Lexical Structure

This page describes the tokens that make up the MDL language: keywords, literals, and identifiers.

Keywords

MDL keywords are case-insensitive. The following are reserved keywords:

ACCESS, ACTIONS, ADD, AFTER, ALL, ALTER, AND, ANNOTATION, AS, ASC,
ASCENDING, ASSOCIATION, AUTONUMBER, BATCH, BEFORE, BEGIN, BINARY,
BOOLEAN, BOTH, BUSINESS, BY, CALL, CANCEL, CAPTION, CASCADE,
CATALOG, CHANGE, CHILD, CLOSE, COLUMN, COMBOBOX, COMMIT, CONNECT,
CONFIGURATION, CONNECTOR, CONSTANT, CONSTRAINT, CONTAINER, CREATE,
CRUD, DATAGRID, DATAVIEW, DATE, DATETIME, DECLARE, DEFAULT, DELETE,
DELETE_BEHAVIOR, DELETE_BUT_KEEP_REFERENCES, DELETE_AND_REFERENCES, DEMO,
DEPTH, DESC, DESCENDING, DESCRIBE, DIFF, DISCONNECT, DROP, ELSE,
EMPTY, END, ENTITY, ENUMERATION, ERROR, EVENT, EVENTS, EXECUTE,
EXEC, EXIT, EXPORT, EXTENDS, EXTERNAL, FALSE, FOLDER, FOOTER,
FOR, FORMAT, FROM, FULL, GALLERY, GENERATE, GRANT, HEADER, HELP,
HOME, IF, IMPORT, IN, INDEX, INFO, INSERT, INTEGER, INTO, JAVA,
KEEP_REFERENCES, LABEL, LANGUAGE, LAYOUT, LAYOUTGRID, LEVEL, LIMIT,
LINK, LIST, LISTVIEW, LOCAL, LOG, LOGIN, LONG, LOOP, MANAGE, MAP,
MATRIX, MENU, MESSAGE, MICROFLOW, MICROFLOWS, MODEL, MODIFY, MODULE,
MODULES, MOVE, NANOFLOW, NANOFLOWS, NAVIGATION, NODE, NON_PERSISTENT,
NOT, NULL, OF, ON, OR, ORACLE, OVERVIEW, OWNER, PAGE, PAGES, PARENT,
PASSWORD, PERSISTENT, POSITION, POSTGRES, PRODUCTION, PROJECT,
PROTOTYPE, QUERY, QUIT, REFERENCE, REFERENCESET, REFRESH, REMOVE,
REPLACE, REPORT, RESPONSIVE, RETRIEVE, RETURN, REVOKE, ROLE, ROLES,
ROLLBACK, ROW, SAVE, SCRIPT, SEARCH, SECURITY, SELECTION, SET, SHOW,
SNIPPET, SNIPPETS, SQL, SQLSERVER, STATUS, STRING, STRUCTURE,
TABLES, TEXTBOX, TEXTAREA, THEN, TO, TRUE, TYPE, UNIQUE, UPDATE,
USER, VALIDATION, VALUE, VIEW, VIEWS, VISIBLE, WARNING, WHERE, WIDGET,
WIDGETS, WITH, WORKFLOWS, WRITE

Most keywords work unquoted as identifiers (entity names, attribute names). Only structural keywords like CREATE, DELETE, BEGIN, END, RETURN, ENTITY, and MODULE require quoting when used as identifiers.

Quoting escapes parser keywords only — not platform-reserved member names. Quoting an identifier tells the MDL parser to treat it as a name rather than a token, so "create", "status", and "type" parse fine as attribute names. But some names are reserved by the Mendix platform, and Studio Pro rejects them even when quoted (the quotes are stripped, and the bare name is still invalid): Type (CE7247), the audit attributes CreatedDate / ChangedDate / Owner / ChangedBy, plus ID, GUID, CurrentUser, and the Java keyword list. mxcli check --references flags these as MDL021 (CE7247) / MDL020. Rename them (e.g. Type → ResourceType); use the AutoCreatedDate / AutoChangedDate / AutoOwner / AutoChangedBy pseudo-types for the audit fields.

Literals

String Literals

String literals use single quotes:

'single quoted string'
'it''s here'            -- doubled single quote to escape

The only escape sequence is '' (two single quotes) to represent a literal single quote. Backslash escaping is not supported.

Numeric Literals

42          -- Integer
3.14        -- Decimal
-100        -- Negative integer
1.5e10      -- Scientific notation

Boolean Literals

TRUE
FALSE

Quoted Identifiers

When an identifier collides with a reserved keyword, use double quotes (ANSI SQL style) or backticks (MySQL style):

"ComboBox"."CategoryTreeVE"
`Order`.`Status`
"ComboBox".CategoryTreeVE    -- mixed quoting is allowed

See Qualified Names for more on identifier syntax and the Module.Name notation.