pglast 5.0

PostgreSQL Languages AST and statements prettifier

Author:

Lele Gaifax

Contact:

[e-mail]

License:

GNU General Public License version 3 or later

Status:

Version:

5

This is a Python 3 module that exposes the parse tree of a PostgreSQL statement (extracted by the almost standard PG parser repackaged as a standalone static library by libpg_query) as set of interconnected nodes, usually called an abstract syntax tree.

See a more detailed introduction in the documentation.

Installation

As usual, the easiest way is with pip:

$ pip install pglast

Alternatively you can clone the repository:

$ git clone https://github.com/lelit/pglast.git --recursive

and install from there:

$ pip install ./pglast

Development

There is a set of makefiles implementing the most common operations, a make help will show a brief table of contents. A comprehensive test suite, based on pytest, covers nearly 99% of the source lines.

Documentation

Latest documentation is hosted by Read the Docs at https://pglast.readthedocs.io/en/v5

Changes

Version 5

5.0 (2023-02-19)

• No changes

5.0.dev1 (2023-02-11)

• Update libpg_query to 15-4.2.0

Breaking changes

• Change the type of the ast.Float value from Decimal to str

  Using a Decimal implies potential differences in the representation of floating numbers, and already caused issues (#91 and #100) in the past, making it impossible to render, say, SELECT 0.0e1, due to the fact that Decimal('0.0e1') resolves to Decimal('0').

5.0.dev0 (2022-12-19)

• No visible changes with respect to v4, apart from the support for new/revised syntaxes of PostgreSQL 15

Breaking changes

• Target PostgreSQL 15, thanks to libpg_query 15-4.0.0

Version 4

4.1 (2022-12-19)

• Fix serialization glitches introduced by “Avoid overly abundancy of parentheses in expressions” (to be precise, by this commit)

4.0 (2022-12-12)

• Update libpg_query to final 14-3.0.0

4.0.dev0 (2022-11-24)

• Update libpg_query to 14-3.0.0

• Avoid overly abundancy of parentheses in expressions

• Prefer SELECT a FROM b LIMIT ALL to ... LIMIT NONE

Breaking changes

• Target PostgreSQL 14

• The wrapper classes used in previous versions, implemented in pglast.node, are gone: now everything works on top of the AST classes (issue #80)

• The Ancestor class is not iterable anymore: it was an internal implementation facility, now moved to a _iter_members() method

Version 3

3.17 (2022-11-04)

• Fix AlterSubscriptionStmt printer, handling “SET PUBLICATION” without options

3.16 (2022-11-03)

• Update libpg_query to 13-2.2.0

3.15 (2022-10-17)

• Produce Python 3.11 wheels (PR #108), thanks to cibuildwheel 2.11.1 and to Bastien Gandouet

3.14 (2022-08-08)

• Harden the way Visitor handle modifications to the AST (issue #107)

3.13 (2022-06-29)

• Update libpg_query to 13-2.1.2

3.12 (2022-06-19)

• Rewrite the implementation of the referenced_relations() function, that was flawed with regard to CTEs handling (issue #106), thanks to Michal Charemza for providing his own version

• Improve WithClause printer indentation

• Fix minor whitespace related issues in a few printer functions

3.11 (2022-05-29)

• Fix the Visitor class, it was ignoring nodes nested in sub-lists

• Reduce the size of the generated parser by factoring out common code into helper functions

3.10 (2022-05-11)

• Update libpg_query to 13-2.1.1 (PR #102), thanks to James Guthrie

• Produce musllinux wheels, thanks to cibuildwheel 2.5.0 (PEP 656 was actually introduced in 2.2.0)

3.9 (2022-02-24)

• Fix bug handling node containing a location field, e.g. CreateTableSpaceStmt (issue #98)

• Properly handle dereferenced array expression (issue #99)

• Avoid improper “floatification” of literal integers (issue #100)

3.8 (2021-12-28)

• Fix glitch in the AST extractor tool (issue #97)

• Add Linux AArch64 wheel build support (PR #95), thanks to odidev

• Fix type mismatch when using --remove-pg_catalog-from-functions (PR #93), thanks to Boris Zentner

3.7 (2021-10-13)

• Update libpg_query to 13-2.1.0

3.6 (2021-10-09)

• Use latest libpg_query, to fix an error parsing PLpgSQL statements (issue #88)

3.5 (2021-09-26)

• Forward the special_functions option to substream, when concatenating items (issue #89)

• Fix representation of floating point numbers without decimal digits (issue #91)

• Produce Python 3.10 wheels, thanks to cibuildwheel 2.1.2

• Update libpg_query to 13-2.0.7

• New option --remove-pg_catalog-from-functions on the command line tool (PR #90), thanks to Boris Zentner

• Implement more special functions (PR #92), thanks to Boris Zentner

3.4 (2021-08-21)

• Fix another packaging issue, that prevented recompilation from the sdist .tar.gz (issue #86), thanks to Christopher Brichford

3.3 (2021-07-04)

• Update libpg_query to 13-2.0.6

3.2 (2021-06-25)

• Effectively include libpg_query’s vendored sources (issue #82)

3.1 (2021-06-25)

• Fix packaging glitch (issue #82)

• Build wheels also for macOS

• Update libpg_query to 13-2.0.5

3.0 (2021-06-04)

• Fix glitch in the RawStream, avoiding spurious space after an open parenthesis

• Improve the Visitor class, to make it easier altering the original tree

• Properly handle nested lists in the serialization of AST Node

3.0.dev2 (2021-05-22)

• Fix bug in CreateStmt printer (issue #79)

• Make it possible to pass also concrete ast.Nodes to RawStream`

Breaking changes

• To reduce confusion, the printer module has been removed: print-specific stuff is now directly exposed by the printers subpackage while serialization classes are now in the new stream module

• The default value for the safety_belt option of the printify() function is now False

3.0.dev1 (2021-05-16)

• Fix AT_SetIdentity, AT_EnableReplicaTrig and AlterSubscriptionStmt printers

• Improve AlterTSConfigType and IntoClause printers

• New generic “visitor pattern” (issue #51) exemplified by a new referenced_relations() function (issue #66)

• Refine printing of SQL comments

• Implement AlterExtensionStmt printer

3.0.dev0 (2021-05-03)

• Expose the new pg_query_scan() function as parser.scan()

• Expose the pg_query_parse() function as parser.parse_sql_json()

• Expose the new pg_query_parse_protobuf() function as parser.parse_sql_protobuf()

• Expose the new pg_query_deparse_protobuf() function as parser.deparse_protobuf()

• Honor the catalogname of a RangeVar if present (issue #71)

• Cover almost all SQL statements, testing against the whole PostgreSQL regression suite (issue #68, PR #72 and PR #77), thanks to Ronan Dunklau and Hong Cheng

• New rudimentary support for the preserve comments feature (issue #23)

Breaking changes

• Target PostgreSQL 13

• The pglast.parser module exposes all libpg_query entry points, even the new pg_query_deparse_protobuf() function that is basically equivalent to RawStream-based printer

• The split() function is now based on the lower level pg_query_split_with_xxx() functions

• The parse_sql() function returns native Python objects, not a JSON string as before: all PG nodes are now represented by subclasses of pglast.ast.Node, without exception, even Expr and Value are there. The latter impacts on pglast.node.Scalar: for example it now may contains a ast.Integer instance instead of a Python int

• The pgpp --parse-tree output is a pprint represention of the AST, not a JSON string as before

• The ParseError exception does not expose the location as an instance member anymore, although its still there, as the second argument (ie .args[1]); furthermore, its value now corresponds to the index in the original Unicode string, instead of the offset in the UTF-8 representation passed to the underlying C function

Version 2

2.0.dev3 (2021-02-20)

• Handle INCLUDE clause in IndexStmt (PR #67), thanks to Ronan Dunklau

2.0.dev2 (2020-10-24)

• Merge new fingerprint functionality from v1 (i.e. master) branch

2.0.dev1 (2020-09-26)

• Require Python 3.6 or greater

• Handle ALTER TYPE .. RENAME VALUE in AlterEnumStmt (PR #52), thanks to Ronan Dunklau

• Add support for Create / Alter / Drop PROCEDURE (PR #48), thanks to Ronan Dunklau

• Use Ronan’s fork of libpg_query, targeting PostgreSQL 12.1 (PR #36)

• Change get_postgresql_version() to return a (major, minor) tuple (issue #38)

• Handle ALTER TABLE ... ALTER COLUMN ... SET STORAGE ...

• Handle PG12 materialized CTEs (issue #57)

• Support column numbers in ALTER INDEX (PR #58), thanks to Ronan Dunklau

• Handle SET LOGGED and SET UNLOGGED in ALTER TABLE (PR #59), thanks to Ronan Dunklau

• Handle ALTER TYPE ... RENAME (PR #62), , thanks to Ronan Dunklau

Version 1

1.18 (2021-06-01)

• Fix exclusion constraint printer (issue #81)

1.17 (2021-02-20)

• Fix the generic case in the RenameStmt printer

1.16 (2021-02-20)

• Promote to the stable state

• Move the job of building and uploading binary wheels from TravisCI to GitHub Actions

1.15 (2021-02-19)

• Fix IF EXISTS variant of RenameStmt printer (PR #70), thanks to Jonathan Mortensen

• Update libpg_query to 10-1.0.5

1.14 (2020-10-24)

• Produce Python 3.9 wheels, thanks to cibuildwheel 1.6.3

• Expose the libpg_query’s fingerprint functionality (PR #64), thanks to Yiming Wang

1.13 (2020-09-26)

• Handle SELECT FROM foo

1.12 (2020-06-08)

• Double quote column names in the TYPE_FUNC_NAME_KEYWORDS set (issue #55)

• Possibly wrap SELECT in UNION/INTERSECT between parens, when needed (issue #55)

1.11 (2020-05-08)

• Fix A_Expr printer, when lexpr is missing (PR #54), thanks to Aiham

• Support DISABLE ROW LEVEL SECURITY in AlterTableCmd (PR #49), thanks to Ronan Dunklau

• Implement CreateOpClassStmt printer (PR #47), thanks to Ronan Dunklau

1.10 (2020-01-25)

• Fix collation name printer (PR #44), thanks to Ronan Dunklau

• Implement CreatePLangStmt printer (PR #42), thanks to Bennie Swart

• Fix privileges printer (PR #41), thanks to Bennie Swart

• Handle TRUNCATE event in CreateTrigStmt printer (PR #40), thanks to Bennie Swart

• Fix function body dollar quoting (PR #39), thanks to Bennie Swart

1.9 (2019-12-20)

• Prettier INSERT representation

1.8 (2019-12-07)

• Prettier CASE representation

• New option to emit a semicolon after the last statement (issue #24)

1.7 (2019-12-01)

• Implement NotifyStmt printer

• Implement RuleStmt printer, thanks to Gavin M. Roy for his PR #28

• Fix RenameStmt, properly handling object name

• Produce Python 3.8 wheels, thanks to cibuildwheel 1.0.0

• Support ALTER TABLE RENAME CONSTRAINT (PR #35), thanks to Ronan Dunklau

1.6 (2019-09-04)

• Fix issue with boolean expressions precedence (issue #29)

• Implement BitString printer

• Support LEAKPROOF option (PR #31), thanks to Ronan Dunklau

• Support DEFERRABLE INITIALLY DEFERRED option (PR #32), thanks to Ronan Dunklau

1.5 (2019-06-04)

• Fix issue with RETURNS SETOF functions, a more general solution than the one proposed by Ronan Dunklau (PR #22)

• Allow more than one empty line between statements (PR #26), thanks to apnewberry

1.4 (2019-04-06)

• Fix wrap of trigger’s WHEN expression (issue #18)

• Support for variadic functions (PR #19), thanks to Ronan Dunklau

• Support ORDER / LIMIT / OFFSET for set operations (PR #20), thanks to Ronan Dunklau

• Implement ConstraintsSetStmt and improve VariableSetStmt printers

1.3 (2019-03-28)

• Support CROSS JOIN and timezone modifiers on time and timestamp datatypes (PR #15), thanks to Ronan Dunklau

• Many new printers and several enhancements (PR #14), thanks to Ronan Dunklau

• Expose the package version as pglast.__version__ (issue #12)

1.2 (2019-02-13)

• Implement new split() function (see PR #10)

• Implement BooleanTest printer (issue #11)

1.1 (2018-07-20)

• No visible changes, but now PyPI carries binary wheels for Python 3.7.

1.0 (2018-06-16)

Important

The name of the package has been changed from pg_query to pglast, to satisfy the request made by the author of libpg_query in issue #9.

This affects both the main repository on GitHub, that from now on is https://github.com/lelit/pglast, and the ReadTheDocs project that hosts the documentation, http://pglast.readthedocs.io/en/latest/.

I’m sorry for any inconvenience this may cause.

0.28 (2018-06-06)

• Update libpg_query to 10-1.0.2

• Support the ‘?’-style parameter placeholder variant allowed by libpg_query (details)

0.27 (2018-04-15)

• Prettier JOINs representation, aligning them with the starting relation

0.26 (2018-04-03)

• Fix cosmetic issue with ANY() and ALL()

0.25 (2018-03-31)

• Fix issue in the safety belt check performed by pgpp (issue #4)

0.24 (2018-03-02)

• Implement Null printer

0.23 (2017-12-28)

• Implement some other DDL statements printers

• New alternative style to print comma-separated-values lists, activated by a new --comma-at-eoln option on pgpp

0.22 (2017-12-03)

• Implement TransactionStmt and almost all DROP xxx printers

0.21 (2017-11-22)

• Implement NamedArgExpr printer

• New alternative printers for a set of special functions, activated by a new --special-functions option on pgpp (issue #2)

0.20 (2017-11-21)

• Handle special de-reference (A_Indirection) cases

0.19 (2017-11-16)

• Fix serialization of column labels containing double quotes

• Fix corner issues surfaced implementing some more DDL statement printers

0.18 (2017-11-14)

• Fix endless loop due to sloppy conversion of command line option

• Install the command line tool as pgpp

0.17 (2017-11-12)

• Rename printers.sql to printers.dml (backward incompatibility)

• List printer functions in the documentation, referencing the definition of related node type

• Fix inconsistent spacing in JOIN condition inside a nested expression

• Fix representation of unbound arrays

• Fix representation of interval data type

• Initial support for DDL statements

• Fix representation of string literals containing single quotes

0.16 (2017-10-31)

• Update libpg_query to 10-1.0.0

0.15 (2017-10-12)

• Fix indentation of boolean expressions in SELECT’s targets (issue #3)

0.14 (2017-10-09)

• Update to latest libpg_query’s 10-latest branch, targeting PostgreSQL 10.0 final

0.13 (2017-09-17)

• Fix representation of subselects requiring surrounding parens

0.12 (2017-08-22)

• New option --version on the command line tool

• Better enums documentation

• Release the GIL while calling libpg_query functions

0.11 (2017-08-11)

• Nicer indentation for JOINs, making OUTER JOINs stand out

• Minor tweaks to lists rendering, with less spurious whitespaces

• New option --no-location on the command line tool

0.10 (2017-08-11)

• Support Python 3.4 and Python 3.5 as well as Python 3.6

0.9 (2017-08-10)

• Fix spacing before the $ character

• Handle type modifiers

• New option --plpgsql on the command line tool, just for fun

0.8 (2017-08-10)

• Add enums subpackages to the documentation with references to their related headers

• New compact_lists_margin option to produce a more compact representation when possible (see issue #1)

0.7 (2017-08-10)

• Fix sdist including the Sphinx documentation

0.6 (2017-08-10)

• New option --parse-tree on the command line tool to show just the parse tree

• Sphinx documentation, available online

0.5 (2017-08-09)

• Handle some more cases when a name must be double-quoted

• Complete the serialization of the WindowDef node, handling its frame options

0.4 (2017-08-09)

• Expose the actual PostgreSQL version the underlying libpg_query libray is built on thru a new get_postgresql_version() function

• New option safety_belt for the prettify() function, to protect the innocents

• Handle serialization of CoalesceExpr and MinMaxExpr

0.3 (2017-08-07)

• Handle serialization of ParamRef nodes

• Expose a prettify() helper function

0.2 (2017-08-07)

• Test coverage at 99%

• First attempt at automatic wheel upload to PyPI, let’s see…

0.1 (2017-08-07)

• First release (“Hi daddy!”, as my soul would tag it)