Module visit_mut

Traversal of a mutable AST.

This module provides a VisitMut trait that is like the Visit trait but operates on a mutable borrow, rather than an immutable borrow, of the syntax tree.

Each method of the VisitMut trait is a hook that can be overridden to customize the behavior when visiting the corresponding type of node. By default, every method recursively visits the substructure of the input by invoking the right visitor method of each of its fields.

pub trait VisitMut<'ast, T: AstInfo> {
    /* ... */

    fn visit_function_mut(&mut self, node: &'ast mut Function<T>) {
        visit_function_mut(self, node);
    }

    /* ... */
}

pub fn visit_function_mut<'ast, V, T: AstInfo>(visitor: &mut V, node: &'ast mut Function<T>)
where
    V: VisitMut<'ast, T> + ?Sized,
{
    visitor.visit_item_name_mut(&mut node.name);
    visitor.visit_function_args_mut(&mut node.args);
    if let Some(filter) = &mut node.filter {
        visitor.visit_expr_mut(&mut *filter);
    }
    if let Some(over) = &mut node.over {
        visitor.visit_window_spec_mut(over);
    }
}

Examples

This visitor removes parentheses from expressions.

use std::error::Error;

use mz_sql_parser::ast::{AstInfo, Expr};
use mz_sql_parser::ast::visit_mut::{self, VisitMut};

struct RemoveParens;

impl<'a, T: AstInfo> VisitMut<'a, T> for RemoveParens {
    fn visit_expr_mut(&mut self, expr: &'a mut Expr<T>) {
        visit_mut::visit_expr_mut(self, expr);
        if let Expr::Nested(e) = expr {
            *expr = (**e).clone();
        }
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    let sql = "(a + ((b))) + c";
    let mut expr = mz_sql_parser::parser::parse_expr(sql.into())?;
    RemoveParens.visit_expr_mut(&mut expr);
    let expected = mz_sql_parser::parser::parse_expr("a + b + c".into())?;
    assert_eq!(expr, expected);
    Ok(())
}

The VisitMutNode trait is implemented for every node in the AST and can be used to write generic functions that apply a VisitMut implementation to any node in the AST.

Implementation notes

This module is automatically generated by the crate’s build script. Changes to the AST will be automatically propagated to the visitor.

This approach to AST visitors is inspired by the syn crate. These module docs are directly derived from the syn::visit_mut module docs.

Traits

VisitMut

VisitMutNode

Functions

visit_abbreviated_grant_or_revoke_statement_mut

visit_abbreviated_grant_statement_mut

visit_abbreviated_revoke_statement_mut

visit_alter_cluster_action_mut

visit_alter_cluster_statement_mut

visit_alter_connection_action_mut

visit_alter_connection_option_mut

visit_alter_connection_option_name_mut

visit_alter_connection_statement_mut

visit_alter_default_privileges_statement_mut

visit_alter_index_action_mut

visit_alter_index_statement_mut

visit_alter_network_policy_statement_mut

visit_alter_object_rename_statement_mut

visit_alter_object_swap_statement_mut

visit_alter_owner_statement_mut

visit_alter_retain_history_statement_mut

visit_alter_role_option_mut

visit_alter_role_statement_mut

visit_alter_secret_statement_mut

visit_alter_set_cluster_statement_mut

visit_alter_sink_action_mut

visit_alter_sink_statement_mut

visit_alter_source_action_mut

visit_alter_source_add_subsource_option_mut

visit_alter_source_add_subsource_option_name_mut

visit_alter_source_statement_mut

visit_alter_system_reset_all_statement_mut

visit_alter_system_reset_statement_mut

visit_alter_system_set_statement_mut

visit_alter_table_add_column_statement_mut

visit_as_of_mut

visit_assignment_mut

visit_avro_doc_on_mut

visit_avro_schema_mut

visit_avro_schema_option_mut

visit_avro_schema_option_name_mut

visit_catalog_name_mut

visit_close_statement_mut

visit_cluster_alter_option_mut

visit_cluster_alter_option_name_mut

visit_cluster_alter_option_value_mut

visit_cluster_alter_until_ready_option_mut

visit_cluster_alter_until_ready_option_name_mut

visit_cluster_feature_mut

visit_cluster_feature_name_mut

visit_cluster_name_mut

visit_cluster_option_mut

visit_cluster_option_name_mut

visit_cluster_schedule_option_value_mut

visit_column_def_mut

visit_column_name_mut

visit_column_option_def_mut

visit_column_option_mut

visit_column_reference_mut

visit_column_versioned_mut

visit_comment_object_type_mut

visit_comment_statement_mut

visit_commit_statement_mut

visit_connection_default_aws_privatelink_mut

visit_connection_option_mut

visit_connection_option_name_mut

visit_continual_task_option_mut

visit_continual_task_option_name_mut

visit_continual_task_stmt_mut

visit_copy_direction_mut

visit_copy_option_mut

visit_copy_option_name_mut

visit_copy_relation_mut

visit_copy_statement_mut

visit_copy_target_mut

visit_create_cluster_replica_statement_mut

visit_create_cluster_statement_mut

visit_create_connection_option_mut

visit_create_connection_option_name_mut

visit_create_connection_statement_mut

visit_create_connection_type_mut

visit_create_continual_task_statement_mut

visit_create_continual_task_sugar_mut

visit_create_database_statement_mut

visit_create_index_statement_mut

visit_create_materialized_view_statement_mut

visit_create_network_policy_statement_mut

visit_create_role_statement_mut

visit_create_schema_statement_mut

visit_create_secret_statement_mut

visit_create_sink_connection_mut

visit_create_sink_option_mut

visit_create_sink_option_name_mut

visit_create_sink_statement_mut

visit_create_source_connection_mut

visit_create_source_option_mut

visit_create_source_option_name_mut

visit_create_source_statement_mut

visit_create_subsource_option_mut

visit_create_subsource_option_name_mut

visit_create_subsource_statement_mut

visit_create_table_from_source_statement_mut

visit_create_table_statement_mut

visit_create_type_as_mut

visit_create_type_list_option_mut

visit_create_type_list_option_name_mut

visit_create_type_map_option_mut

visit_create_type_map_option_name_mut

visit_create_type_statement_mut

visit_create_view_statement_mut

visit_create_webhook_source_body_mut

visit_create_webhook_source_check_mut

visit_create_webhook_source_check_options_mut

visit_create_webhook_source_filter_header_mut

visit_create_webhook_source_header_mut

visit_create_webhook_source_include_headers_mut

visit_create_webhook_source_map_header_mut

visit_create_webhook_source_secret_mut

visit_create_webhook_source_statement_mut

visit_csr_config_option_mut

visit_csr_config_option_name_mut

visit_csr_connection_avro_mut

visit_csr_connection_mut

visit_csr_connection_protobuf_mut

visit_csr_seed_avro_mut

visit_csr_seed_protobuf_mut

visit_csr_seed_protobuf_schema_mut

visit_csv_columns_mut

visit_cte_block_mut

visit_cte_id_mut

visit_cte_mut

visit_cte_mut_rec_column_def_mut

visit_cte_mut_rec_mut

visit_data_type_mut

visit_database_name_mut

visit_date_time_field_mut

visit_deallocate_statement_mut

visit_declare_statement_mut

visit_deferred_item_name_mut

visit_delete_statement_mut

visit_discard_statement_mut

visit_discard_target_mut

visit_distinct_mut

visit_doc_on_identifier_mut

visit_doc_on_schema_mut

visit_drop_objects_statement_mut

visit_drop_owned_statement_mut

visit_execute_statement_mut

visit_explain_analyze_computation_property_mut

visit_explain_analyze_property_mut

visit_explain_analyze_statement_mut

visit_explain_format_mut

visit_explain_plan_option_mut

visit_explain_plan_option_name_mut

visit_explain_plan_statement_mut

visit_explain_pushdown_statement_mut

visit_explain_sink_schema_for_mut

visit_explain_sink_schema_statement_mut

visit_explain_stage_mut

visit_explain_timestamp_statement_mut

visit_explainee_mut

visit_expr_mut

visit_external_reference_export_mut

visit_external_references_mut

visit_fetch_direction_mut

visit_fetch_option_mut

visit_fetch_option_name_mut

visit_fetch_statement_mut

visit_format_mut

visit_format_specifier_mut

visit_function_args_mut

visit_function_mut

visit_grant_privileges_statement_mut

visit_grant_role_statement_mut

visit_grant_target_all_specification_mut

visit_grant_target_specification_inner_mut

visit_grant_target_specification_mut

visit_homogenizing_function_mut

visit_ident_error_mut

visit_ident_mut

visit_if_exists_behavior_mut

visit_index_option_mut

visit_index_option_name_mut

visit_insert_source_mut

visit_insert_statement_mut

visit_inspect_shard_statement_mut

visit_interval_value_mut

visit_is_expr_construct_mut

visit_item_name_mut

visit_join_constraint_mut

visit_join_mut

visit_join_operator_mut

visit_kafka_broker_aws_privatelink_mut

visit_kafka_broker_aws_privatelink_option_mut

visit_kafka_broker_aws_privatelink_option_name_mut

visit_kafka_broker_mut

visit_kafka_broker_tunnel_mut

visit_kafka_sink_config_option_mut

visit_kafka_sink_config_option_name_mut

visit_kafka_sink_key_mut

visit_kafka_source_config_option_mut

visit_kafka_source_config_option_name_mut

visit_key_constraint_mut

visit_limit_mut

visit_load_generator_mut

visit_load_generator_option_mut

visit_load_generator_option_name_mut

visit_map_entry_mut

visit_materialized_view_option_mut

visit_materialized_view_option_name_mut

visit_mut_rec_block_mut

visit_mut_rec_block_option_mut

visit_mut_rec_block_option_name_mut

visit_my_sql_config_option_mut

visit_my_sql_config_option_name_mut

visit_named_plan_mut

visit_nested_statement_mut

visit_network_policy_name_mut

visit_network_policy_option_mut

visit_network_policy_option_name_mut

visit_network_policy_rule_definition_mut

visit_network_policy_rule_option_mut

visit_network_policy_rule_option_name_mut

visit_notice_severity_mut

visit_object_name_mut

visit_object_type_mut

visit_op_mut

visit_order_by_expr_mut

visit_pg_config_option_mut

visit_pg_config_option_name_mut

visit_prepare_statement_mut

visit_privilege_mut

visit_privilege_specification_mut

visit_protobuf_schema_mut

visit_qualified_replica_mut

visit_query_mut

visit_raise_statement_mut

visit_reader_schema_selection_strategy_mut

visit_reassign_owned_statement_mut

visit_refresh_at_option_value_mut

visit_refresh_every_option_value_mut

visit_refresh_option_value_mut

visit_replica_definition_mut

visit_replica_option_mut

visit_replica_option_name_mut

visit_reset_variable_statement_mut

visit_revoke_privileges_statement_mut

visit_revoke_role_statement_mut

visit_role_attribute_mut

visit_role_name_mut

visit_rollback_statement_mut

visit_schema_mut

visit_schema_name_mut

visit_select_item_mut

visit_select_mut

visit_select_option_mut

visit_select_option_name_mut

visit_select_statement_mut

visit_set_expr_mut

visit_set_operator_mut

visit_set_role_var_mut

visit_set_transaction_statement_mut

visit_set_variable_statement_mut

visit_set_variable_to_mut

visit_set_variable_value_mut

visit_show_columns_statement_mut

visit_show_create_cluster_statement_mut

visit_show_create_connection_statement_mut

visit_show_create_index_statement_mut

visit_show_create_materialized_view_statement_mut

visit_show_create_sink_statement_mut

visit_show_create_source_statement_mut

visit_show_create_table_statement_mut

visit_show_create_view_statement_mut

visit_show_object_type_mut

visit_show_objects_statement_mut

visit_show_statement_filter_mut

visit_show_statement_mut

visit_show_variable_statement_mut

visit_sink_envelope_mut

visit_source_envelope_mut

visit_source_error_policy_mut

visit_source_include_metadata_mut

visit_sql_server_config_option_mut

visit_sql_server_config_option_name_mut

visit_start_transaction_statement_mut

visit_statement_mut

visit_subscribe_option_mut

visit_subscribe_option_name_mut

visit_subscribe_output_mut

visit_subscribe_relation_mut

visit_subscribe_statement_mut

visit_subscript_position_mut

visit_system_object_type_mut

visit_table_alias_mut

visit_table_constraint_mut

visit_table_factor_mut

visit_table_from_source_columns_mut

visit_table_from_source_option_mut

visit_table_from_source_option_name_mut

visit_table_option_mut

visit_table_option_name_mut

visit_table_with_joins_mut

visit_target_role_specification_mut

visit_transaction_access_mode_mut

visit_transaction_isolation_level_mut

visit_transaction_mode_mut

visit_unresolved_database_name_mut

visit_unresolved_item_name_mut

visit_unresolved_object_name_mut

visit_unresolved_schema_name_mut

visit_update_statement_mut

visit_validate_connection_statement_mut

visit_value_error_mut

visit_value_mut

visit_values_mut

visit_version_mut

visit_view_definition_mut

visit_window_frame_bound_mut

visit_window_frame_mut

visit_window_frame_units_mut

visit_window_spec_mut

visit_with_option_value_mut