Getting Started with pyA2L
==========================
You'll find the example code `here <../pya2l/examples>`_.
Import an .a2l file to database
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: python
from pya2l import import_a2l
session = import_a2l(
"ASAP2_Demo_V161.a2l",
# encoding="latin-1" is default; override if your file differs
# progress_bar=False or loglevel="ERROR" to silence progress
)
If nothing went wrong, your working directory now contains a file named `ASAP2_Demo_V161.a2ldb`,
which is simply a `Sqlite3 `_ database file.
Unlike other ASAP2 toolkits, you are not required
to parse your `.a2l` files over and over again, which can be quite expensive.
Re-importing an existing file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
By default, re-importing a file whose `.a2ldb` already exists triggers a
confirmation prompt instead of raising an ``OSError``. To suppress the prompt
and overwrite unconditionally, pass ``force_overwrite=True``:
.. code-block:: python
from pya2l import import_a2l
session = import_a2l("ASAP2_Demo_V161.a2l", force_overwrite=True)
The CLI flag ``-f`` / ``--force-overwrite`` provides the same behaviour:
.. code-block:: bash
a2ldb-imex -i ASAP2_Demo_V161.a2l -f
Open an existing .a2ldb database
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: python
from pya2l import open_existing
session = open_existing("ASAP2_Demo_V161") # No need to specify extension .a2ldb
You may have noticed, that in both cases the return value is stored in an object named `session`:
Enter `SQLAlchemy `_!
SQLAlchemy offers, amongst other things, a powerful expression language.
Running a first database query
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: python
from pya2l import open_existing
import pya2l.model as model
session = open_existing("ASAP2_Demo_V161")
measurements = session.query(model.Measurement).order_by(model.Measurement.name).all()
for m in measurements:
print(f"{m.name:48} {m.datatype:12} 0x{m.ecu_address.address:08x}")
Yields the following output:
::
ASAM.M.ARRAY_SIZE_16.UBYTE.IDENTICAL UBYTE 0x00013a30
ASAM.M.MATRIX_DIM_16_1_1.UBYTE.IDENTICAL UBYTE 0x00013a30
ASAM.M.MATRIX_DIM_8_2_1.UBYTE.IDENTICAL UBYTE 0x00013a30
ASAM.M.MATRIX_DIM_8_4_2.UBYTE.IDENTICAL UBYTE 0x00013a30
ASAM.M.SCALAR.FLOAT32.IDENTICAL FLOAT32_IEEE 0x00013a10
ASAM.M.SCALAR.FLOAT64.IDENTICAL FLOAT64_IEEE 0x00013a14
ASAM.M.SCALAR.SBYTE.IDENTICAL SBYTE 0x00013a01
ASAM.M.SCALAR.SBYTE.LINEAR_MUL_2 SBYTE 0x00013a01
ASAM.M.SCALAR.SLONG.IDENTICAL SLONG 0x00013a0c
ASAM.M.SCALAR.SWORD.IDENTICAL SWORD 0x00013a04
ASAM.M.SCALAR.UBYTE.FORM_X_PLUS_4 UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.IDENTICAL UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_INTP_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_INTP_NO_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_NOINTP_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_NOINTP_NO_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_VERB_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.TAB_VERB_NO_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.VTAB_RANGE_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.UBYTE.VTAB_RANGE_NO_DEFAULT_VALUE UBYTE 0x00013a00
ASAM.M.SCALAR.ULONG.IDENTICAL ULONG 0x00013a08
ASAM.M.SCALAR.UWORD.IDENTICAL UWORD 0x00013a02
ASAM.M.SCALAR.UWORD.IDENTICAL.BITMASK_0008 UWORD 0x00013a20
ASAM.M.SCALAR.UWORD.IDENTICAL.BITMASK_0FF0 UWORD 0x00013a20
ASAM.M.VIRTUAL.SCALAR.SWORD.PHYSICAL SWORD 0x00000000
The classes describing an `.a2ldb` database live in `pya2l.model <../pya2l/model/__init__.py>`_, they are required to query, modify, and add model instances.
Using the Inspect API
~~~~~~~~~~~~~~~~~~~~~
The inspect API provides high-level, read-only wrappers with automatic
conversion and caching:
.. code-block:: python
from pya2l import open_existing
from pya2l.api.inspect import Project, Measurement, Characteristic
session = open_existing("ASAP2_Demo_V161")
# Navigate the project hierarchy
project = Project(session)
module = project.module[0]
print(f"Project: {project.name}")
print(f"Module: {module.name}")
# Get a measurement by name
m = Measurement.get(session, "ASAM.M.SCALAR.UBYTE.IDENTICAL")
print(f"Name: {m.name}")
print(f"Data type: {m.datatype}")
print(f"Address: 0x{m.ecuAddress:08X}")
print(f"Limits: [{m.lowerLimit}, {m.upperLimit}]")
print(f"CompuMethod: {m.compuMethod.conversionType}")
# Convert a raw ECU value to physical
raw_value = 42
phys = m.compuMethod.int_to_physical(raw_value)
print(f" {raw_value} raw → {phys} physical")
# Query all FLOAT32 measurements
float_meas = list(module.measurement.query(
lambda row: row.datatype == "FLOAT32_IEEE"
))
print(f"\nFLOAT32 measurements: {len(float_meas)}")
for fm in float_meas:
print(f" {fm.name}")
# Query characteristics by type
maps = list(module.characteristic.query(
lambda row: row.type == "MAP"
))
print(f"\nMAP characteristics: {len(maps)}")
for c in maps:
print(f" {c.name}: {c.num_axes} axes, shape={c.fnc_np_shape}")
Working with IF_DATA
~~~~~~~~~~~~~~~~~~~~
IF_DATA sections carry vendor-specific protocol information (XCP, CCP, …).
The ``if_data`` attribute on every inspect object returns an ``IfData``
instance with parsed and raw data:
.. code-block:: python
from pya2l import open_create
from pya2l.api.inspect import Module
session = open_create("xcp_demo_autodetect.a2l")
module = Module(session)
# Access the IfData dataclass
ifd = module.if_data
# Parsed structure (list of dicts)
for block in ifd.if_data_parsed:
print(block)
# Quick key look-up via flatmap
for key in ifd.flatmap:
print(f" {key}: {len(ifd.flatmap[key])} occurrence(s)")
# Raw text for debugging
for raw in ifd.if_data_raw:
print(raw.raw[:200], "...")
See :doc:`ifdata` for a comprehensive guide.
Validate and export
~~~~~~~~~~~~~~~~~~~
Basic validation:
.. code-block:: python
from pya2l import open_existing
from pya2l.api.validate import Validator
session = open_existing("ASAP2_Demo_V161")
for msg in Validator(session)():
print(msg.type.name, msg.category.name, msg.diag_code.name, "-", msg.text)
Export back to text:
.. code-block:: python
from pya2l import export_a2l
export_a2l("ASAP2_Demo_V161", "exported.a2l")
See :doc:`howto` for Excel export and other short recipes.
The test-suite found `here <../pya2l/tests/test_a2l_parser.py>`_ is a good starting point for further experimentations, because
it touches virtually every A2L element/attribute.
Next steps
~~~~~~~~~~
- :doc:`tutorial` — In-depth walkthrough of all features
- :doc:`ifdata` — Comprehensive IF_DATA guide
- :doc:`api_reference` — Full API reference with examples
- :doc:`howto` — Task-oriented quick recipes
Migrating from ``pya2l.DB``
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The ``DB`` wrapper class is **deprecated** and will be removed in a future
release. Replace each call pattern as shown below — the behaviour is identical:
.. list-table::
:header-rows: 1
:widths: 50 50
* - Old (deprecated)
- New (preferred)
* - ``DB().import_a2l("file.a2l")``
- ``import_a2l("file.a2l")``
* - ``DB().open_existing("file")``
- ``open_existing("file")``
* - ``DB().open_create("file.a2l")``
- ``open_create("file.a2l")``
* - ``DB.import_a2l(db, "file.a2l")``
- ``import_a2l("file.a2l")``
All keyword arguments (``encoding``, ``loglevel``, ``local``, ``progress_bar``,
``force_overwrite``) are available on the module-level functions.
.. code-block:: python
# Before
from pya2l import DB
session = DB().import_a2l("my.a2l", loglevel="ERROR")
# After
from pya2l import import_a2l
session = import_a2l("my.a2l", loglevel="ERROR")