pycql originally only supports the old CSW CQL dialect. But more filter languages/dialects exist:

• OGC filter encoding specification (FES) or OGC filters: http://docs.opengeospatial.org/is/09-026r2/09-026r2.html
• OGC API features/records CQL text definition and JSON encoding: http://docs.ogc.org/DRAFTS/19-079.html

As all these filter languages offer more or less the same functionality, it is envisioned to

• Create a new python package (in favor of renaming this package): pygeofilters where most of the pycql source code will be copied to
• Update the AST to accommodate the features of all languages/dialects (potentially with type-checks via pydantic)
• Implement the parsers for each language encoding/dialect

When this is done, this git repository shall be archived and redirect to pygeofilters

Running the following:

from pycql.integrations.sqlalchemy import to_filter, parse

cql_text = 'title = "foo"'
ast = parse(cql_text)

Results in the following warning:

WARNING: Couldn't write lextab module 'lextab'. [Errno 20] Not a directory: '/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/lextab.py'

The parser for BBOX demands a CRS, while in the ECQL specification this is optional:

BBOX ( Expression , Number , Number , Number , Number [ , CRS ] )

E.g. this works: BBOX(geometry,13,48,14,49,"EPSG:4326")
while this throws an error: BBOX(geometry,13,48,14,49) although it is valid according to specs.

Error: Syntax error at token RPAREN ) 25 1

pycql should not demand a CRS.

In OGC API - Records, some properties contain dashes (record-created, record-updated, keywords-codespace, etc.). The following CQL:

record-updated < "2000"

results in the following error:

  File "/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/integrations/sqlalchemy/evaluate.py", line 102, in to_filter
    return FilterEvaluator(field_mapping).to_filter(ast)
  File "/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/integrations/sqlalchemy/evaluate.py", line 33, in to_filter
    to_filter(node.lhs), to_filter(node.rhs), node.op,
  File "/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/integrations/sqlalchemy/evaluate.py", line 85, in to_filter
    to_filter(node.lhs), to_filter(node.rhs), node.op
  File "/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/integrations/sqlalchemy/filters.py", line 103, in runop
    return _op.function(lhs, rhs)
  File "/Users/tkralidi/Dev/pycsw/lib/python3.7/site-packages/pycql-0.0.8-py3.7.egg/pycql/integrations/sqlalchemy/filters.py", line 49, in <lambda>
    "-": lambda f, a: f - a,
TypeError: unsupported operand type(s) for -: 'str' and 'str'