Expressions Syntax [AX 2012]
Updated: February 1, 2012
Applies To: Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012
An expression in X++ is used in either a mathematical or logical way. Expressions are built on the data types of the language; that is, an expression returns a value of some type. This value can be used in calculations, assignments, conditional statements, and so on.
| Expression | = | Simple-expression [RelationalOperator Simple-expression ] |
| RelationalOperator | = | = | != | < | > | <= | >= | like |
| Simple-expression | = | Simple-expression [ + | - | | ] Term | Term |
| Term | = | Compfactor { Mult-operator CompFactor } |
| Mult-operator | = | * | / | div | mod | << | >> | & | ^ | | |
| CompFactor | = | [ ! ] [ - | ~ ] Factor |
| Factor | = | Literal | Enum | Variable | FunctionCall | ( If-expression ) | Select-expression |
| Enum | = | EnumName :: Literal |
| Variable | = | Identifier [ [ Expression ] ] [ . Expression ] |
| FunctionCall | = | [ Expression (. | ::) | this . ] FunctionName ( argumentlist ) |
| If-expression | = | Expression ? Expression : Expression |
Semantic restrictions apply on the preceding syntax. You cannot call any method using the :: operator. Similarly, you cannot use the this keyword without an active object; that is, if you are not within a method and so on.
| Example of expression | Description |
|---|---|
| 1 | An integer literal. |
| NoYes::No | An enum-reference. |
| A | A variable-reference. |
| Debtor::Find("1") | A static method-call (returns a customer variable). |
| (A > 3 ? true : false) | An if-expression that returns true or false. |
| (select CustTable where CustTable.Account == "100").NameRef | A select-expression. Returns the nameref field in the customer table. This is a string. |
| A >= B | A logical expression. Returns true or false. |
| A + B | An arithmetic expression. Sums A and B. |
| A + B / C | Calculates B/C, and then adds this to A. |
| ~A + this.Value() | Sums binary not A and the result of the method-call Value on the object in scope (this). |
| Debtor::Find("1").NameRef | Returns the NameRef field of the found customer record. |
| Debtor::Find("1").Balance() | A method call to Balance in the customer table (Debtor::Find returns a customer). Returns the balance of the customer with account number 1. |
