ast: Add support for CREATE TYPE as ENUM (#388)

MySQL and SQLite do not support CREATE TYPE ... ENUM, so this change
mainly involves porting the existing enum support from the dinosql /
catalog package to the sql/catalog package

Author: kyleconroy

internal/compiler/compile.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -23,6 +24,35 @@ type Parser interface {
 	Parse(io.Reader) ([]ast.Statement, error)
 }
 
+// copied over from gen.go
+func structName(name string) string {
+	out := ""
+	for _, p := range strings.Split(name, "_") {
+		if p == "id" {
+			out += "ID"
+		} else {
+			out += strings.Title(p)
+		}
+	}
+	return out
+}
+
+var identPattern = regexp.MustCompile("[^a-zA-Z0-9_]+")
+
+func enumValueName(value string) string {
+	name := ""
+	id := strings.Replace(value, "-", "_", -1)
+	id = strings.Replace(id, ":", "_", -1)
+	id = strings.Replace(id, "/", "_", -1)
+	id = identPattern.ReplaceAllString(id, "")
+	for _, part := range strings.Split(id, "_") {
+		name += strings.Title(part)
+	}
+	return name
+}
+
+// end copypasta
+
 func Run(conf config.SQL, combo config.CombinedSettings) (*Result, error) {
 	var p Parser
 
@@ -53,25 +83,52 @@ func Run(conf config.SQL, combo config.CombinedSettings) (*Result, error) {
 	}
 
 	var structs []dinosql.GoStruct
+	var enums []dinosql.GoEnum
 	for _, schema := range c.Schemas {
 		for _, table := range schema.Tables {
 			s := dinosql.GoStruct{
-				Table: pg.FQN{Schema: table.Rel.Schema, Rel: table.Rel.Name},
+				Table: pg.FQN{Schema: schema.Name, Rel: table.Rel.Name},
 				Name:  strings.Title(table.Rel.Name),
 			}
 			for _, col := range table.Columns {
 				s.Fields = append(s.Fields, dinosql.GoField{
-					Name: strings.Title(col.Name),
+					Name: structName(col.Name),
 					Type: "string",
 					Tags: map[string]string{"json:": col.Name},
 				})
 			}
 			structs = append(structs, s)
 		}
+		for _, typ := range schema.Types {
+			switch t := typ.(type) {
+			case catalog.Enum:
+				var name string
+				// TODO: This name should be public, not main
+				if schema.Name == "main" {
+					name = t.Name
+				} else {
+					name = schema.Name + "_" + t.Name
+				}
+				e := dinosql.GoEnum{
+					Name: structName(name),
+				}
+				for _, v := range t.Vals {
+					e.Constants = append(e.Constants, dinosql.GoConstant{
+						Name:  e.Name + enumValueName(v),
+						Value: v,
+						Type:  e.Name,
+					})
+				}
+				enums = append(enums, e)
+			}
+		}
 	}
+
 	if len(structs) > 0 {
 		sort.Slice(structs, func(i, j int) bool { return structs[i].Name < structs[j].Name })
 	}
-
-	return &Result{structs: structs}, nil
+	if len(enums) > 0 {
+		sort.Slice(enums, func(i, j int) bool { return enums[i].Name < enums[j].Name })
+	}
+	return &Result{structs: structs, enums: enums}, nil
 }

internal/compiler/result.go

@@ -6,6 +6,7 @@ import (
 )
 
 type Result struct {
+	enums   []dinosql.GoEnum
 	structs []dinosql.GoStruct
 	queries []dinosql.GoQuery
 }
@@ -19,5 +20,5 @@ func (r *Result) GoQueries(settings config.CombinedSettings) []dinosql.GoQuery {
 }
 
 func (r *Result) Enums(settings config.CombinedSettings) []dinosql.GoEnum {
-	return nil
+	return r.enums
 }

internal/endtoend/testdata/experimental_elephant/go/models.go

@@ -6,6 +6,8 @@ CREATE TABLE bar (
         baz text NOT NULL 
 );
 
+CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
+
 SELECT bar FROM foo;
 
 DROP TABLE bar;

internal/endtoend/testdata/experimental_elephant/query.sql

@@ -22,6 +22,30 @@ func stringSlice(list nodes.List) []string {
 	return items
 }
 
+func parseTypeName(node nodes.Node) (*ast.TypeName, error) {
+	switch n := node.(type) {
+
+	case nodes.List:
+		parts := stringSlice(n)
+		switch len(parts) {
+		case 1:
+			return &ast.TypeName{
+				Name: parts[0],
+			}, nil
+		case 2:
+			return &ast.TypeName{
+				Schema: parts[0],
+				Name:   parts[1],
+			}, nil
+		default:
+			return nil, fmt.Errorf("invalid type name: %s", join(n, "."))
+		}
+
+	default:
+		return nil, fmt.Errorf("unexpected node type: %T", n)
+	}
+}
+
 func parseTableName(node nodes.Node) (*ast.TableName, error) {
 	switch n := node.(type) {
 
@@ -180,6 +204,25 @@ func translate(node nodes.Node) (ast.Node, error) {
 		}
 		return create, nil
 
+	case nodes.CreateEnumStmt:
+		name, err := parseTypeName(n.TypeName)
+		if err != nil {
+			return nil, err
+		}
+		stmt := &ast.CreateEnumStmt{
+			TypeName: name,
+			Vals:     &ast.List{},
+		}
+		for _, val := range n.Vals.Items {
+			switch v := val.(type) {
+			case nodes.String:
+				stmt.Vals.Items = append(stmt.Vals.Items, &ast.String{
+					Str: v.Str,
+				})
+			}
+		}
+		return stmt, nil
+
 	case nodes.DropStmt:
 		drop := &ast.DropTableStmt{
 			IfExists: n.MissingOk,

internal/postgresql/parse.go

@@ -57,6 +57,15 @@ func (n *AlterTableCmd) Pos() int {
 	return 0
 }
 
+type CreateEnumStmt struct {
+	TypeName *TypeName
+	Vals     *List
+}
+
+func (n *CreateEnumStmt) Pos() int {
+	return 0
+}
+
 type CreateTableStmt struct {
 	IfNotExists bool
 	Name        *TableName
@@ -88,7 +97,8 @@ func (n *ColumnDef) Pos() int {
 }
 
 type TypeName struct {
-	Name string
+	Schema string
+	Name   string
 }
 
 func (n *TypeName) Pos() int {
@@ -127,3 +137,11 @@ type ColumnRef struct {
 func (n *ColumnRef) Pos() int {
 	return 0
 }
+
+type String struct {
+	Str string
+}
+
+func (n *String) Pos() int {
+	return 0
+}

internal/sql/ast/ast.go

@@ -21,6 +21,8 @@ func Build(stmts []ast.Statement) (*Catalog, error) {
 		switch n := stmts[i].Raw.Stmt.(type) {
 		case *ast.AlterTableStmt:
 			err = c.alterTable(n)
+		case *ast.CreateEnumStmt:
+			err = c.createEnum(n)
 		case *ast.CreateTableStmt:
 			err = c.createTable(n)
 		case *ast.DropTableStmt:
@@ -33,8 +35,19 @@ func Build(stmts []ast.Statement) (*Catalog, error) {
 	return c, nil
 }
 
+func stringSlice(list *ast.List) []string {
+	items := []string{}
+	for _, item := range list.Items {
+		if n, ok := item.(*ast.String); ok {
+			items = append(items, n.Str)
+		}
+	}
+	return items
+}
+
 // TODO: This need to be rich error types
 var ErrRelationNotFound = errors.New("relation not found")
+var ErrRelationAlreadyExists = errors.New("relation already exists")
 var ErrSchemaNotFound = errors.New("schema not found")
 var ErrColumnNotFound = errors.New("column not found")
 var ErrColumnExists = errors.New("column already exists")
@@ -159,6 +172,37 @@ func (c *Catalog) alterTable(stmt *ast.AlterTableStmt) error {
 	return nil
 }
 
+func (c *Catalog) createEnum(stmt *ast.CreateEnumStmt) error {
+	ns := stmt.TypeName.Schema
+	if ns == "" {
+		ns = c.DefaultSchema
+	}
+	schema, err := c.getSchema(ns)
+	if err != nil {
+		return err
+	}
+	// Because tables have associated data types, the type name must also
+	// be distinct from the name of any existing table in the same
+	// schema.
+	// https://www.postgresql.org/docs/current/sql-createtype.html
+	tbl := &ast.TableName{
+		Name: stmt.TypeName.Name,
+	}
+	if _, _, err := schema.getTable(tbl); err == nil {
+		// return wrap(pg.ErrorRelationAlreadyExists(fqn.Rel), raw.StmtLocation)
+		return ErrRelationAlreadyExists
+	}
+	if _, err := schema.getType(stmt.TypeName); err == nil {
+		// return wrap(pg.ErrorTypeAlreadyExists(fqn.Rel), raw.StmtLocation)
+		return ErrRelationAlreadyExists
+	}
+	schema.Types = append(schema.Types, Enum{
+		Name: stmt.TypeName.Name,
+		Vals: stringSlice(stmt.Vals),
+	})
+	return nil
+}
+
 func (c *Catalog) createTable(stmt *ast.CreateTableStmt) error {
 	ns := stmt.Name.Schema
 	if ns == "" {
@@ -223,9 +267,22 @@ type Catalog struct {
 type Schema struct {
 	Name    string
 	Tables  []*Table
+	Types   []Type
 	Comment string
 }
 
+func (s *Schema) getType(rel *ast.TypeName) (Type, error) {
+	for i := range s.Types {
+		switch typ := s.Types[i].(type) {
+		case Enum:
+			if typ.Name == rel.Name {
+				return s.Types[i], nil
+			}
+		}
+	}
+	return nil, ErrRelationNotFound
+}
+
 func (s *Schema) getTable(rel *ast.TableName) (*Table, int, error) {
 	for i := range s.Tables {
 		if s.Tables[i].Rel.Name == rel.Name {
@@ -247,3 +304,16 @@ type Column struct {
 	Type      ast.TypeName
 	IsNotNull bool
 }
+
+type Type interface {
+	isType()
+}
+
+type Enum struct {
+	Name    string
+	Vals    []string
+	Comment string
+}
+
+func (e Enum) isType() {
+}