@hackage / postgresql-syntax

v0.5.0.2

Non-breaking

• PostgresqlSyntax.Algebra's LeftRecursion base ext item class (internal-library-only, not part of the public PostgresqlSyntax API) is now a single-method Extends base ext — drops the unread item type parameter: extension/applyExtension/foldExtensions are gone in favor of one parseExtensions method; nonRecursiveParser → parseBase; parseLeftRecursive → parseMaybeExtended; leftRecursionProperties → extendedByProperties. JoinedTableExtension is deleted (#33).
• TableRef.hs and FuncApplicationParams.hs now have explicit export lists, exporting only their types and instances (#30).

Fixes

• Fixed the parsed tree shape of UNION/INTERSECT/EXCEPT chains to match Postgres's actual associativity and precedence (gram.y's %left UNION EXCEPT / %left INTERSECT, INTERSECT binding tighter): a EXCEPT b EXCEPT c now nests left instead of right, and a INTERSECT b UNION c now roots at UNION instead of INTERSECT. Rendered text is unaffected; only SimpleSelect's parsed/canonical tree shape for such chains changes (#30).
• Fixed a further associativity bug in the same fold: a run of two or more consecutive INTERSECTs (e.g. a INTERSECT b INTERSECT c) nested right instead of left, contradicting gram.y's %left INTERSECT. Parsed/canonical tree shape changes for such chains; rendered text is unaffected (#34).
• Fixed InsertRest misparsing parenthesized VALUES/SELECT as a column list (#35).

v0.5.0.1

Fixes

• Added doc-files to the .cabal-file. README.md, LICENSE and CHANGELOG.md.

v0.5.0.0

Breaking

• IsAst class methods parser/toTextBuilder now take a Settings parameter to control parse/render options (e.g. nullability ? markers). Migration: parse x -> parse mempty x, toText x -> toText mempty x, parseWithPosError x -> parseWithPosError mempty x. New public module PostgresqlSyntax.Settings provides the Settings type and the nullabilityMarkers constructor.
• Nullability ? markers in Typename are now opt-in via nullabilityMarkers True. In standard mode (mempty) they are not recognized - both flags parse as False and a literal ? in their position is a parse error. Markers no longer accept a preceding space: int ? -> int?. Extended mode gives up one spelling of real Postgres: x::jsonb? 'b' (unspaced jsonb key-existence operator); use x::jsonb ? 'b' or jsonb_exists(x, 'b').
• Removed PostgresqlSyntax.Parsing and PostgresqlSyntax.Rendering. Every type's parser and renderer are now the parser/toTextBuilder methods of its IsAst instance (exported from PostgresqlSyntax), and the top-level entry points moved to the PostgresqlSyntax module: Parsing.run/.runWithPosError became PostgresqlSyntax.parse/.parseWithPosError, generalized to work over any IsAst type rather than taking an explicit parser argument.
• PostgresqlSyntax.KeywordSet and PostgresqlSyntax.Validation are no longer part of the public API surface.
• Several former type aliases are now distinct ADTs/newtypes instead of bare Either/Maybe/primitive aliases: SelectStmt, SelectClause, ExplicitRow, and the primitive-wrapper newtypes Sconst, Bconst, Xconst, Iconst, Fconst, Op, OptVarying, Timezone, IntervalSecond, OptOrdinality. Code that pattern-matched these as Either/Maybe/Text/Bool directly needs to match on the new constructors instead.
• Removed the SuffixQualOpAExpr constructor of AExpr. It modelled the postfix operator production (a_expr qual_Op), which Postgres removed in version 14 - x OPERATOR(pg_catalog.+#) is a syntax error in every supported server version, so the parser no longer accepts it and the renderer can no longer emit it. Code pattern-matching or constructing SuffixQualOpAExpr needs to drop those cases. This also removes a family of round-trip failures: the rendering <operand> <operator> left the operator without a right-hand side, so reparsing swallowed whatever keyword followed (PRECEDING, FOLLOWING, ROWS, an implicit column alias, or - in the postfix case specifically - the ? of the Typename nullability extension) as its operand. Only the postfix-triggered ? swallow is fixed by this; Op "?" colliding with the nullability extension as a binary operator is a separate, still-open issue.

Fixes

• Fix the AExpr/BExpr renderers (and related expression renderers) being precedence-naive: operators were concatenated without parenthesization, so a non-canonical but valid AST (e.g. (NOT x) - y) could render to SQL that re-parses to a different tree (NOT (x - y)). Renderers now parenthesize based on operator precedence, making render -> parse round-trip safe for the full value space of each type, not just parser-canonical trees.

v0.4.5.0

Non-breaking

• Derive Data for every AST type in PostgresqlSyntax.Ast (#6). Enables generic (SYB-style) traversals and transformations over the syntax tree, e.g. for expression normalization.
• Add parseWithSourcePosError, like parseWithPosError but pairing each error with a Text.Megaparsec.SourcePos instead of a raw Int byte offset, so callers (e.g. hasql-th, see nikita-volkov/hasql-th#35) can report line/column positions without recomputing them from the input.

v0.4.4.0

Fixes

• Fix parsing time growing exponentially with the nesting depth of an expression (#8). Inputs as small as ((((((((((((a + b)))))))))))) previously did not finish parsing; they now parse in well under a millisecond. Three grammar alternatives each parsed the content of a parenthesised group before discovering they did not apply, tripling the work per level of nesting; they are now left-factored so each group is parsed once. Parsing time is linear in input size, with a quadratic term in nesting depth alone (1000 characters of pure nesting take about a second; realistic input is unaffected).

Non-breaking

• Redundant parentheses around a sub-select now parse to a canonical shape. ((select 1)) produces WithParensSelectWithParens; the equivalent NoParensSelectWithParens of a SelectNoParens carrying nothing but that same parenthesised select is no longer produced. The two rendered identically, so this only affects which of two equivalent trees you get back. Trees that carry a set operation, sort clause, limit or locking clause around the parenthesised select are unaffected.

v0.4.3.2

Fixes

• Fix keyword error reporting under megaparsec >=9.8 (#20)
• Fix OFFSET/aExpr round-trip failure for OPERATOR(...) prefix (#11, #22)
• Fix hedgehog generator for type_function_name to use its own keyword set