Chapter 20
Expressions
Describes the purpose and syntax of each G2 expression.
- Introduction
- Forming an Expression
- Evaluating Expressions
- Never Obtaining a Value
- Not Obtaining a Value at This Time
- Finding a Type Mismatch
- Determining When Expressions Expire
- Understanding Transactions and Transaction Scopes
- Using Generic Reference Expressions
- Including a Generic Reference Qualifier Expression
- Using Quantifiers
- Embedded Generic Reference Expressions
- Using Class-Qualified Names
- Using Local Names in Expressions
- Implicit Use
- Explicit Use
- Class or Attribute Name Use
- Using Literals
- Using Operators in Expressions
- Using Arithmetic Operators
- Identifying the Default Order of Evaluation
- Using Parentheses to Affect the Order of Evaluation
- Precedence of Arithmetic Operators
- Coercion of Values Returned from Arithmetic Operators
- Constraints on Exponentiation Operations
- Using Logical Operators
- Short-Circuited (Lazy) Evaluation of Logical Operators
- Affecting the Expiration Time
- Precedence and Order of Evaluation
- Using Relational Operators
- Producing Fuzzy Truth Values From Relational Operations
- Specifying a Fuzzy Truth Band Subexpression
- Using Logical Operators with Terms That Produce Fuzzy Truth Values
- Fuzzy Truth Operators
- Using the Concatenation Operator
- Formatting Using the Newline Character
- Formatting Numeric Values
- Producing a Symbol Value
- Referring to a Superior or Inferior Class
- Referring to Items or Values
- Existence of an Item or Value
- There Exists
- Class or Type of Item or Value
- By Generic Reference
- Conditional Evaluation
- Value Expressions
- Value of an Item or Value
- Has a Value
- First of the Following Expressions That Has a Value
- Current Value of an Expression
- Current Value of
- Has a Current Value
- First of the Following Expressions That Has a Current Value
- By Iterating Over a Set
- The Count of
- The Average Over Each
- Other Operations Over a Set
- Referring to the Current Time
- Current Subsecond Time
- Current Time by Time Unit
- Current Day of the Week
- Referring to Specific Items
Copyright © 1997 Gensym Corporation, Inc.