Bodies of the schema-building module procedures declared in parquet_core.f90's interface block: parsing a MAML into a parquet_schema (parquet_parse_maml), building a schema from scratch (schema%init/%add_field), and the central parquet_parse_maml_lines parser, plus the private MAML-section helpers (keyarray:/DOI/depends/keywords/col_map/protected_cols) it depends on.