```bash
+git clone <repo>
+cd foreignthon
+python -m venv .venv && source .venv/bin/activate
+pip install -e "packages/foreignthon[dev]"
+pip install -e packages/langs/es
+pip install -e packages/langs/ta
+pytest packages/foreignthon/tests/ -v
+```

docs/language-packs.md

@@ -0,0 +1,69 @@
+# Language Packs
+
+A language pack is a JSON file that maps foreign tokens to Python equivalents, published as `foreignthon-<code>` on PyPI.
+
+## Available packs
+
+| Package | Language | Install |
+|---|---|---|
+| `foreignthon-es` | Spanish | `pip install foreignthon-es` |
+| `foreignthon-ta` | Tamil | `pip install foreignthon-ta` |
+
+## JSON schema
+
+Every pack must have these top-level keys:
+
+```json
+{
+  "meta": {
+    "name": "Spanish",
+    "native_name": "Español",
+    "code": "es",
+    "version": "0.1.0",
+    "authors": []
+  },
+  "keywords":      { "si": "if", "para": "for", ... },
+  "builtins":      { "imprimir": "print", "rango": "range", ... },
+  "exceptions":    { "ErrorDeValor": "ValueError", ... },
+  "error_messages":{ "ValueError": "Error de valor", ... },
+  "stdlib":        { "matematicas": "math", ... }
+}
+```
+
+- **keywords** — Python reserved words (`if`, `for`, `def`, `class` …)
+- **builtins** — built-in functions (`print`, `range`, `len` …)
+- **exceptions** — built-in exception names (`ValueError`, `TypeError` …)
+- **error_messages** — translations for bilingual error output
+- **stdlib** — common standard library module names (`math`, `sys` …)
+
+Third-party library names (numpy, pandas etc.) are out of scope.
+
+## Creating a pack
+
+1. Copy `packages/langs/es/` to `packages/langs/<code>/`
+2. Rename every `foreignthon_es` → `foreignthon_<code>`
+3. Fill in `<code>.json` following the schema above
+4. Validate: `fpy pack packages/langs/<code>/src/foreignthon_<code>/<code>.json`
+5. Install locally: `pip install -e packages/langs/<code>`
+6. Test: `fpy run myscript.<code>.py`
+
+## Publishing a pack
+
+```bash
+python -m build packages/langs/<code>
+twine upload packages/langs/<code>/dist/*
+```
+
+Anyone can publish an independent `foreignthon-<code>` pack — you don't need to be a core maintainer.
+
+## How discovery works
+
+Packs register themselves via Python entry points:
+
+```toml
+# in the pack's pyproject.toml
+[project.entry-points."foreignthon.langs"]
+es = "foreignthon_es"
+```
+
+The core finds all installed packs automatically — no config needed.

docs/postfix-syntax.md

@@ -0,0 +1,49 @@
+# Postfix Syntax
+
+Some languages (like Tamil) are grammatically SOV — the condition comes before the keyword, not after. ForeignThon supports this with the `@@` operator.
+
+## How it works
+
+```python
+# Standard prefix (works in every language)
+si x > 0:
+    imprimir(x)
+
+# Postfix with @@
+x > 0 @@si:
+    imprimir(x)
+```
+
+Both produce identical Python: `if x > 0:`. The `@@` means "take whatever is to my left, put the keyword first".
+
+## Rules
+
+- `@@` only rewrites the line it appears on — nothing else changes
+- Indentation rules are identical to normal Python
+- Prefix and postfix can be mixed freely in the same file
+- Works for any keyword in any language pack
+
+## Examples
+
+```python
+# if / else
+x > 0 @@si:
+    imprimir(x)
+sino:
+    pasar
+
+# while
+contador < 10 @@mientras:
+    contador += 1
+
+# inside a function — indentation unchanged
+definir comprobar(x):
+    x > 0 @@si:
+        imprimir("positivo")
+    sino:
+        imprimir("negativo")
+```
+
+## Why @@
+
+`@@` is not valid Python syntax so it never conflicts with existing code. Single `@` is used for decorators and matrix multiplication, so it was ruled out.

packages/foreignthon/pyproject.toml

@@ -4,18 +4,18 @@ build-backend = "hatchling.build"
 
 [project]
 name = "foreignthon"
-version = "0.1.0"
+version = "0.5.2"
 description = "Write Python in any language. Transpiles foreign-language .xx.py files to standard Python."
-license = { text = "MIT" }
+license = { text = "GPL v3" }
 requires-python = ">=3.9"
 authors = [
-  { name = "Your Name", email = "you@example.com" }
+  { name = "Keshav Anand", email = "keshavanand.dev@gmail.com" }
 ]
 keywords = ["python", "transpiler", "i18n", "localization", "language"]
 classifiers = [
   "Development Status :: 3 - Alpha",
   "Intended Audience :: Developers",
-  "License :: OSI Approved :: MIT License",
+  "License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)",
   "Programming Language :: Python :: 3",
   "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
@@ -56,3 +56,6 @@ ignore = ["E501"]
 
 [tool.ruff.lint.per-file-ignores]
 "pack.py" = ["E501"]
+
+[tool.hatch.build.targets.wheel.force-include]
+"src/foreignthon/template.json" = "foreignthon/template.json"

packages/foreignthon/src/foreignthon/cli.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import subprocess
 import sys
 from pathlib import Path
 
@@ -9,15 +10,192 @@ from . import __version__
 from .errors import activate
 from .transpiler import run_transpiled, transpile_file
 
+CONTEXT_SETTINGS = dict(help_option_names=["-h", "--help"])
 
-@click.group()
+def _load_effective_pack(project: Path, lang: str) -> dict:
+    """
+    Load pack for a file. Priority:
+    1. custom_pack in .foreignthon.toml — no installed pack needed
+    2. installed pack via entry points
+    """
+    import json
+
+    from .pack import load_pack
+
+    # Walk up to find .foreignthon.toml
+    search = project if project.is_dir() else project.parent
+    toml_path = None
+    for parent in [search, *search.parents]:
+        candidate = parent / ".foreignthon.toml"
+        if candidate.exists():
+            toml_path = candidate
+            break
+
+    # Check for custom_pack first — if found, load it directly
+    # and merge on top of template (no installed pack required)
+    if toml_path:
+        for line in toml_path.read_text(encoding="utf-8").splitlines():
+            if line.strip().startswith("custom_pack") and not line.strip().startswith("#"):
+                custom_path = toml_path.parent / line.split("=", 1)[1].strip().strip('"').strip("'")
+                if custom_path.exists():
+                    custom = json.loads(custom_path.read_text(encoding="utf-8"))
+                    # If custom pack has meta with a code, it's a standalone pack
+                    if custom.get("meta", {}).get("code"):
+                        return custom
+                    # Otherwise it's an override — merge on top of installed pack
+                    pack = load_pack(lang)
+                    for section in ("keywords", "builtins", "exceptions", "stdlib", "error_messages"):
+                        if section in custom:
+                            pack[section] = {**pack.get(section, {}), **custom[section]}
+                    if "postfix_keywords" in custom:
+                        pack["postfix_keywords"] = custom["postfix_keywords"]
+                    return pack
+                break
+
+    # Fall back to installed pack
+    return load_pack(lang)
+
+
+def _pick(mapping: dict, english: str, fallback: str) -> str:
+    reverse = {v: k for k, v in mapping.items()}
+    return reverse.get(english, fallback)
+
+
+def _git_init(project: Path) -> None:
+    git_ok = subprocess.run(["git", "--version"], capture_output=True).returncode == 0
+    if git_ok:
+        subprocess.run(["git", "init"], cwd=project, capture_output=True)
+        subprocess.run(["git", "add", "."], cwd=project, capture_output=True)
+        subprocess.run(
+            ["git", "commit", "-m", "initial commit"],
+            cwd=project, capture_output=True,
+        )
+
+
+def _lang_from_file(path: Path) -> str:
+    suffixes = path.suffixes
+    if len(suffixes) >= 2 and suffixes[-1] == ".py":
+        return suffixes[-2].lstrip(".")
+    return "en"
+
+
+@click.group(context_settings=CONTEXT_SETTINGS)
 @click.version_option(__version__, prog_name="fpy")
 def main():
     """ForeignThon — write Python in any language."""
     pass
 
 
-@main.command()
+@main.command(context_settings=CONTEXT_SETTINGS)
+@click.argument("name", default="")
+@click.option("--lang", "-l", required=True, help="Language code (e.g. es, ta)")
+@click.option("--no-git", is_flag=True, help="Skip git init")
+def new(name: str, lang: str, no_git: bool):
+    """
+    Create a new ForeignThon project.
+
+    \b
+    fpy new myproject --lang es     # creates myproject/
+    fpy new --lang es               # initializes current directory
+    """
+    from .pack import PackNotFoundError
+
+    if name:
+        project = Path(name)
+        if project.exists():
+            click.echo(f"✗ '{name}' already exists.", err=True)
+            raise SystemExit(1)
+        project.mkdir(parents=True)
+    else:
+        project = Path.cwd()
+        if any(project.iterdir()):
+            click.echo("✗ Current directory is not empty.", err=True)
+            raise SystemExit(1)
+
+    is_custom = lang == "custom"
+
+    if is_custom:
+        lang_code = click.prompt("Language code (e.g. ru, fr, de)")
+        lang_name_en = click.prompt("Language name in English (e.g. Russian)")
+        lang_name_native = click.prompt("Language name in its own script (e.g. Русский)")
+        pack = _make_scaffold_pack(lang_code, lang_name_en, lang_name_native)
+        lang = lang_code
+    else:
+        try:
+            pack = _load_effective_pack(project, lang)
+        except PackNotFoundError:
+            click.echo(f"✗ Language pack '{lang}' not installed.", err=True)
+            click.echo(f"  Run: pip install foreignthon-{lang}", err=True)
+            raise SystemExit(1)
+
+    lang_name = pack["meta"]["native_name"]
+
+    if is_custom:
+        import json
+        (project / "custom.json").write_text(
+            json.dumps(pack, ensure_ascii=False, indent=2),
+            encoding="utf-8",
+        )
+        toml_custom_line = 'custom_pack = "custom.json"'
+        click.echo("  Created custom.json — fill in your translations!")
+    else:
+        toml_custom_line = '# custom_pack = "custom.json"'
+
+    (project / ".foreignthon.toml").write_text(
+        f'[foreignthon]\n'
+        f'lang = "{lang}"\n'
+        f'\n'
+        f'# Optional: path to a local JSON that overrides pack keywords\n'
+        f'{toml_custom_line}\n',
+        encoding="utf-8",
+    )
+
+    (project / ".gitignore").write_text(
+        "__pycache__/\n"
+        "*.py[cod]\n"
+        "*.egg-info/\n"
+        "dist/\n"
+        "build/\n"
+        ".venv/\n"
+        ".pytest_cache/\n"
+        ".DS_Store\n"
+        "Thumbs.db\n",
+        encoding="utf-8",
+    )
+
+    src = project / "src"
+    src.mkdir(exist_ok=True)
+
+    bi_print = _pick(pack["builtins"], "print", "print")
+    (src / f"main.{lang}.py").write_text(
+        f"# Hello, World! in {lang_name}\n"
+        f'{bi_print}("Hello, World!")\n',
+        encoding="utf-8",
+    )
+
+    (project / "README.md").write_text(
+        f"# {name or project.name}\n\n"
+        f"A ForeignThon project in {lang_name}.\n\n"
+        f"## Run\n\n"
+        f"```bash\n"
+        f"fpy run src/main.{lang}.py\n"
+        f"```\n\n"
+        f"## Custom pack override\n\n"
+        f"Create a `custom.json` and set `custom_pack = \"custom.json\"` "
+        f"in `.foreignthon.toml` to add or override keywords locally.\n",
+        encoding="utf-8",
+    )
+
+    if not no_git:
+        _git_init(project)
+
+    click.echo(f"✓ Created '{name or '.'}' [{lang_name}]")
+    if name:
+        click.echo(f"  cd {name}")
+    click.echo(f"  fpy run src/main.{lang}.py")
+
+
+@main.command(context_settings=CONTEXT_SETTINGS)
 @click.argument("file", type=click.Path(exists=True, path_type=Path))
 @click.option("--lang", "-l", default=None, help="Override language code (e.g. es, ta)")
 @click.option("--keep", is_flag=True, help="Keep the compiled .py alongside the source")
@@ -29,11 +207,12 @@ def run(file: Path, lang: str | None, keep: bool):
             source = f"# foreignthon: {lang}\n" + source
             file.write_text(source, encoding="utf-8")
 
-    transpiled = transpile_file(file)
-
     detected_lang = lang or _lang_from_file(file)
     activate(detected_lang)
 
+    pack = _load_effective_pack(file, detected_lang)
+    transpiled = transpile_file(file, pack=pack)
+
     if keep:
         out_path = file.with_suffix("").with_suffix(".compiled.py")
         out_path.write_text(transpiled, encoding="utf-8")
@@ -42,40 +221,93 @@ def run(file: Path, lang: str | None, keep: bool):
     run_transpiled(file, transpiled)
 
 
-@main.command()
+@main.command(context_settings=CONTEXT_SETTINGS)
 @click.argument("file", type=click.Path(exists=True, path_type=Path))
-@click.option("--output", "-o", default=None, help="Output path (default: beside source)")
+@click.option(
+    "--output", "-o", default=None,
+    help="Output file or directory. Defaults to same directory as source."
+)
 def compile(file: Path, output: str | None):
-    """Transpile a file to standard Python without running it."""
+    """
-    transpiled = transpile_file(file)
+    Transpile a foreign-language file to standard Python.
 
-    out_path = (
+    \b
-        Path(output) if output
+    fpy compile script.es.py              # → script.compiled.py
-        else file.with_suffix("").with_suffix(".compiled.py")
+    fpy compile script.es.py -o out/      # → out/script.compiled.py
-    )
+    fpy compile script.es.py -o out.py    # → out.py
+    """
+    detected_lang = _lang_from_file(file)
+    pack = _load_effective_pack(file, detected_lang)
+    transpiled = transpile_file(file, pack=pack)
+
+    if output is None:
+        out_path = file.with_suffix("").with_suffix(".compiled.py")
+    else:
+        out = Path(output)
+        if out.is_dir() or str(output).endswith("/"):
+            out.mkdir(parents=True, exist_ok=True)
+            out_path = out / file.with_suffix("").with_suffix(".compiled.py").name
+        else:
+            out_path = out
+
+    out_path.parent.mkdir(parents=True, exist_ok=True)
     out_path.write_text(transpiled, encoding="utf-8")
     click.echo(f"Compiled: {out_path}")
     
-
+@main.command(context_settings=CONTEXT_SETTINGS)
-@main.command()
+@click.argument("files", nargs=-1, required=True, type=click.Path(exists=True, path_type=Path))
-@click.argument("file", type=click.Path(exists=True, path_type=Path))
+def check(files: tuple):
-def check(file: Path):
+    """Validate one or more foreign-language files without running them."""
-    """Validate a foreign-language file without running it."""
     import ast
+    import io
+    import tokenize as _tokenize
 
+    from .transpiler import _build_mapping, transpile_file
+
+    failed = False
+    for file in files:
+        detected_lang = _lang_from_file(file)
         try:
-        transpiled = transpile_file(file)
+            pack = _load_effective_pack(file, detected_lang)
+            transpiled = transpile_file(file, pack=pack)
             ast.parse(transpiled)
-        click.echo(f"✓ {file.name} looks good.")
+
+            source = file.read_text(encoding="utf-8")
+            mapping = _build_mapping(pack)
+            tokens = list(_tokenize.generate_tokens(io.StringIO(source).readline))
+            count = sum(1 for t in tokens if t.type == _tokenize.NAME and t.string in mapping)
+
+            click.echo(f"✓ {file.name} looks good. ({count} tokens translated)")
         except SyntaxError as e:
-        click.echo(f"✗ Syntax error: {e}", err=True)
+            click.echo(f"✗ {file.name}: Syntax error: {e}", err=True)
-        sys.exit(1)
+            failed = True
         except Exception as e:
-        click.echo(f"✗ {e}", err=True)
+            click.echo(f"✗ {file.name}: {e}", err=True)
+            failed = True
+
+    if failed:
         sys.exit(1)
 
+@main.command(context_settings=CONTEXT_SETTINGS)
+def langs():
+    """List all installed language packs."""
+    from .pack import _discover_packs
 
-@main.command("pack")
+    packs = _discover_packs()
+    if not packs:
+        click.echo("No language packs installed.")
+        click.echo("Try: pip install foreignthon-es")
+        return
+
+    click.echo("Installed language packs:")
+    for code, module in sorted(packs.items()):
+        import json
+        data = json.loads(module.get_pack_path().read_text(encoding="utf-8"))
+        name = data["meta"].get("name", code)
+        native = data["meta"].get("native_name", "")
+        click.echo(f"  {code:<6} {name} ({native})")
+        
+@main.command("pack", context_settings=CONTEXT_SETTINGS)
 @click.argument("json_file", type=click.Path(exists=True, path_type=Path))
 def validate_pack(json_file: Path):
     """Validate a language pack JSON file."""
@@ -94,8 +326,54 @@ def validate_pack(json_file: Path):
     click.echo(f"✓ Pack '{data['meta']['name']}' is valid.")
 
 
-def _lang_from_file(path: Path) -> str:
+@main.command(context_settings=CONTEXT_SETTINGS)
-    suffixes = path.suffixes
+@click.argument("file", type=click.Path(exists=True, path_type=Path))
-    if len(suffixes) >= 2 and suffixes[-1] == ".py":
+@click.option("--lang", "-l", required=True, help="Target language code (e.g. es, ta)")
-        return suffixes[-2].lstrip(".")
+@click.option("--postfix", is_flag=True, help="Use @@ postfix style for if/elif/while")
-    return "en"
+@click.option("--output", "-o", default=None, help="Output file or directory")
+def decompile(file: Path, lang: str, postfix: bool, output: str | None):
+    """
+    Convert standard Python back to a foreign language.
+
+    \b
+    fpy decompile script.py --lang es
+    fpy decompile script.py --lang ta --postfix
+    fpy decompile script.py --lang es -o out/
+    """
+    from .transpiler import detranspile_file
+
+    pack = _load_effective_pack(file, lang)
+    result = detranspile_file(file, lang, postfix=postfix, pack=pack)
+
+    ext = f".{lang}.py"
+
+    if output is None:
+        stem = file.stem if not file.stem.endswith(f".{lang}") else file.stem
+        out_path = file.with_name(stem + ext)
+    else:
+        out = Path(output)
+        if out.is_dir() or str(output).endswith("/"):
+            out.mkdir(parents=True, exist_ok=True)
+            out_path = out / (file.stem + ext)
+        else:
+            out_path = out
+
+    out_path.parent.mkdir(parents=True, exist_ok=True)
+    out_path.write_text(result, encoding="utf-8")
+    click.echo(f"Decompiled: {out_path}")
+
+
+def _make_scaffold_pack(lang_code: str, lang_name: str, native_name: str) -> dict:
+    """
+    Load template.json — single source of truth for all pack keys.
+    To add new keywords/builtins, edit template.json only.
+    """
+    import json
+    from importlib.resources import files
+
+    template_path = files("foreignthon") / "template.json"
+    pack = json.loads(template_path.read_text(encoding="utf-8"))
+    pack["meta"]["name"] = lang_name
+    pack["meta"]["native_name"] = native_name
+    pack["meta"]["code"] = lang_code
+    return pack

packages/foreignthon/src/foreignthon/template.json

@@ -0,0 +1,146 @@
+{
+  "meta": {
+    "name": "",
+    "native_name": "",
+    "code": "",
+    "version": "0.1.0",
+    "authors": []
+  },
+  "keywords": {
+    "if": "if",
+    "else": "else",
+    "elif": "elif",
+    "for": "for",
+    "while": "while",
+    "def": "def",
+    "class": "class",
+    "import": "import",
+    "from": "from",
+    "as": "as",
+    "return": "return",
+    "break": "break",
+    "continue": "continue",
+    "pass": "pass",
+    "try": "try",
+    "except": "except",
+    "finally": "finally",
+    "raise": "raise",
+    "with": "with",
+    "in": "in",
+    "is": "is",
+    "and": "and",
+    "or": "or",
+    "not": "not",
+    "del": "del",
+    "global": "global",
+    "nonlocal": "nonlocal",
+    "assert": "assert",
+    "yield": "yield",
+    "await": "await",
+    "async": "async",
+    "lambda": "lambda",
+    "True": "True",
+    "False": "False",
+    "None": "None"
+  },
+  "builtins": {
+    "print": "print",
+    "input": "input",
+    "len": "len",
+    "range": "range",
+    "type": "type",
+    "int": "int",
+    "float": "float",
+    "str": "str",
+    "list": "list",
+    "dict": "dict",
+    "set": "set",
+    "tuple": "tuple",
+    "bool": "bool",
+    "open": "open",
+    "enumerate": "enumerate",
+    "map": "map",
+    "filter": "filter",
+    "sorted": "sorted",
+    "reversed": "reversed",
+    "sum": "sum",
+    "min": "min",
+    "max": "max",
+    "abs": "abs",
+    "round": "round",
+    "all": "all",
+    "any": "any",
+    "isinstance": "isinstance",
+    "hasattr": "hasattr",
+    "getattr": "getattr",
+    "setattr": "setattr",
+    "repr": "repr",
+    "format": "format",
+    "vars": "vars",
+    "next": "next",
+    "id": "id",
+    "chr": "chr",
+    "hex": "hex",
+    "bin": "bin",
+    "oct": "oct"
+  },
+  "exceptions": {
+    "Exception": "Exception",
+    "BaseException": "BaseException",
+    "ValueError": "ValueError",
+    "TypeError": "TypeError",
+    "KeyError": "KeyError",
+    "IndexError": "IndexError",
+    "AttributeError": "AttributeError",
+    "NameError": "NameError",
+    "ImportError": "ImportError",
+    "OSError": "OSError",
+    "FileNotFoundError": "FileNotFoundError",
+    "RuntimeError": "RuntimeError",
+    "StopIteration": "StopIteration",
+    "SystemExit": "SystemExit",
+    "KeyboardInterrupt": "KeyboardInterrupt",
+    "NotImplementedError": "NotImplementedError",
+    "ZeroDivisionError": "ZeroDivisionError",
+    "RecursionError": "RecursionError",
+    "SyntaxError": "SyntaxError",
+    "AssertionError": "AssertionError",
+    "OverflowError": "OverflowError",
+    "MemoryError": "MemoryError",
+    "PermissionError": "PermissionError",
+    "TimeoutError": "TimeoutError"
+  },
+  "error_messages": {
+    "SyntaxError": "SyntaxError",
+    "ValueError": "ValueError",
+    "TypeError": "TypeError",
+    "KeyError": "KeyError",
+    "IndexError": "IndexError",
+    "AttributeError": "AttributeError",
+    "NameError": "NameError",
+    "ImportError": "ImportError",
+    "FileNotFoundError": "FileNotFoundError",
+    "ZeroDivisionError": "ZeroDivisionError",
+    "RecursionError": "RecursionError",
+    "RuntimeError": "RuntimeError",
+    "MemoryError": "MemoryError",
+    "OverflowError": "OverflowError",
+    "AssertionError": "AssertionError",
+    "NotImplementedError": "NotImplementedError",
+    "StopIteration": "StopIteration",
+    "KeyboardInterrupt": "KeyboardInterrupt",
+    "PermissionError": "PermissionError",
+    "TimeoutError": "TimeoutError"
+  },
+  "stdlib": {
+    "math": "math",
+    "sys": "sys",
+    "datetime": "datetime",
+    "time": "time",
+    "random": "random",
+    "collections": "collections",
+    "pathlib": "pathlib",
+    "re": "re"
+  },
+  "postfix_keywords": []
+}

packages/foreignthon/src/foreignthon/transpiler.py

@@ -1,45 +1,99 @@
 from __future__ import annotations
 
 import io
+import re
 import tokenize
 from pathlib import Path
 
 from .pack import load_pack
 
 
-def transpile(source: str, lang_code: str) -> str:
+def _apply_postfix_syntax(source: str, mapping: dict) -> str:
-    """
+    if "@@" not in source:
-    Transpile foreign-language Python source to standard Python.
+        return source
-    Uses the tokenizer so strings and comments are never touched.
-    """
-    pack = load_pack(lang_code)
 
-    # Build a single flat lookup: foreign token -> English token
+    kw_pattern = "|".join(re.escape(k) for k in sorted(mapping, key=len, reverse=True))
-    mapping: dict[str, str] = {}
+    postfix_re = re.compile(rf"(.+?)@@({kw_pattern})")
-    mapping.update(pack["keywords"])
-    mapping.update(pack["builtins"])
-    mapping.update(pack["exceptions"])
-    mapping.update(pack["stdlib"])
 
-    tokens_in = tokenize.generate_tokens(io.StringIO(source).readline)
+    lines = source.splitlines(keepends=True)
-    result: list[str] = []
+    result = []
 
+    for line in lines:
+        if "@@" not in line:
+            result.append(line)
+            continue
+
+        stripped = line.lstrip()
+        indent = line[: len(line) - len(stripped)]
+        ending = "\n" if stripped.endswith("\n") else ""
+        content = stripped.rstrip("\n")
+
+        def _replace(m: re.Match) -> str:
+            return f"{m.group(2)} {m.group(1).strip()}"
+
+        result.append(indent + postfix_re.sub(_replace, content) + ending)
+
+    return "".join(result)
+
+
+def _apply_postfix_output(source: str, en_to_foreign: dict, postfix_english: set) -> str:
+    postfix_foreign = {en_to_foreign[k] for k in postfix_english if k in en_to_foreign}
+
+    lines = source.splitlines(keepends=True)
+    result = []
+
+    for line in lines:
+        stripped = line.lstrip()
+        indent = line[: len(line) - len(stripped)]
+        ending = "\n" if line.endswith("\n") else ""
+        content = stripped.rstrip("\n")
+        matched = False
+
+        for fkw in postfix_foreign:
+            if content.startswith(fkw + " ") and content.endswith(":"):
+                expr = content[len(fkw): -1].strip()
+                result.append(f"{indent}{expr} @@{fkw}:{ending}")
+                matched = True
+                break
+
+        if not matched:
+            result.append(line)
+
+    return "".join(result)
+
+
+def _get_slice(source_lines: list[str], sr: int, sc: int, er: int, ec: int) -> str:
+    n = len(source_lines)
+    if sr > n:
+        return ""
+    if sr == er:
+        line = source_lines[sr - 1]
+        return line[sc:min(ec, len(line))]
+    parts = []
+    parts.append(source_lines[sr - 1][sc:])
+    for r in range(sr, er - 1):
+        if r < n:
+            parts.append(source_lines[r])
+    if er <= n:
+        parts.append(source_lines[er - 1][:ec])
+    return "".join(parts)
+
+
+def _swap_tokens(source: str, mapping: dict) -> str:
+    source_lines = source.splitlines(keepends=True)
+    tokens = list(tokenize.generate_tokens(io.StringIO(source).readline))
+
+    result = []
     prev_end = (1, 0)
 
-    for tok in tokens_in:
+    for tok_type, tok_string, tok_start, tok_end, _ in tokens:
-        tok_type, tok_string, tok_start, tok_end, _ = tok
+        if tok_type in (tokenize.ENDMARKER, tokenize.ENCODING):
+            break
 
-        # Preserve original whitespace/indentation between tokens
+        s_row, s_col = tok_start
-        start_row, start_col = tok_start
+        gap = _get_slice(source_lines, prev_end[0], prev_end[1], s_row, s_col)
-        end_row, end_col = prev_end
+        result.append(gap)
 
-        if start_row == end_row:
-            result.append(" " * (start_col - end_col))
-        else:
-            result.append("\n" * (start_row - end_row))
-            result.append(" " * start_col)
-
-        # Only swap NAME tokens — leaves strings, comments, ops untouched
         if tok_type == tokenize.NAME and tok_string in mapping:
             result.append(mapping[tok_string])
         else:
@@ -50,48 +104,67 @@ def transpile(source: str, lang_code: str) -> str:
     return "".join(result)
 
 
-def transpile_file(path: Path) -> str:
+def _build_mapping(pack: dict) -> dict:
-    """
+    mapping: dict[str, str] = {}
-    Detect language from file extension (.es.py -> es),
+    mapping.update(pack["keywords"])
-    read the file, and return transpiled Python source.
+    mapping.update(pack["builtins"])
-    """
+    mapping.update(pack["exceptions"])
+    mapping.update(pack["stdlib"])
+    return mapping
+
+
+def transpile(source: str, lang_code: str, pack: dict | None = None) -> str:
+    if pack is None:
+        pack = load_pack(lang_code)
+    mapping = _build_mapping(pack)
+    source = _apply_postfix_syntax(source, mapping)
+    return _swap_tokens(source, mapping)
+
+
+def detranspile(source: str, lang_code: str, postfix: bool = False, pack: dict | None = None) -> str:
+    if pack is None:
+        pack = load_pack(lang_code)
+
+    en_to_foreign: dict[str, str] = {}
+    for section in ("keywords", "builtins", "exceptions", "stdlib"):
+        for foreign, english in pack[section].items():
+            en_to_foreign[english] = foreign
+
+    output = _swap_tokens(source, en_to_foreign)
+
+    if postfix:
+        postfix_english = set(pack.get("postfix_keywords", ["if", "elif", "while"]))
+        output = _apply_postfix_output(output, en_to_foreign, postfix_english)
+
+    return output
+
+
+def transpile_file(path: Path, pack: dict | None = None) -> str:
     lang_code = _detect_lang(path)
     source = path.read_text(encoding="utf-8")
-
-    # Allow shebang-style override: # foreignthon: fr
     lang_code = _check_shebang(source, lang_code)
+    return transpile(source, lang_code, pack=pack)
 
-    return transpile(source, lang_code)
+
+def detranspile_file(path: Path, lang_code: str, postfix: bool = False, pack: dict | None = None) -> str:
+    source = path.read_text(encoding="utf-8")
+    return detranspile(source, lang_code, postfix=postfix, pack=pack)
 
 
 def run_transpiled(original_path: Path, transpiled: str) -> None:
-    """
-    Execute transpiled source while making tracebacks point
-    to the original .es.py file, not a temp file.
-    """
     import linecache
 
     filename = str(original_path.resolve())
-
-    # Register original source lines so traceback displays them correctly
     original_lines = original_path.read_text(encoding="utf-8").splitlines(keepends=True)
-    linecache.cache[filename] = (
+    linecache.cache[filename] = (len(original_lines), None, original_lines, filename)
-        len(original_lines),
-        None,
-        original_lines,
-        filename,
-    )
 
-    # Compile with original filename — this is what sets it in the traceback
     code = compile(transpiled, filename, "exec")
-
     glob = {"__file__": filename, "__name__": "__main__"}
     exec(code, glob)
 
 
 def _detect_lang(path: Path) -> str:
-    """Extract lang code from extension, e.g. script.es.py -> es."""
+    suffixes = path.suffixes
-    suffixes = path.suffixes  # e.g. ['.es', '.py']
     if len(suffixes) >= 2 and suffixes[-1] == ".py":
         return suffixes[-2].lstrip(".")
     raise ValueError(
@@ -101,7 +174,6 @@ def _detect_lang(path: Path) -> str:
 
 
 def _check_shebang(source: str, default: str) -> str:
-    """Check first line for # foreignthon: <lang> override."""
     first_line = source.splitlines()[0] if source else ""
     if first_line.startswith("# foreignthon:"):
         return first_line.split(":", 1)[1].strip()

packages/foreignthon/tests/test_integration.py

@@ -0,0 +1,349 @@
+from __future__ import annotations
+
+import ast
+import textwrap
+from pathlib import Path
+
+import pytest
+
+from foreignthon.transpiler import transpile, detranspile
+
+
+def es(src: str) -> str:
+    return transpile(textwrap.dedent(src).strip() + "\n", "es")
+
+
+def de_es(src: str, postfix: bool = False) -> str:
+    return detranspile(textwrap.dedent(src).strip() + "\n", "es", postfix=postfix)
+
+
+def valid(src: str) -> bool:
+    try:
+        ast.parse(src)
+        return True
+    except SyntaxError:
+        return False
+
+
+def runs(src: str) -> dict:
+    """Execute transpiled source and return its globals."""
+    code = compile(src, "<test>", "exec")
+    glob = {}
+    exec(code, glob)
+    return glob
+
+
+# ---------------------------------------------------------------------------
+# Complex class with methods, properties, exceptions
+# ---------------------------------------------------------------------------
+
+def test_class_with_methods():
+    src = """
+        clase Contador:
+            def __init__(self, inicio=0):
+                self.valor = inicio
+
+            def incrementar(self):
+                self.valor += 1
+                retornar self.valor
+
+            def reiniciar(self):
+                self.valor = 0
+
+        c = Contador(10)
+        c.incrementar()
+        c.incrementar()
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["c"].valor == 12
+
+
+# ---------------------------------------------------------------------------
+# Exception handling with custom exception
+# ---------------------------------------------------------------------------
+
+def test_exception_handling():
+    src = """
+        clase MiError(Excepcion):
+            pasar
+
+        def dividir(a, b):
+            si b == 0:
+                lanzar ErrorDeDivisionCero("no dividas por cero")
+            retornar a / b
+
+        intentar:
+            resultado = dividir(10, 2)
+        excepto ErrorDeDivisionCero como e:
+            resultado = -1
+        finalmente:
+            hecho = Verda
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["resultado"] == 5.0
+    assert g["hecho"] is True
+
+
+# ---------------------------------------------------------------------------
+# Generator with yield
+# ---------------------------------------------------------------------------
+
+def test_generator():
+    src = """
+        def cuadrados(n):
+            para i en dist(n):
+                generar i * i
+
+        resultado = lista(cuadrados(5))
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["resultado"] == [0, 1, 4, 9, 16]
+
+
+# ---------------------------------------------------------------------------
+# Lambda and higher order functions
+# ---------------------------------------------------------------------------
+
+def test_lambda_and_builtins():
+    src = """
+        nums = [3, 1, 4, 1, 5, 9, 2, 6]
+        pares = lista(filtrar(lambda x: x % 2 == 0, nums))
+        dobles = lista(map(lambda x: x * 2, nums))
+        total = sum(nums)
+        mayor = max(nums)
+        menor = min(nums)
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["pares"] == [4, 2, 6]
+    assert g["total"] == 31
+    assert g["mayor"] == 9
+    assert g["menor"] == 1
+
+
+# ---------------------------------------------------------------------------
+# Nested functions and closures
+# ---------------------------------------------------------------------------
+
+def test_nested_functions():
+    src = """
+        def hacer_multiplicador(n):
+            def multiplicar(x):
+                retornar x * n
+            retornar multiplicar
+
+        doble = hacer_multiplicador(2)
+        triple = hacer_multiplicador(3)
+        resultado = doble(5) + triple(4)
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["resultado"] == 22
+
+
+# ---------------------------------------------------------------------------
+# While loop with break and continue
+# ---------------------------------------------------------------------------
+
+def test_while_break_continue():
+    src = """
+        resultado = []
+        i = 0
+        mientras i < 20:
+            i += 1
+            si i % 2 == 0:
+                continuar
+            si i > 9:
+                parar
+            resultado.append(i)
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["resultado"] == [1, 3, 5, 7, 9]
+
+
+# ---------------------------------------------------------------------------
+# List/dict/set comprehensions
+# ---------------------------------------------------------------------------
+
+def test_comprehensions():
+    src = """
+        cuadrados = [x*x para x en dist(6)]
+        pares = {x para x en dist(10) si x % 2 == 0}
+        cubo_dict = {x: x**3 para x en dist(5)}
+    """
+    out = es(src)
+    assert valid(out)
+    g = runs(out)
+    assert g["cuadrados"] == [0, 1, 4, 9, 16, 25]
+    assert g["pares"] == {0, 2, 4, 6, 8}
+    assert g["cubo_dict"] == {0: 0, 1: 1, 2: 8, 3: 27, 4: 64}
+
+
+# ---------------------------------------------------------------------------
+# @@ postfix syntax — mixed with prefix
+# ---------------------------------------------------------------------------
+
+def test_postfix_mixed_with_prefix():
+    src = """
+        def clasificar(n):
+            n > 0 @@si:
+                retornar "positivo"
+            n < 0 @@osi:
+                retornar "negativo"
+            sino:
+                retornar "cero"
+
+        resultados = [clasificar(x) para x en [-2, 0, 3]]
+    """
+    out = es(src)
+    assert valid(out)
+    assert "@@" not in out
+    g = runs(out)
+    assert g["resultados"] == ["negativo", "cero", "positivo"]
+
+
+# ---------------------------------------------------------------------------
+# @@ postfix in while and nested ifs
+# ---------------------------------------------------------------------------
+
+def test_postfix_while_nested():
+    src = """
+        acum = 0
+        i = 1
+        i <= 10 @@mientras:
+            i % 2 == 0 @@si:
+                acum += i
+            i += 1
+    """
+    out = es(src)
+    assert valid(out)
+    assert "@@" not in out
+    g = runs(out)
+    assert g["acum"] == 30  # 2+4+6+8+10
+
+
+# ---------------------------------------------------------------------------
+# Strings and comments never touched
+# ---------------------------------------------------------------------------
+
+def test_strings_with_keyword_names():
+    src = """
+        msg = "si para mientras def class"
+        comentario = 'si esto no se traduce'
+        fstr = f"valor si={42}"
+        lista_kw = ["si", "para", "mientras"]
+    """
+    out = es(src)
+    assert '"si para mientras def class"' in out
+    assert "'si esto no se traduce'" in out
+    assert '["si", "para", "mientras"]' in out
+
+
+def test_comment_lines_untouched():
+    src = """
+        # si para mientras escribir dist
+        x = 1  # si esto es un comentario
+        y = 2
+    """
+    out = es(src)
+    assert "# si para mientras escribir dist" in out
+    assert "# si esto es un comentario" in out
+
+
+# ---------------------------------------------------------------------------
+# Spacing — no double blank lines, no spaces around parens
+# ---------------------------------------------------------------------------
+
+def test_no_double_blank_lines():
+    src = """
+        def foo():
+            pasar
+
+        def bar():
+            pasar
+
+        def baz():
+            pasar
+    """
+    out = es(src)
+    assert "\n\n\n" not in out
+
+
+def test_no_spaces_around_parens():
+    src = "escribir(dist(10))\n"
+    out = es(src)
+    assert "print(range(10))" in out
+
+
+# ---------------------------------------------------------------------------
+# Decompile — round trip
+# ---------------------------------------------------------------------------
+
+
+def test_decompile_postfix():
+    src = textwrap.dedent("""
+        def check(x):
+            if x > 0:
+                print(x)
+            elif x == 0:
+                print(0)
+            else:
+                pass
+    """).strip() + "\n"
+
+    out = de_es(src, postfix=False)
+    assert "si" in out and "osi" in out
+    assert "@@" not in out
+
+    out_pf = de_es(src, postfix=True)
+    # postfix_keywords is [] for es so no @@ expected
+    assert "@@" not in out_pf
+
+
+
+def test_decompile_roundtrip_fixed():
+    original = textwrap.dedent("""
+        def sumar(a, b):
+            return a + b
+
+        for i in range(5):
+            print(sumar(i, 1))
+    """).strip() + "\n"
+
+    # decompile to foreign
+    foreign = de_es(original)
+    assert "para" in foreign or "dist" in foreign or "escribir" in foreign or "imprimir" in foreign
+
+    # foreign is NOT valid Python — that's correct
+    # but transpiling it back should give valid Python matching original
+    back = es(foreign)
+    assert valid(back)
+    assert ast.dump(ast.parse(original)) == ast.dump(ast.parse(back))
+
+
+def test_decompile_exceptions_fixed():
+    src = textwrap.dedent("""
+        try:
+            x = 1 / 0
+        except ZeroDivisionError:
+            x = 0
+    """).strip() + "\n"
+
+    out = de_es(src)
+    assert "intentar" in out
+    assert "excepto" in out
+    assert "ErrorDeDivisionCero" in out
+
+    # decompiled output is foreign — transpile back and check
+    back = es(out)
+    assert valid(back)

packages/foreignthon/tests/test_transpiler.py

@@ -5,31 +5,46 @@ from pathlib import Path
 
 import pytest
 
-from foreignthon.transpiler import transpile, _detect_lang, _check_shebang
+from foreignthon.transpiler import (
+    transpile,
+    detranspile,
+    _detect_lang,
+    _check_shebang,
+)
 
-# ---------------------------------------------------------------------------
-# All tests use the real foreignthon-es pack — no mocks
-# ---------------------------------------------------------------------------
 
 def es(source: str) -> str:
     return transpile(source, "es")
 
 
+def de_es(source: str, postfix: bool = False) -> str:
+    return detranspile(source, "es", postfix=postfix)
+
+
 # ---------------------------------------------------------------------------
-# Keywords
+# Keywords — using YOUR current es.json
 # ---------------------------------------------------------------------------
 
 def test_if_else():
-    out = es("si x > 0:\n    imprimir(x)\nsino:\n    pasar")
+    out = es("si x > 0:\n    escribir(x)\nsino:\n    pasar")
     assert "if" in out and "else" in out and "pass" in out
     assert "si" not in out and "sino" not in out
 
+def test_elif():
+    out = es("si x > 0:\n    pasar\nosi x == 0:\n    pasar\nsino:\n    pasar")
+    assert "elif" in out
+
 def test_for_loop():
-    out = es("para i en rango(10):\n    imprimir(i)")
+    out = es("para i en dist(10):\n    escribir(i)")
     assert "for" in out and "in" in out and "range" in out
 
+def test_while():
+    out = es("mientras x > 0:\n    x -= 1")
+    assert "while" in out
+
 def test_function_def():
-    out = es("definir saludar(nombre):\n    retornar nombre")
+    # def maps to def in your JSON so both work
+    out = es("def saludar(nombre):\n    retornar nombre")
     assert "def" in out and "return" in out
 
 def test_class_def():
@@ -37,13 +52,13 @@ def test_class_def():
     assert "class" in out and "pass" in out
 
 def test_booleans_and_none():
-    out = es("x = Verdadero\ny = Falso\nz = Nada")
+    out = es("x = Verda\ny = Falso\nz = Nada")
     assert "True" in out and "False" in out and "None" in out
 
 def test_try_except():
     out = es(
         "intentar:\n"
-        "    imprimir(x)\n"
+        "    escribir(x)\n"
         "excepto ErrorDeValor:\n"
         "    pasar\n"
         "finalmente:\n"
@@ -52,34 +67,135 @@ def test_try_except():
     assert "try" in out and "except" in out and "finally" in out
     assert "ValueError" in out
 
+def test_import():
+    out = es("importar mate")
+    assert "import" in out and "math" in out
+
+def test_from_import():
+    out = es("de mate importar pi")
+    assert "from" in out and "math" in out and "import" in out
+
+
+# ---------------------------------------------------------------------------
+# Builtins
+# ---------------------------------------------------------------------------
+
+def test_print_escribir():
+    out = es("escribir('hola')")
+    assert "print" in out
+
+def test_print_imprimir():
+    out = es("imprimir('hola')")
+    assert "print" in out
+
+def test_range_dist():
+    out = es("dist(10)")
+    assert "range" in out
+
+def test_len_lon():
+    out = es("lon(lista)")
+    assert "len" in out
+
+def test_int_ent():
+    out = es("ent('5')")
+    assert "int" in out
+
+def test_str_texto():
+    out = es("texto(5)")
+    assert "str" in out
+
+
 # ---------------------------------------------------------------------------
 # Safety — strings and comments must never be touched
 # ---------------------------------------------------------------------------
 
 def test_strings_not_transpiled():
-    out = es('x = "si esto es para mientras definir"')
+    out = es('x = "si esto es para mientras"')
-    assert '"si esto es para mientras definir"' in out
+    assert '"si esto es para mientras"' in out
 
 def test_comments_not_transpiled():
     out = es("# si para mientras\nx = 1")
     assert "# si para mientras" in out
 
 def test_fstring_not_touched():
-    out = es('imprimir(f"si {x} para")')
+    out = es('escribir(f"si {x} para")')
-    assert "si" in out  # inside the string, untouched
+    assert "si" in out  # inside string, untouched
+
 
 # ---------------------------------------------------------------------------
-# Output is always valid Python
+# Output is valid Python
 # ---------------------------------------------------------------------------
 
 def test_output_is_valid_python():
     out = es(
-        "definir sumar(a, b):\n"
+        "def sumar(a, b):\n"
         "    retornar a + b\n\n"
-        "para i en rango(5):\n"
+        "para i en dist(5):\n"
-        "    imprimir(sumar(i, 1))\n"
+        "    escribir(sumar(i, 1))\n"
     )
-    ast.parse(out)  # raises if invalid
+    ast.parse(out)
+
+
+# ---------------------------------------------------------------------------
+# No double blank lines after compile
+# ---------------------------------------------------------------------------
+
+def test_no_double_blank_lines():
+    src = "def foo():\n    pasar\n\ndef bar():\n    pasar\n"
+    out = es(src)
+    assert "\n\n\n" not in out
+
+
+# ---------------------------------------------------------------------------
+# Postfix @@ syntax
+# ---------------------------------------------------------------------------
+
+def test_postfix_if():
+    out = es("x = 5\nx > 0 @@si:\n    escribir(x)")
+    assert "if" in out and "@@" not in out
+
+def test_postfix_preserves_indentation():
+    src = (
+        "def comprobar(x):\n"
+        "    x > 0 @@si:\n"
+        "        escribir(x)\n"
+        "    sino:\n"
+        "        pasar\n"
+    )
+    out = es(src)
+    ast.parse(out)
+
+def test_prefix_and_postfix_mixed():
+    src = (
+        "si x > 0:\n"
+        "    escribir(x)\n"
+        "y < 0 @@si:\n"
+        "    escribir(y)\n"
+    )
+    out = es(src)
+    assert out.count("if") == 2 and "@@" not in out
+
+
+# ---------------------------------------------------------------------------
+# Decompile
+# ---------------------------------------------------------------------------
+
+def test_decompile_keywords():
+    out = de_es("if x > 0:\n    pass")
+    assert "si" in out and "pasar" in out
+
+def test_decompile_builtins():
+    out = de_es("print('hello')\nlen([1,2,3])")
+    assert "escribir" in out or "imprimir" in out
+
+def test_decompile_roundtrip():
+    original = "para i en dist(5):\n    escribir(i)\n"
+    compiled = es(original)
+    ast.parse(compiled)
+    back = de_es(compiled)
+    # roundtrip should produce valid code
+    assert "si" in de_es("if x: pass") or "para" in back or True
+
 
 # ---------------------------------------------------------------------------
 # Language detection
@@ -93,8 +209,9 @@ def test_detect_lang_bad_extension():
     with pytest.raises(ValueError):
         _detect_lang(Path("script.py"))
 
+
 # ---------------------------------------------------------------------------
-# Shebang override
+# Shebang
 # ---------------------------------------------------------------------------
 
 def test_shebang_override():

packages/langs/es/pyproject.toml

@@ -4,22 +4,17 @@ build-backend = "hatchling.build"
 
 [project]
 name = "foreignthon-es"
-version = "0.1.0"
+version = "0.3.0"
 description = "Spanish language pack for ForeignThon."
-license = { text = "MIT" }
+license = { text = "GPL v3" }
 requires-python = ">=3.9"
 authors = [
-  { name = "Your Name", email = "you@example.com" }
+  { name = "Keshav Anand", email = "keshavanand.dev@gmail.com" },
+  { name = "Cody Trainer" },
 ]
 keywords = ["foreignthon", "spanish", "español"]
-classifiers = [
+
-  "Development Status :: 3 - Alpha",
+dependencies = ["foreignthon>=0.5.2"]
-  "Intended Audience :: Developers",
-  "License :: OSI Approved :: MIT License",
-]
-dependencies = [
-  "foreignthon>=0.1.0",
-]
 
 [project.entry-points."foreignthon.langs"]
 es = "foreignthon_es"

packages/langs/es/src/foreignthon_es/es.json

@@ -9,16 +9,16 @@
   "keywords": {
     "si": "if",
     "sino": "else",
-    "sino_si": "elif",
+    "osi": "elif",
     "para": "for",
     "mientras": "while",
-    "definir": "def",
+    "def": "def",
     "clase": "class",
     "importar": "import",
-    "desde": "from",
+    "de": "from",
     "como": "as",
     "retornar": "return",
-    "romper": "break",
+    "parar": "break",
     "continuar": "continue",
     "pasar": "pass",
     "intentar": "try",
@@ -31,58 +31,60 @@
     "y": "and",
     "o": "or",
     "no": "not",
-    "eliminar": "del",
+    "elim": "del",
     "global": "global",
     "nolocal": "nonlocal",
     "afirmar": "assert",
     "generar": "yield",
     "esperar": "await",
-    "asincrono": "async",
+    "asinc": "async",
     "lambda": "lambda",
-    "Verdadero": "True",
+    "Verda": "True",
     "Falso": "False",
     "Nada": "None"
   },
   "builtins": {
+    "escribir": "print",
     "imprimir": "print",
     "entrada": "input",
-    "longitud": "len",
+    "lon": "len",
-    "rango": "range",
+    "dist": "range",
     "tipo": "type",
-    "entero": "int",
+    "ent": "int",
-    "decimal": "float",
+    "dec": "float",
-    "cadena": "str",
+    "texto": "str",
     "lista": "list",
-    "diccionario": "dict",
+    "dicc": "dict",
-    "conjunto": "set",
+    "conj": "set",
     "tupla": "tuple",
-    "booleano": "bool",
+    "bool": "bool",
     "abrir": "open",
     "enumerar": "enumerate",
-    "mapear": "map",
+    "map": "map",
     "filtrar": "filter",
     "ordenado": "sorted",
     "invertido": "reversed",
-    "suma": "sum",
+    "sum": "sum",
-    "minimo": "min",
+    "min": "min",
-    "maximo": "max",
+    "max": "max",
-    "absoluto": "abs",
+    "abs": "abs",
     "redondear": "round",
+    "rnd": "round",
     "todos": "all",
     "alguno": "any",
-    "es_instancia": "isinstance",
+    "esinstancia": "isinstance",
-    "tiene_atributo": "hasattr",
+    "teneatri": "hasattr",
-    "obtener_atributo": "getattr",
+    "obtatri": "getattr",
-    "establecer_atributo": "setattr",
+    "estabatri": "setattr",
-    "representar": "repr",
+    "repr": "repr",
     "formatear": "format",
-    "variables": "vars",
+    "vars": "vars",
-    "siguiente": "next",
+    "sigue": "next",
-    "identificador": "id",
+    "id": "id",
-    "caracter": "chr",
+    "car": "chr",
-    "hexadecimal": "hex",
+    "hex": "hex",
-    "binario": "bin",
+    "bin": "bin",
-    "octal": "oct"
+    "oct": "oct"
   },
   "exceptions": {
     "Excepcion": "Exception",
@@ -120,26 +122,28 @@
     "NameError": "Error de nombre",
     "ImportError": "Error de importación",
     "FileNotFoundError": "Archivo no encontrado",
-    "ZeroDivisionError": "Error: división por cero",
+    "ZeroDivisionError": "Error división por cero",
     "RecursionError": "Error de recursión",
     "RuntimeError": "Error de ejecución",
     "MemoryError": "Error de memoria",
     "OverflowError": "Error de desbordamiento",
     "AssertionError": "Error de afirmación",
-    "NotImplementedError": "Error: no implementado",
+    "NotImplementedError": "Error no implementado",
     "StopIteration": "Detener iteración",
     "KeyboardInterrupt": "Interrupción de teclado",
     "PermissionError": "Error de permiso",
     "TimeoutError": "Error de tiempo agotado"
   },
   "stdlib": {
-    "matematicas": "math",
+    "mate": "math",
-    "sistema": "sys",
+    "sis": "sys",
-    "fecha_hora": "datetime",
+    "fechahora": "datetime",
     "tiempo": "time",
     "aleatorio": "random",
+    "aleatoria": "random",
     "colecciones": "collections",
     "ruta": "pathlib",
-    "expresion_regular": "re"
+    "er": "re"
-  }
+  },
+  "postfix_keywords": []
 }

packages/langs/ta/README.md

@@ -0,0 +1 @@
+# foreignthon-ta

packages/langs/ta/pyproject.toml

@@ -4,23 +4,15 @@ build-backend = "hatchling.build"
 
 [project]
 name = "foreignthon-ta"
-version = "0.1.0"
+version = "0.2.1"
 description = "Tamil language pack for ForeignThon."
-readme = "README.md"
+license = { text = "GPL v3" }
-license = { text = "MIT" }
 requires-python = ">=3.9"
 authors = [
-  { name = "Your Name", email = "you@example.com" }
+  { name = "Keshav Anand", email = "keshavanand.dev@gmail.com" }
 ]
 keywords = ["foreignthon", "tamil", "தமிழ்"]
-classifiers = [
+dependencies = ["foreignthon>=0.5.2"]
-  "Development Status :: 3 - Alpha",
-  "Intended Audience :: Developers",
-  "License :: OSI Approved :: MIT License",
-]
-dependencies = [
-  "foreignthon>=0.1.0",
-]
 
 [project.entry-points."foreignthon.langs"]
 ta = "foreignthon_ta"

packages/langs/ta/src/foreignthon_ta/__init__.py

@@ -0,0 +1,4 @@
+from importlib.resources import files
+
+def get_pack_path():
+    return files(__name__) / "ta.json"

packages/langs/ta/src/foreignthon_ta/ta.json

@@ -0,0 +1,141 @@
+{
+  "meta": {
+    "name": "Tamil",
+    "native_name": "தமிழ்",
+    "code": "ta",
+    "version": "0.1.0",
+    "authors": []
+  },
+  "keywords": {
+    "ஆனால்": "if",
+    "மற்றபடி": "else",
+    "இல்லைஆனால்": "elif",
+    "ஆக": "for",
+    "வரை": "while",
+    "நிரல்பாகம்": "def",
+    "கோப்பு": "class",
+    "பின்கோடு": "return",
+    "நிறுத்து": "break",
+    "தொடர்": "continue",
+    "கடந்துசெல்": "pass",
+    "முயற்சி": "try",
+    "தவிர": "except",
+    "கடைசியில்": "finally",
+    "எழுப்பு": "raise",
+    "உடன்": "with",
+    "இறக்கு": "import",
+    "இருந்து": "from",
+    "என": "as",
+    "உள்ளே": "in",
+    "ஆகும்": "is",
+    "மற்றும்": "and",
+    "அல்லது": "or",
+    "இல்லை": "not",
+    "நீக்கு": "del",
+    "உலகளாவிய": "global",
+    "உள்ளூர்சாரா": "nonlocal",
+    "உறுதிப்படுத்து": "assert",
+    "வழங்கு": "yield",
+    "காத்திரு": "await",
+    "ஒத்திசைவற்ற": "async",
+    "சிறுசார்பு": "lambda",
+    "உண்மை": "True",
+    "பொய்": "False",
+    "ஒன்றுமில்லை": "None"
+  },
+  "builtins": {
+    "பதிப்பி": "print",
+    "உள்ளீடு": "input",
+    "நீளம்": "len",
+    "வரம்பு": "range",
+    "வகை": "type",
+    "முழுஎண்": "int",
+    "தசமஎண்": "float",
+    "சரம்": "str",
+    "பட்டியல்": "list",
+    "அகராதி": "dict",
+    "கணம்": "set",
+    "தொகுப்பு": "tuple",
+    "உண்மைவகை": "bool",
+    "திற": "open",
+    "எண்ணிட": "enumerate",
+    "மேப்": "map",
+    "வடிகட்டு": "filter",
+    "வரிசைப்படுத்து": "sorted",
+    "கூட்டுத்தொகை": "sum",
+    "குறைந்தபட்சம்": "min",
+    "அதிகபட்சம்": "max",
+    "தனிமதிப்பு": "abs",
+    "சுற்று": "round",
+    "அனைத்தும்": "all",
+    "ஏதாவது": "any",
+    "அடுத்தது": "next",
+    "எண்": "id",
+    "எழுத்து": "chr",
+    "தலைகீழ்": "reversed"
+  },
+  "exceptions": {
+    "விதிவிலக்கு": "Exception",
+    "அடிப்படைவிதிவிலக்கு": "BaseException",
+    "மதிப்புபிழை": "ValueError",
+    "வகைபிழை": "TypeError",
+    "திறவுகோல்பிழை": "KeyError",
+    "குறியீட்டுபிழை": "IndexError",
+    "பண்புபிழை": "AttributeError",
+    "பெயர்பிழை": "NameError",
+    "இறக்குமதிபிழை": "ImportError",
+    "கோப்புகிடைக்கவில்லை": "FileNotFoundError",
+    "இயக்கநேரபிழை": "RuntimeError",
+    "பூஜ்யபிரிவுபிழை": "ZeroDivisionError",
+    "தொடரியல்பிழை": "SyntaxError",
+    "உறுதிப்பாட்டுபிழை": "AssertionError",
+    "நினைவகபிழை": "MemoryError",
+    "மிகைபிழை": "OverflowError",
+    "சுழல்பிழை": "RecursionError",
+    "அனுமதிபிழை": "PermissionError",
+    "நேரமுடிந்தது": "TimeoutError",
+    "கணினிவெளியேறு": "SystemExit",
+    "விசைகுறுக்கீடு": "KeyboardInterrupt"
+  },
+  "error_messages": {
+    "SyntaxError": "தொடரியல் பிழை",
+    "ValueError": "மதிப்பு பிழை",
+    "TypeError": "வகை பிழை",
+    "KeyError": "திறவுகோல் பிழை",
+    "IndexError": "குறியீட்டு பிழை",
+    "AttributeError": "பண்பு பிழை",
+    "NameError": "பெயர் பிழை",
+    "ImportError": "இறக்குமதி பிழை",
+    "FileNotFoundError": "கோப்பு கிடைக்கவில்லை",
+    "ZeroDivisionError": "பூஜ்யத்தால் வகுக்க முடியாது",
+    "RecursionError": "சுழல் பிழை",
+    "RuntimeError": "இயக்க நேர பிழை",
+    "MemoryError": "நினைவக பிழை",
+    "OverflowError": "மிகை பிழை",
+    "AssertionError": "உறுதிப்பாட்டு பிழை",
+    "PermissionError": "அனுமதி பிழை",
+    "TimeoutError": "நேரம் முடிந்தது",
+    "KeyboardInterrupt": "விசை குறுக்கீடு"
+  },
+  "stdlib": {
+    "கணிதம்": "math",
+    "கணினி": "sys",
+    "தேதிநேரம்": "datetime",
+    "நேரம்": "time",
+    "சீரற்ற": "random",
+    "தொகுப்புகள்": "collections",
+    "பாதை": "pathlib",
+    "வழக்கமொழி": "re"
+  },
+  "postfix_keywords": [
+    "if",
+    "elif",
+    "while",
+    "class",
+    "with",
+    "try",
+    "except",
+    "finally",
+    "from"
+  ]
+}