Module plpgsql 

PL/pgSQL function bodies: typed AST, parser, and the variable binding rewriter.

Bodies are parsed with libpg_query’s PL/pgSQL parser (pg_query::parse_plpgsql), which returns the same JSON dump PostgreSQL itself produces. This module lowers that JSON into a typed AST whose embedded SQL fragments are pre-compiled into Expr / Statement values, ready for execution against the engine.

Variable references inside embedded SQL are plain column references after compilation. At execution time the interpreter rewrites them into literals through VariableResolver / bind_expr / bind_statement before handing the statement to the engine. This matches plpgsql.variable_conflict = use_variable resolution: a name that is both a PL/pgSQL variable and a column of a queried table resolves to the variable (stock PostgreSQL raises an ambiguity error instead).

Structs

PLpgSQLBlock

[DECLARE ...] BEGIN ... [EXCEPTION ...] END block.

PLpgSQLCursor

PLpgSQLCursorArgument

PLpgSQLExceptionArm

One WHEN cond [OR cond ...] THEN stmts arm of an exception section.

PLpgSQLFunction

A parsed PL/pgSQL function body: the flat datum table plus the outermost block.

PLpgSQLRowField

name -> datum slot of a row target.

PLpgSQLVar

Scalar PL/pgSQL variable (declared variable, parameter, loop counter, or an internal compiler temporary).

Enums

IntoTarget

Assignment / INTO target.

PLpgSQLDatum

One entry in the function’s flat datum table. varno / dno references inside statements index into this table.

PLpgSQLReturnValue

Value source for RETURN and RETURN NEXT. PostgreSQL 18 stores a simple datum reference in retvarno, distinct from a general SQL expression.

PLpgSQLStmt

Executable PL/pgSQL statement.

RaiseLevel

RAISE severity.

Traits

VariableResolver

Resolves routine variables while a compiled expression / statement is being specialized for one execution.

Functions

bind_expr

Rewrite an expression, substituting resolvable variable references with literals. References the resolver declines stay untouched.

bind_select

Rewrite a SELECT body, substituting resolvable variables.

bind_statement

Rewrite a full statement, substituting resolvable variables in every expression position. Statements without expression payloads pass through unchanged.

compile_expression_text

Compile a bare expression through PostgreSQL’s PL/pgSQL expression parser.

condition_sqlstate

Map a PL/pgSQL condition name to the SQLSTATE used by RAISE condition_name.

condition_sqlstates

Return every SQLSTATE matched by a PL/pgSQL exception condition.

parse_do_block

Parse a DO $$ ... $$ body by wrapping it into an anonymous void-returning function.

parse_function