Add ALTER EXTERNAL LANGUAGE statement parsing

- Add AUTHORIZATION clause support
- Add SET/ADD/REMOVE operation parsing
- Add file options (CONTENT, FILE_NAME, PLATFORM, PARAMETERS, ENVIRONMENT_VARIABLES)
- Add REMOVE PLATFORM option
- Update AlterExternalLanguageStatement AST type
- Enable AlterExternalLanguage150 and Baselines150_AlterExternalLanguage150 tests

Author: claude

ast/external_statements.go

@@ -133,6 +133,9 @@ func (s *AlterExternalDataSourceStatement) statement() {}
 // AlterExternalLanguageStatement represents ALTER EXTERNAL LANGUAGE statement
 type AlterExternalLanguageStatement struct {
 	Name                  *Identifier
+	Owner                 *Identifier
+	Operation             *Identifier
+	Platform              *Identifier
 	ExternalLanguageFiles []*ExternalLanguageFileOption
 }
 

parser/marshal.go

@@ -14650,9 +14650,25 @@ func alterExternalLanguageStatementToJSON(s *ast.AlterExternalLanguageStatement)
 	node := jsonNode{
 		"$type": "AlterExternalLanguageStatement",
 	}
+	if s.Platform != nil {
+		node["Platform"] = identifierToJSON(s.Platform)
+	}
+	if s.Operation != nil {
+		node["Operation"] = identifierToJSON(s.Operation)
+	}
+	if s.Owner != nil {
+		node["Owner"] = identifierToJSON(s.Owner)
+	}
 	if s.Name != nil {
 		node["Name"] = identifierToJSON(s.Name)
 	}
+	if len(s.ExternalLanguageFiles) > 0 {
+		files := make([]jsonNode, len(s.ExternalLanguageFiles))
+		for i, f := range s.ExternalLanguageFiles {
+			files[i] = externalLanguageFileOptionToJSON(f)
+		}
+		node["ExternalLanguageFiles"] = files
+	}
 	return node
 }
 

parser/parse_ddl.go

@@ -6330,8 +6330,83 @@ func (p *Parser) parseAlterExternalLanguageStatement() (*ast.AlterExternalLangua
 	// Parse name
 	stmt.Name = p.parseIdentifier()
 
-	// Skip rest of statement
-	p.skipToEndOfStatement()
+	// Parse optional AUTHORIZATION
+	if strings.ToUpper(p.curTok.Literal) == "AUTHORIZATION" {
+		p.nextToken() // consume AUTHORIZATION
+		stmt.Owner = p.parseIdentifier()
+	}
+
+	// Parse operation (SET, ADD, REMOVE)
+	upperLit := strings.ToUpper(p.curTok.Literal)
+	if upperLit == "SET" || upperLit == "ADD" || upperLit == "REMOVE" {
+		stmt.Operation = p.parseIdentifier()
+
+		if upperLit == "REMOVE" {
+			// REMOVE PLATFORM <platform>
+			if strings.ToUpper(p.curTok.Literal) == "PLATFORM" {
+				p.nextToken() // consume PLATFORM
+				stmt.Platform = p.parseIdentifier()
+			}
+		} else {
+			// SET or ADD - parse file options
+			if p.curTok.Type == TokenLParen {
+				p.nextToken() // consume (
+				fileOption := &ast.ExternalLanguageFileOption{}
+				for p.curTok.Type != TokenRParen && p.curTok.Type != TokenEOF {
+					switch strings.ToUpper(p.curTok.Literal) {
+					case "CONTENT":
+						p.nextToken() // consume CONTENT
+						if p.curTok.Type == TokenEquals {
+							p.nextToken() // consume =
+						}
+						expr, _ := p.parseScalarExpression()
+						fileOption.Content = expr
+					case "FILE_NAME":
+						p.nextToken() // consume FILE_NAME
+						if p.curTok.Type == TokenEquals {
+							p.nextToken() // consume =
+						}
+						expr, _ := p.parseScalarExpression()
+						fileOption.FileName = expr
+					case "PLATFORM":
+						p.nextToken() // consume PLATFORM
+						if p.curTok.Type == TokenEquals {
+							p.nextToken() // consume =
+						}
+						fileOption.Platform = p.parseIdentifier()
+					case "PARAMETERS":
+						p.nextToken() // consume PARAMETERS
+						if p.curTok.Type == TokenEquals {
+							p.nextToken() // consume =
+						}
+						expr, _ := p.parseScalarExpression()
+						fileOption.Parameters = expr
+					case "ENVIRONMENT_VARIABLES":
+						p.nextToken() // consume ENVIRONMENT_VARIABLES
+						if p.curTok.Type == TokenEquals {
+							p.nextToken() // consume =
+						}
+						expr, _ := p.parseScalarExpression()
+						fileOption.EnvironmentVariables = expr
+					default:
+						p.nextToken()
+					}
+					if p.curTok.Type == TokenComma {
+						p.nextToken()
+					}
+				}
+				if p.curTok.Type == TokenRParen {
+					p.nextToken() // consume )
+				}
+				stmt.ExternalLanguageFiles = append(stmt.ExternalLanguageFiles, fileOption)
+			}
+		}
+	}
+
+	// Skip optional semicolon
+	if p.curTok.Type == TokenSemicolon {
+		p.nextToken()
+	}
 
 	return stmt, nil
 }

parser/testdata/AlterExternalLanguage150/metadata.json

@@ -1 +1 @@
-{"todo": true}
+{}

parser/testdata/Baselines150_AlterExternalLanguage150/metadata.json

@@ -1 +1 @@
-{"todo": true}
+{}