support restoring SQL text from a AST tree

[zier-one]

See: Proposal 中文教程

Our main work is in pingcap/parser/ast.
Most of ast.Nodes are in pingcap/parser/ast(Others are in pingcap/tidb/types).

We regard each ast.Node as a subtask, and we can complete one or several subtasks as a PR.
Considering that some ast.Node depends on another ast.Node, we divide sub-tasks into five stages.

Test

We believe that a Restore() function is correct when the SQL text it outputs can be parsed successfully
and the generated AST is equal to the original AST.

See: RunTest and RunRestoreTest

Some ast.Node can't be restored to a complete SQL text, such as an ast.ExprNode.
To test them, we can construct a complete SQL text.

See: expressions_test.go

There are examples which include complete implementation and test:
parser#71

Sub tasks list:

Stage One:

• ast/expressions.go: ColumnName @leoppro ast: implement Restore of ColunmNameExpr parser#63
• ast/expressions.go: ColumnNameExpr @leoppro ast: implement Restore of ColunmNameExpr parser#63
• ast/expressions.go: UnaryOperationExpr @leoppro *: support AST to SQL text parser#56
• ast/expressions.go: IsNullExpr @lovewin99 parser: ast/expressions.go: IsNullExpr parser#72
• ast/expressions.go: BetweenExpr @haplone parser: implement Restore for BetweenExpr parser#71
• ast/expressions.go: BinaryOperationExpr @haplone parser: implement Restore for BinaryOperation, WhenClause, CaseExpr and ParenthesesExpr parser#81
• ast/expressions.go: WhenClause @haplone parser: implement Restore for BinaryOperation, WhenClause, CaseExpr and ParenthesesExpr parser#81
• ast/expressions.go: CaseExpr @haplone parser: implement Restore for BinaryOperation, WhenClause, CaseExpr and ParenthesesExpr parser#81
• ast/expressions.go: ParenthesesExpr @haplone parser: implement Restore for BinaryOperation, WhenClause, CaseExpr and ParenthesesExpr parser#81
• ast/expressions.go: DefaultExpr @exialin parser: implement Restore for DefaultExpr parser#84
• ast/expressions.go: PatternLikeExpr @hanchuanchuan parser: implement Restore for PatternLikeExpr parser#89
• ast/expressions.go: IsTruthExpr @knarfeh parser: Implement Restore for IsTruthExpr parser#90
• ast/expressions.go: VariableExpr @exialin parser: implement Restore for VariableExpr parser#87
• ast/expressions.go: ValuesExpr @exialin parser: implement Restore for ValuesExpr parser#99
• ast/expressions.go: PatternRegexpExpr @kangkaisen parser: implement Restore for PatternRegexpExpr parser#96
• ast/expressions.go: MaxValueExpr @tony612 parser: implement Restore for MaxValueExpr parser#108
• ast/expressions.go: RowExpr @o-oops parser: implement Restore for RowExpr parser#113
• ast/expressions.go: PatternInExpr @tony612 parser: implement Restore for PatternInExpr parser#92
• ast/expressions.go: PositionExpr @exialin parser: implement Restore for PositionExpr, ByItem and GroupByClause parser#125
• ast/functions.go: FuncCallExpr @buzzers parser: implement Restore for FuncCallExpr and AggregateFuncExpr parser#102
• ast/functions.go: FuncCastExpr @buzzers parser: implement Restore for FuncCallExpr and AggregateFuncExpr parser#102
• ast/functions.go: AggregateFuncExpr @buzzers parser: implement Restore for FuncCallExpr and AggregateFuncExpr parser#102
• ast/functions.go: WindowFuncExpr @exialin parser: implement Restore for FrameClause, PartitionByClause, WindowSpec and WindowFuncExpr parser#143
• ast/expressions.go: ExistsSubqueryExpr @SwanSpouse parser: implement Restore for ExistsSubqueryExpr parser#126
• ast/expressions.go: SubqueryExpr @AndrewDi parser: implement Restore for SelectStmt parser#153
• ast/expressions.go: CompareSubqueryExpr @AndrewDi parser: implement Restore for SelectStmt parser#153
• tidb/types/parser_driver/value_expr.go: ValueExpr @leoppro value_expr: add charset value for string expr #9302

Stage Two:

• ast/ddl.go: DatabaseOption @leoppro *: support AST to SQL text parser#56
• ast/dml.go: TableName @feloxx parser: implement Restore for TableName parser#73
• ast/ddl.go: IndexOption @feloxx parser: implement Restore for IndexOption parser#88
• ast/dml.go: Limit @huachaohuang parser: implement Restore for Limit parser#100
• ast/ddl.go: TableToTable @tony612 parser: implement Restore for TableToTable parser#109
• ast/dml.go: WildCardField @exialin parser: implement Restore for WildCardField, SelectField and FieldList parser#118
• ast/dml.go: SelectField @exialin parser: implement Restore for WildCardField, SelectField and FieldList parser#118
• ast/dml.go: FieldList @exialin parser: implement Restore for WildCardField, SelectField and FieldList parser#118
• ast/ddl.go: IndexColName @feloxx parser: implement Restore for IndexColName parser#91
• ast/ddl.go: OnDeleteOpt @feloxx parser: implement Restore for OnDeleteOpt And OnUpdateOpt parser#98
• ast/ddl.go: OnUpdateOpt @feloxx parser: implement Restore for OnDeleteOpt And OnUpdateOpt parser#98
• ast/ddl.go: ReferenceDef @feloxx implement Restore for ReferenceDef parser#123
• ast/ddl.go: Constraint @feloxx parser: implement Restore for Constraint parser#127
• ast/ddl.go: ColumnOption @feloxx parser: implement Restore for ColumnOption, FieldType and ColumnDef parser#160
• ast/ddl.go: ColumnDef @feloxx parser: implement Restore for ColumnOption, FieldType and ColumnDef parser#160
• ast/ddl.go: ColumnPosition @tony612 parser: implement Restore for ColumnPosition parser#110
• ast/dml.go: Join @exialin parser: implement Restore for TableSource and Join parser#111
• ast/dml.go: DeleteTableList @wangbo parser: implement Restore for DeleteTableList parser#117
• ast/dml.go: TableSource @exialin parser: implement Restore for TableSource and Join parser#111
• ast/dml.go: ByItem @exialin parser: implement Restore for PositionExpr, ByItem and GroupByClause parser#125
• ast/dml.go: GroupByClause @exialin parser: implement Restore for PositionExpr, ByItem and GroupByClause parser#125
• ast/dml.go: HavingClause @SwanSpouse parser: implement Restore for HavingClause parser#129
• ast/dml.go: OrderByClause @SwanSpouse parser: implement Restore for OrderByClause parser#128
• ast/dml.go: OnCondition @exialin parser: implement Restore for OnCondition and TableRefsClause parser#132
• ast/dml.go: TableRefsClause @exialin parser: implement Restore for OnCondition and TableRefsClause parser#132
• ast/dml.go: FrameBound @exialin parser: implement Restore for FrameBound parser#135
• ast/dml.go: Assignment @924060929 parser: implement Restore for Assignment parser#146
• ast/dml.go: WindowSpec @exialin parser: implement Restore for FrameClause, PartitionByClause, WindowSpec and WindowFuncExpr parser#143
• ast/dml.go: PartitionByClause @exialin parser: implement Restore for FrameClause, PartitionByClause, WindowSpec and WindowFuncExpr parser#143
• ast/dml.go: FrameClause @exialin parser: implement Restore for FrameClause, PartitionByClause, WindowSpec and WindowFuncExpr parser#143
• ast/dml.go: UnionSelectList @AndrewDi parser: implement Restore for SelectStmt parser#153

Stage Three:

• ast/ddl.go: CreateDatabaseStmt @leoppro *: support AST to SQL text parser#56
• ast/ddl.go: DropDatabaseStmt @leoppro *: support AST to SQL text parser#56
• ast/ddl.go: DropIndexStmt @honestold3 parser: implement Restore for DropIndexStmt parser#83
• ast/ddl.go: CreateTableStmt @feloxx parser: implement Restore for CreateTableStmt parser#170
• ast/ddl.go: DropTableStmt @caohe parser: implement Restore for DropTableStmt parser#107
• ast/ddl.go: TruncateTableStmt @o-oops parser: implement Restore for TruncateTableStmt parser#122
• ast/ddl.go: RenameTableStmt @liutang123 parser: implement Restore for RenameTableStmt parser#114
• ast/ddl.go: CreateViewStmt @AndrewDi parser: implement Restore for CreateViewStmt parser#139
• ast/ddl.go: CreateIndexStmt @firekillice parser: implement Restore for CreateIndexStmt parser#150
• ast/ddl.go: AlterTableSpec @buzzers parser: implement Restore for AlterTableStmt and AlterTableSpec parser#154
• ast/ddl.go: AlterTableStmt @buzzers parser: implement Restore for AlterTableStmt and AlterTableSpec parser#154

Stage Four:

• ast/dml.go: InsertStmt @exialin parser: implement Restore for InsertStmt parser#168
• ast/dml.go: SelectStmt @AndrewDi parser: implement Restore for SelectStmt parser#153
• ast/dml.go: UnionStmt @AndrewDi parser: implement Restore for SelectStmt parser#153
• ast/dml.go: ShowStmt @GunaYX parser: implement Restore for ShowStmt parser#178
• ast/dml.go: LoadDataStmt @GunaYX parser: implement Restore for LoadDataStmt parser#184
• ast/dml.go: DeleteStmt @arnkore implement Restore for DeleteStmt parser#189
• ast/dml.go: UpdateStmt @arnkore parser: implement restore for UpdateStmt parser#190

Stage Five:

• ast/misc.go: UseStmt @leoppro *: support AST to SQL text parser#56
• ast/stats.go: DropStatsStmt @TennyZhuang parser: implement Restore for DropStatsStmt parser#97
• ast/misc.go: BeginStmt @shinytang6 parser: implement Restore for BeginStmt,CommitStmt,RollbackStmt, AnalyzeTableStmt and LoadStatsStmt parser#144
• ast/misc.go: CommitStmt @shinytang6 parser: implement Restore for BeginStmt,CommitStmt,RollbackStmt, AnalyzeTableStmt and LoadStatsStmt parser#144
• ast/misc.go: RollbackStmt @shinytang6 parser: implement Restore for BeginStmt,CommitStmt,RollbackStmt, AnalyzeTableStmt and LoadStatsStmt parser#144
• ast/stats.go: AnalyzeTableStmt @shinytang6 parser: implement Restore for BeginStmt,CommitStmt,RollbackStmt, AnalyzeTableStmt and LoadStatsStmt parser#144
• ast/stats.go: LoadStatsStmt @shinytang6 parser: implement Restore for BeginStmt,CommitStmt,RollbackStmt, AnalyzeTableStmt and LoadStatsStmt parser#144
• ast/misc.go: TraceStmt @GunaYX parser: implement Restore for TraceStmt parser#167
• ast/misc.go: TableOptimizerHint @AndrewDi parser: implement Restore for SelectStmt parser#153
• ast/misc.go: ExplainStmt @eiantee parser: implement Restore for PrepareStmt ExplainStmt ExecuteStmt Dea… parser#193
• ast/misc.go: PrepareStmt @eiantee parser: implement Restore for PrepareStmt ExplainStmt ExecuteStmt Dea… parser#193
• ast/misc.go: DeallocateStmt @eiantee parser: implement Restore for PrepareStmt ExplainStmt ExecuteStmt Dea… parser#193
• ast/misc.go: ExecuteStmt @eiantee parser: implement Restore for PrepareStmt ExplainStmt ExecuteStmt Dea… parser#193
• ast/misc.go: BinlogStmt @exialin parser: implement Restore for BinlogStmt, FlushStmt, KillStmt, DoStmt and AdminStmt parser#196
• ast/misc.go: VariableAssignment @exialin parser: implement Restore for VariableAssignment, SetStmt and SetPwdStmt parser#199
• ast/misc.go: FlushStmt @exialin parser: implement Restore for BinlogStmt, FlushStmt, KillStmt, DoStmt and AdminStmt parser#196
• ast/misc.go: KillStmt @exialin parser: implement Restore for BinlogStmt, FlushStmt, KillStmt, DoStmt and AdminStmt parser#196
• ast/misc.go: SetStmt @exialin parser: implement Restore for VariableAssignment, SetStmt and SetPwdStmt parser#199
• ast/misc.go: SetPwdStmt @exialin parser: implement Restore for VariableAssignment, SetStmt and SetPwdStmt parser#199
• ast/misc.go: CreateUserStmt @exialin parser: implement Restore for CreateUserStmt, AlterUserStmt and DropUserStmt parser#197
• ast/misc.go: AlterUserStmt @exialin parser: implement Restore for CreateUserStmt, AlterUserStmt and DropUserStmt parser#197
• ast/misc.go: DropUserStmt @exialin parser: implement Restore for CreateUserStmt, AlterUserStmt and DropUserStmt parser#197
• ast/misc.go: DoStmt @exialin parser: implement Restore for BinlogStmt, FlushStmt, KillStmt, DoStmt and AdminStmt parser#196
• ast/misc.go: AdminStmt @exialin parser: implement Restore for BinlogStmt, FlushStmt, KillStmt, DoStmt and AdminStmt parser#196
• ast/misc.go: PrivElem @exialin parser: implement Restore for PrivElem, GrantStmt and RevokeStmt parser#198
• ast/misc.go: RevokeStmt @exialin parser: implement Restore for PrivElem, GrantStmt and RevokeStmt parser#198
• ast/misc.go: GrantStmt @exialin parser: implement Restore for PrivElem, GrantStmt and RevokeStmt parser#198

[AndrewDi]

Waiting this feature to rewriter view's sql...I think we could use create view func to test this feature later.

[zier-one]

Many thanks for your contributions.
All the tasks have been completed.