1. Custom Function Basic Syntax (Consistent with General Programming Language Syntax)

Example: <data_type> <variable> = <expression>

Syntax Component	Description
Data Type	12 major data types are provided in custom functions (case-sensitive). Refer to Data Types chapter for details
Variable	Name of the data for subsequent logic calls (cannot be the same as data type names)
Expression	The value assigned to the variable, which can be directly defined or an expression (ensure return type matches data type to avoid errors)

Note: In custom functions, 'def' can be used to represent data type, which will be automatically recognized during compilation

Examples:

    String str = "fxiaoke" //direct definition

    Boolean boo = ["red", "blue", "green", "yellow"].isEmpty() //expression definition

    def result = ["red", "blue", "green", "yellow"].isEmpty() //using def for data type

2. switch

Used to evaluate given conditions and execute corresponding operations based on the evaluation result (true/false)

2.1 Definition

        switch(<key>){
           case <value-1>: statements-1; break;
           case <value-2>: statements-2; break;
           default: statements-3; break;
       }
       
       //Execution order: When key equals value-1, execute statements-1 and exit; 
       //if key doesn't equal value-1 but equals value-2, execute statements-2 and exit;
       //...; if no matches found, execute statements-3 and exit

Notes:

1. Multiple case statements can exist
2. default statement is optional but recommended (maximum one) to prevent errors from unmatched cases
3. break statement can be omitted after each case/default, which means continuing execution (e.g. without break, when key equals value-2, it would execute both statements-2 and statements-3)

2.2 Example

        Integer day = 3
        switch (day) {
            case 0:   x="Today it's Sunday";    break;
            case 1:   x="Today it's Monday";    break;
            case 2:   x="Today it's Tuesday";   break;
            case 3:   x="Today it's Wednesday"; break;
            case 4:   x="Today it's Thursday";  break;
            case 5:   x="Today it's Friday";    break;
            case 6:   x="Today it's Saturday";  break;
       }//Final result: Today it's Wednesday

3. if-else

Used to evaluate given conditions and execute corresponding operations based on the evaluation result (true/false)

3.1 Definition

        if(condition1) {
           Execute this if condition1 is true
       }else if(condition2){
           Execute this if condition2 is true
       }else {
           Execute this if neither condition1 nor condition2 is true
       }

Note: if-else control statements must include both if and else, while else if can have zero or multiple instances depending on requirements

3.2 Example

        String str = "fxiaoke"
       if(str.contains("s")) {
           str = "hello"
       }else if(str.contains("f")){
           str = "welcome"
       }else {
           str = "hi"
       }//Final result: str=welcome