Add AST-based SQL transpiler for PostgreSQL to DuckDB conversion #34
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Replace regex-based query rewriting with proper AST-based transpilation using pg_query_go (PostgreSQL's C parser via CGO). This provides: - Proper handling of string literals (won't rewrite 'pg_catalog' in strings) - Type mappings: JSONB→JSON, BYTEA→BLOB, INET→TEXT, etc. - Function mappings: array_agg→list, string_to_array→string_split, etc. - Operator compatibility for JSON and regex operators - ON CONFLICT (upsert) syntax support - DDL constraint stripping for DuckLake mode - SET/SHOW command handling with 70+ ignored parameters The transpiler package applies a pipeline of transforms to the parsed AST: - PgCatalogTransform: pg_catalog.* references - TypeMappingTransform: PostgreSQL→DuckDB type conversions - TypeCastTransform: ::regtype→::VARCHAR - FunctionTransform: 50+ function mappings - OperatorTransform: operator compatibility - VersionTransform: version() replacement - SetShowTransform: SET/SHOW command syntax - OnConflictTransform: upsert handling - DDLTransform: constraint stripping (DuckLake mode) - PlaceholderTransform: $1→? conversion 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Shows what query is actually executed after transpilation, helping debug PostgreSQL to DuckDB conversion issues. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Summary
pg_query_go(PostgreSQL's C parser via CGO)Changes
New
transpiler/package with transform pipeline:PgCatalogTransform: Rewritespg_catalog.*references to local viewsTypeMappingTransform: Converts PostgreSQL types (JSONB→JSON, BYTEA→BLOB, INET→TEXT, etc.)TypeCastTransform: Handles type casts (::regtype → ::VARCHAR)FunctionTransform: Maps 50+ PostgreSQL functions (array_agg→list, string_to_array→string_split, etc.)OperatorTransform: Handles JSON and regex operator compatibilityVersionTransform: Replacesversion()with PostgreSQL-compatible stringSetShowTransform: Handles SET/SHOW command syntax with 70+ ignored parametersOnConflictTransform: Handles ON CONFLICT (upsert) syntaxDDLTransform: Strips constraints for DuckLake modePlaceholderTransform: Converts $1, $2 → ? for extended query protocolBenefits over regex approach:
'pg_catalog'inside strings)Test plan
🤖 Generated with Claude Code