### Join Function Usage Examples

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/JoinFunction.html

Demonstrates how to use the $join function to concatenate strings from an array. The first example shows joining without a separator, and the second shows joining with a specified separator after a split operation.

```jsonata
$join(['a','b','c'])=="abc"
```

```jsonata
$split("too much, punctuation. hard; to read", /[" ",".",";"]+/, 3) ~> $join(', ')=="too, much, punctuation"
```

--------------------------------

### PadFunction Examples

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/PadFunction.html

Demonstrates various use cases of the $pad function, including right padding, left padding, and padding with a custom character. Also shows integration with $formatBase.

```jsonata
$pad("foo", 5)=="foo "
```

```jsonata
$pad("foo", -5)==" foo"
```

```jsonata
$pad("foo", -5, "#") == "##foo"
```

```jsonata
$formatBase(35, 2) ~> $pad(-8, '0')=="00100011"
```

--------------------------------

### Build JSONata4Java JARs with Maven

Source: https://github.com/ibm/jsonata4java/blob/master/README.md

Use Maven to clean and install the project, generating the necessary JAR files in the target directory. Ensure project dependencies are updated first.

```bash
mvn clean install -Dgpg.skip
```

--------------------------------

### Maven Build Configuration

Source: https://github.com/ibm/jsonata4java/blob/master/.README.md.html

Instructions for building the project using Maven. Ensure dependencies are updated before running a clean install.

```xml
<dependency>
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
       <version>2.9.8</version>
    </dependency>
```

--------------------------------

### Build and Deploy JSONata4Java JARs to Maven Central

Source: https://github.com/ibm/jsonata4java/blob/master/README.md

Execute this command to build, install, and deploy the JARs to Maven Central. This requires release profile activation.

```bash
mvn clean install deploy -Prelease
```

--------------------------------

### JSON Data for Customer Mapping

Source: https://github.com/ibm/jsonata4java/blob/master/README.md

Example JSON data structure used for demonstrating function chaining with customer names.

```json
{
  "Customer": [
    "    paul   ",
    "  berverly     "
  ]
}
```

--------------------------------

### NowFunction

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/package-tree.html

Gets the current date and time.

```APIDOC
## NowFunction

### Description
Returns the current date and time in ISO 8601 format.

### Method
Function Call

### Request Example
```jsonata
NowFunction()
```

### Response
#### Success Response
- **dateTime** (string) - The current date and time in ISO 8601 format.
```

--------------------------------

### JSONata $random() Function Examples (Test)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-17.html

Illustrates the $random() function within a testing context, showing expected outputs for pseudo-random number generation.

```jsonata
$random()==0.7973541067127
```

```jsonata
$random()==0.4029142127028
```

```jsonata
$random()==0.6558078550072
```

--------------------------------

### Demonstrate JSONata4Java Date/Time Functions in Java

Source: https://context7.com/ibm/jsonata4java/llms.txt

This Java example illustrates the use of JSONata built-in date and time functions, including $millis, $fromMillis, $toMillis, $fromMillisZoned, and $now, for handling epoch milliseconds and ISO-8601 date strings.

```java
import com.api.jsonata4java.expressions.Expressions;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;

public class DateTimeFunctionsExample {
    public static void main(String[] args) throws Exception {
        JsonNode nil = JsonNodeFactory.instance.objectNode();

        // $millis — current epoch ms (varies at runtime)
        JsonNode ms = Expressions.parse("$millis()").evaluate(nil);
        System.out.println(ms); // e.g. 1718000000000

        // $fromMillis — epoch ms → ISO-8601 string
        JsonNode iso = Expressions.parse("$fromMillis(1510067557121)").evaluate(nil);
        System.out.println(iso); // "2017-11-07T15:12:37.121Z"

        // $toMillis — ISO-8601 string → epoch ms
        JsonNode epoch = Expressions.parse("$toMillis(\"2017-11-07T15:12:37.121Z\")").evaluate(nil);
        System.out.println(epoch); // 1510067557121

        // $fromMillisZoned — with timezone (v2.4+)
        JsonNode localTime = Expressions.parse(
            "$fromMillisZoned(1510067557121, \"[Y]-[M01]-[D01]T[H01]:[m01]:[s01]\", \"America/New_York\")"
        ).evaluate(nil);
        System.out.println(localTime); // "2017-11-07T10:12:37"

        // $now — current ISO-8601 timestamp
        JsonNode now = Expressions.parse("$now()").evaluate(nil);
        System.out.println(now); // e.g. "2024-06-10T12:00:00.000Z"
    }
}
```

--------------------------------

### FormatNumberFunction Examples

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/FormatNumberFunction.html

Demonstrates various ways to format numbers using the $formatNumber function with different picture strings and options. This function is consistent with XPath/XQuery's fn:format-number.

```jsonata
$formatNumber(12345.6, '#,###.00')=="12,345.60"
```

```jsonata
$formatNumber(1234.5678, "00.000e0")=="12.346e2"
```

```jsonata
$formatNumber(34.555, "#0.00;(#0.00)")=="34.56"
```

```jsonata
$formatNumber(-34.555, "#0.00;(#0.00)")=="(34.56)"
```

```jsonata
$formatNumber(0.14, "01%")=="14%"
```

```jsonata
$formatNumber(0.14, "###pm", {"per-mille": "pm"})=="140pm"
```

```jsonata
$formatNumber(1234.5678, "①①.①①①e①", {"zero-digit": "⑟"})=="①②.③④⑥e②"
```

--------------------------------

### ExprOrSeqListContext Constructors and Methods

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ExprOrSeqListContext.html

Details on the constructors and methods available for the ExprOrSeqListContext.

```APIDOC
## Class MappingExpressionParser.ExprOrSeqListContext

### Description
Represents a context in the parser for an expression or sequence list.

### Constructor Summary

*   **ExprOrSeqListContext**(org.antlr.v4.runtime.ParserRuleContext parent, int invokingState)
    *   Constructs a new ExprOrSeqListContext with the specified parent context and invoking state.

### Method Summary

*   **accept**<T>(org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T> visitor) : T
    *   Accepts a visitor for the parse tree.
*   **enterRule**(org.antlr.v4.runtime.tree.ParseTreeListener listener) : void
    *   Enters the rule context for this parser rule.
*   **exitRule**(org.antlr.v4.runtime.tree.ParseTreeListener listener) : void
    *   Exits the rule context for this parser rule.
*   **getExprOrSeqs**() : java.util.List<MappingExpressionParser.ExprOrSeqContext>
    *   Returns a list of all ExprOrSeq contexts within this list.
```

--------------------------------

### main Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/Sequence.html

Entry point for the Sequence class, used for testing or execution.

```APIDOC
## main(String[] args)

### Description

Entry point for the Sequence class, used for testing or execution.

### Method

`main`

### Parameters

#### Path Parameters

- **args** (java.lang.String[]) - Command line arguments.
```

--------------------------------

### MillisFunction

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/package-tree.html

Gets the current time in milliseconds.

```APIDOC
## MillisFunction

### Description
Returns the current time as the number of milliseconds since the Unix epoch.

### Method
Function Call

### Request Example
```jsonata
MillisFunction()
```

### Response
#### Success Response
- **milliseconds** (number) - The current time in milliseconds.
```

--------------------------------

### PathExpressionVisitor.main

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/path/PathExpressionVisitor.html

Entry point for the PathExpressionVisitor class, used for command-line execution.

```APIDOC
## main

### Description
Entry point for the PathExpressionVisitor class.

### Method
public static void main(java.lang.String[] args)

### Parameters
#### Path Parameters
- **args** (java.lang.String[]) - command line arguments
```

--------------------------------

### getRuleIndex() Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ExprListContext.html

Gets the rule index for this context.

```APIDOC
## getRuleIndex()

### Description
Returns the rule index for this parser rule context.

### Overrides
* `getRuleIndex` in class `org.antlr.v4.runtime.RuleContext`

### Returns
* int - The rule index.
```

--------------------------------

### NowFunction.invoke

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/class-use/ExpressionsVisitor.html

Invokes the NowFunction to get the current timestamp.

```APIDOC
## NowFunction.invoke

### Description
Invokes the NowFunction, which returns the current date and time.

### Method Signature
`NowFunction.invoke(ExpressionsVisitor expressionVisitor, MappingExpressionParser.Function_callContext ctx)`

### Parameters
* `expressionVisitor` (ExpressionsVisitor) - The visitor pattern implementation for traversing the expression tree.
* `ctx` (MappingExpressionParser.Function_callContext) - The context of the function call being evaluated.

### Returns
`com.fasterxml.jackson.databind.JsonNode` - A JSON node representing the current timestamp.
```

--------------------------------

### LogorContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.LogorContext.html

Initializes a new instance of the LogorContext class.

```APIDOC
## LogorContext Constructor

### Description
Initializes a new instance of the LogorContext class.

### Parameters
*   **ctx** (MappingExpressionParser.ExprContext) - The expression context to copy from.
```

--------------------------------

### get(JsonNode, Integer)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-7.html

Retrieves an element from a JsonNode at a specified index.

```APIDOC
## get(JsonNode, Integer)

### Description
Retrieves an element from a JsonNode at a specified index.

### Method
Method

### Class
com.api.jsonata4java.expressions.path.PathExpression
```

--------------------------------

### getValuesListExpressionOrNullNode

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/class-use/ExpressionsVisitor.html

Gets the expression at the specified index from the context's ExprValuesContext.

```APIDOC
## getValuesListExpressionOrNullNode

### Description
Gets the expression at the supplied index from the context's {link ExprValuesContext} {link ExprListContext].

### Method Signature
`static com.fasterxml.jackson.databind.JsonNode getValuesListExpressionOrNullNode(ExpressionsVisitor exprVisitor, MappingExpressionParser.Function_callContext ctx, int index)`
```

--------------------------------

### prompt (String)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/JSONataUtils.html

Prints a prompt and returns the trimmed user response.

```APIDOC
## prompt (String)

### Description
Print the supplied prompt (if not null) and return the trimmed response.

### Method Signature
`static java.lang.String prompt(java.lang.String strPrompt)`
```

--------------------------------

### SubstringFunction

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/package-tree.html

Extracts a portion of a string based on start index and length.

```APIDOC
## SubstringFunction

### Description
Extracts a substring from a given string based on a starting position and an optional length.

### Method
N/A (This is a Java class)

### Parameters
- **input** (string): The string to extract from.
- **start** (integer): The starting index (0-based).
- **length** (integer, optional): The number of characters to extract. If omitted, extracts to the end of the string.

### Request Example
N/A

### Response
- **output** (string): The extracted substring.
```

--------------------------------

### MappingExpressionParser.ExprOrSeqContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-5.html

Details the constructor for the `ExprOrSeqContext` class.

```APIDOC
## POST /api/jsonata4java/expressions/generated/MappingExpressionParser/ExprOrSeqContext

### Description
Constructs a new `ExprOrSeqContext` instance.

### Method
POST

### Endpoint
/api/jsonata4java/expressions/generated/MappingExpressionParser/ExprOrSeqContext

### Parameters
#### Request Body
- **parserRuleContext** (org.antlr.v4.runtime.ParserRuleContext) - Required - The parent parser rule context.
- **int** (int) - Required - An integer representing the rule index.

### Response
#### Success Response (200)
- **ExprOrSeqContext** (com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprOrSeqContext) - The newly created `ExprOrSeqContext` object.

#### Response Example
{
  "example": "ExprOrSeqContext object"
}
```

--------------------------------

### getSerializedATN

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/path/generated/PathExpressionLexer.html

Gets the serialized form of the ATN (Abstract Syntax Tree) for the lexer.

```APIDOC
## getSerializedATN

### Description
Gets the serialized form of the ATN (Abstract Syntax Tree) for the lexer.

### Method
public java.lang.String getSerializedATN()

### Overrides
`getSerializedATN` in class `org.antlr.v4.runtime.Recognizer<java.lang.Integer,org.antlr.v4.runtime.atn.LexerATNSimulator>`
```

--------------------------------

### main

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/JSONataUtils.html

The main entry point for the JSONataUtils class. This method can be used to run the utility class from the command line, typically for testing or demonstration purposes.

```APIDOC
## main

### Description
Entry point for the JSONataUtils class. Executes the main functionality, often used for command-line execution or testing.

### Method Signature
public static void main(String[] args)

### Throws
* **java.lang.Exception** - If an error occurs during execution.
```

--------------------------------

### expr() - Get all expressions

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.LogandContext.html

Retrieves a list of all expression contexts within this LogandContext.

```APIDOC
## expr()

### Description
Retrieves a list of all expression contexts associated with this LogandContext.

### Returns
*   `java.util.List<MappingExpressionParser.ExprContext>` - A list of expression contexts.
```

--------------------------------

### getRuleIndex()

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-7.html

Method to get the rule index. Available in various contexts within MappingExpressionParser.

```APIDOC
## getRuleIndex()

### Description
Retrieves the rule index for the specific context.

### Method
Method

### Class
com.api.jsonata4java.expressions.generated.MappingExpressionParser.EmptyValuesContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprListContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprOrSeqContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprOrSeqListContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprValuesContext
com.api.jsonata4java.expressions.generated.MappingExpressionParser.FieldListContext
```

--------------------------------

### main Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/SumFunction.html

Entry point for the SumFunction class, typically used for testing or standalone execution.

```APIDOC
## main

### Description
Provides a static entry point for the SumFunction, often used for demonstration or testing purposes.

### Method
public static void main(java.lang.String[] args)
```

--------------------------------

### expr() - Get all expressions

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.LogorContext.html

Retrieves a list of all expression contexts associated with this logical OR operation.

```APIDOC
## expr()

### Description
Retrieves a list of all expression contexts associated with this logical OR operation.

### Returns
*   `java.util.List<MappingExpressionParser.ExprContext>` - A list of expression contexts.
```

--------------------------------

### expr() - Get all expressions

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.MembershipContext.html

Retrieves a list of all expression contexts associated with this membership context.

```APIDOC
## expr()

### Description
Returns a list of all `ExprContext` objects within this `MembershipContext`.

### Returns
*   `java.util.List<MappingExpressionParser.ExprContext>` - A list of expression contexts.
```

--------------------------------

### accept Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.NullContext.html

Accepts a visitor to process this context.

```APIDOC
## accept Method

### Description
Accepts a `ParseTreeVisitor` to visit this node.

### Parameters
*   **visitor** (`ParseTreeVisitor<? extends T>`) - The visitor to accept.

### Returns
*   **T** - The result of the visitor's visit.
```

--------------------------------

### expr(int i) - Get specific expression

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.LogandContext.html

Retrieves a specific expression context by its index.

```APIDOC
## expr(int i)

### Description
Retrieves a specific expression context from the list by its index.

### Parameters
*   **i** (int) - The index of the desired expression context.

### Returns
*   `MappingExpressionParser.ExprContext` - The expression context at the specified index.
```

--------------------------------

### MappingExpressionParser.ExprOrSeqListContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-5.html

Details the constructor for the `ExprOrSeqListContext` class.

```APIDOC
## POST /api/jsonata4java/expressions/generated/MappingExpressionParser/ExprOrSeqListContext

### Description
Constructs a new `ExprOrSeqListContext` instance.

### Method
POST

### Endpoint
/api/jsonata4java/expressions/generated/MappingExpressionParser/ExprOrSeqListContext

### Parameters
#### Request Body
- **parserRuleContext** (org.antlr.v4.runtime.ParserRuleContext) - Required - The parent parser rule context.
- **int** (int) - Required - An integer representing the rule index.

### Response
#### Success Response (200)
- **ExprOrSeqListContext** (com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprOrSeqListContext) - The newly created `ExprOrSeqListContext` object.

#### Response Example
{
  "example": "ExprOrSeqListContext object"
}
```

--------------------------------

### $substring(str, start [, length])

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/class-use/Function.html

Complies with javascript substr (and thus JSONata $substring).

```APIDOC
## $substring(str, start [, length])

### Description
Extracts a substring from a string. Complies with javascript substr (and thus JSONata $substring).

### Parameters
* **str** (string) - The string to extract from.
* **start** (number) - The starting index of the substring.
* **length** (number, optional) - The length of the substring to extract.
```

--------------------------------

### MappingExpressionParser.Array_constructorContext Methods

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-5.html

Details the `exprOrSeqList` method within the `MappingExpressionParser.Array_constructorContext` class.

```APIDOC
## GET /api/jsonata4java/expressions/generated/MappingExpressionParser/Array_constructorContext/exprOrSeqList

### Description
Retrieves a list of expressions or sequences within an array constructor.

### Method
GET

### Endpoint
/api/jsonata4java/expressions/generated/MappingExpressionParser/Array_constructorContext/exprOrSeqList

### Response
#### Success Response (200)
- **ExprOrSeqListContext** (com.api.jsonata4java.expressions.generated.MappingExpressionParser.ExprOrSeqListContext) - Description of the returned expression or sequence list context.

#### Response Example
{
  "example": "ExprOrSeqListContext object"
}
```

--------------------------------

### getRuleIndex Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.FieldListContext.html

Gets the rule index for this parser rule context. Overrides the method from RuleContext.

```APIDOC
public int getRuleIndex()
```

--------------------------------

### ExprOrSeqContext Methods

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ExprOrSeqContext.html

This section details the methods available on the ExprOrSeqContext object, including constructors and specific parser rule methods.

```APIDOC
## Constructor Detail

### ExprOrSeqContext

```java
public ExprOrSeqContext(org.antlr.v4.runtime.ParserRuleContext parent, int invokingState)
```

## Method Detail

### seq

```java
public MappingExpressionParser.SeqContext seq()
```

### expr

```java
public MappingExpressionParser.ExprContext expr()
```

### getRuleIndex

```java
public int getRuleIndex()
```

Overrides:
`getRuleIndex` in class `org.antlr.v4.runtime.RuleContext`

### enterRule

```java
public void enterRule(org.antlr.v4.runtime.tree.ParseTreeListener listener)
```

Overrides:
`enterRule` in class `org.antlr.v4.runtime.ParserRuleContext`

### exitRule

```java
public void exitRule(org.antlr.v4.runtime.tree.ParseTreeListener listener)
```

Overrides:
`exitRule` in class `org.antlr.v4.runtime.ParserRuleContext`

### accept

```java
public <T> T accept(org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T> visitor)
```

Specified by:
`accept` in interface `org.antlr.v4.runtime.tree.ParseTree`

Overrides:
`accept` in class `org.antlr.v4.runtime.RuleContext`
```

--------------------------------

### prompt (String, boolean)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/JSONataUtils.html

Prints a prompt and returns the user response, with optional trimming.

```APIDOC
## prompt (String, boolean)

### Description
Print the supplied prompt (if not null) and return the trimmed response according to the supplied trim control.

### Method Signature
`static java.lang.String prompt(java.lang.String strPrompt, boolean bTrim)`
```

--------------------------------

### expr(int i) - Get specific expression context

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ConditionalContext.html

Retrieves a specific expression context by its index.

```APIDOC
## expr(int i)

### Description
Returns the `ExprContext` at the specified index within this `ConditionalContext`.

### Parameters
*   **i** (`int`) - The index of the desired expression context.

### Returns
*   `MappingExpressionParser.ExprContext` - The expression context at the given index.
```

--------------------------------

### enterExprOrSeqList

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionListener.html

Enter a parse tree produced by MappingExpressionParser.exprOrSeqList().

```APIDOC
## enterExprOrSeqList

### Description
Enter a parse tree produced by `MappingExpressionParser.exprOrSeqList()`.

### Method Signature
`void enterExprOrSeqList(MappingExpressionParser.ExprOrSeqListContext ctx)`
```

--------------------------------

### expr() - Get all expression contexts

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ConditionalContext.html

Retrieves a list of all expression contexts associated with this conditional context.

```APIDOC
## expr()

### Description
Returns a list of all `ExprContext` objects within this `ConditionalContext`.

### Returns
*   `java.util.List<MappingExpressionParser.ExprContext>` - A list containing all expression contexts.
```

--------------------------------

### accept Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Sift_functionContext.html

Accepts a ParseTreeVisitor to process this context.

```APIDOC
## accept Method

### Description
Accepts a ParseTreeVisitor to process this context and return a result.

### Method Signature
`public <T> T accept(org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T> visitor)`

### Specified by
`accept` in interface `org.antlr.v4.runtime.tree.ParseTree`

### Overrides
`accept` in class `org.antlr.v4.runtime.RuleContext`
```

--------------------------------

### NowFunction.invoke

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/class-use/MappingExpressionParser.Function_callContext.html

Invokes the NowFunction to get the current date and time. It accepts an ExpressionsVisitor and a Function_callContext, returning a JsonNode.

```APIDOC
## NowFunction.invoke

### Description
Invokes the NowFunction to get the current date and time.

### Method Signature
`com.fasterxml.jackson.databind.JsonNode invoke(ExpressionsVisitor expressionVisitor, MappingExpressionParser.Function_callContext ctx)`
```

--------------------------------

### prompt

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-16.html

Prints the supplied prompt (if not null) and returns the trimmed response.

```APIDOC
## prompt

### Description
Print the supplied prompt (if not null) and return the trimmed response.

### Method Signature
`static String prompt(String prompt)`

### Class
`com.api.jsonata4java.JSONataUtils`
```

--------------------------------

### slice (without end)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/utils/ArrayUtils.html

Returns a shallow copy of the portion of the supplied array from the start index through the end of the array.

```APIDOC
## slice

### Description
Returns a shallow copy of the portion of the supplied array from start through the end of the array.

### Method
`public static com.fasterxml.jackson.databind.node.ArrayNode slice(com.fasterxml.jackson.databind.node.ArrayNode array, int start)`

### Parameters
#### Path Parameters
- **array** (com.fasterxml.jackson.databind.node.ArrayNode) - The input array to be sliced.
- **start** (int) - The starting index where the slice should occur.

### Returns
`com.fasterxml.jackson.databind.node.ArrayNode` - A shallow copy of the portion of the supplied array from start through the end of the array.
```

--------------------------------

### accept Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Var_recallContext.html

Accepts a visitor to visit the node.

```APIDOC
## accept Method

### Description
Accepts a visitor to visit the node.

### Specified by
*   `accept` in interface `org.antlr.v4.runtime.tree.ParseTree`

### Overrides
*   `accept` in class `org.antlr.v4.runtime.RuleContext`

### Parameters
*   **visitor** (org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T>) - The visitor to accept.

### Returns
*   T - The result of the visitor's visit.
```

--------------------------------

### slice (with end)

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/utils/ArrayUtils.html

Returns a shallow copy of the portion of the supplied array from the start index up to, but not including, the end index.

```APIDOC
## slice

### Description
Returns a shallow copy of the portion of the supplied array from start to end (not including end).

### Method
`public static com.fasterxml.jackson.databind.node.ArrayNode slice(com.fasterxml.jackson.databind.node.ArrayNode array, int start, int end)`

### Parameters
#### Path Parameters
- **array** (com.fasterxml.jackson.databind.node.ArrayNode) - The input array to be sliced.
- **start** (int) - The starting index of the slice.
- **end** (int) - The ending index of the slice (exclusive).

### Returns
`com.fasterxml.jackson.databind.node.ArrayNode` - A shallow copy of the specified portion of the array.
```

--------------------------------

### LogandContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.LogandContext.html

Initializes a new instance of the LogandContext class.

```APIDOC
## LogandContext Constructor

### Description
Initializes a new instance of the LogandContext class.

### Parameters
*   **ctx** (MappingExpressionParser.ExprContext) - The expression context to copy from.
```

--------------------------------

### prompt

Source: https://github.com/ibm/jsonata4java/blob/master/docs/index-files/index-16.html

Prints the supplied prompt (if not null) and returns the trimmed response according to the supplied trim control.

```APIDOC
## prompt

### Description
Print the supplied prompt (if not null) and return the trimmed response according to the supplied trim control.

### Method Signature
`static String prompt(String prompt, boolean trim)`

### Class
`com.api.jsonata4java.JSONataUtils`
```

--------------------------------

### CeilFunction.invoke

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/class-use/ExpressionsVisitor.html

Invokes the CeilFunction to get the ceiling value of a number in a mapping expression. It requires an ExpressionsVisitor and a Function_callContext, returning a JsonNode.

```APIDOC
## CeilFunction.invoke

### Description
Invokes the CeilFunction to get the ceiling value of a number in a mapping expression. It requires an ExpressionsVisitor and a Function_callContext, returning a JsonNode.

### Method Signature
`CeilFunction.invoke(ExpressionsVisitor expressionVisitor, MappingExpressionParser.Function_callContext ctx)`

### Parameters
- **expressionVisitor** (ExpressionsVisitor) - The visitor pattern implementation for expression traversal.
- **ctx** (MappingExpressionParser.Function_callContext) - The context of the function call.

### Returns
- `com.fasterxml.jackson.databind.JsonNode` - The result of the CeilFunction execution.
```

--------------------------------

### Sequence Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/Sequence.html

Initializes a new instance of the Sequence class.

```APIDOC
## Sequence()

### Description

Initializes a new instance of the Sequence class.

### Constructor

`Sequence()`
```

--------------------------------

### FloorFunction.invoke

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/class-use/ExpressionsVisitor.html

Invokes the FloorFunction to get the floor value of a JSON node. It takes an ExpressionsVisitor and a Function_callContext as input and returns a JsonNode.

```APIDOC
## FloorFunction.invoke

### Description
Invokes the FloorFunction to get the floor value of a JSON node.

### Method Signature
`invoke(ExpressionsVisitor expressionVisitor, MappingExpressionParser.Function_callContext ctx)`

### Parameters
- **expressionVisitor** (ExpressionsVisitor) - The visitor pattern implementation for expressions.
- **ctx** (MappingExpressionParser.Function_callContext) - The context of the function call.

### Returns
`com.fasterxml.jackson.databind.JsonNode` - The floor value of the input.
```

--------------------------------

### Percentage Formatting

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/test/expressions/FormatNumberFunctionTests.html

Shows how to format a number as a percentage using a picture string.

```jsonata
$formatNumber(0.14, "01%") == "14%"
```

--------------------------------

### ExprOrSeqListContext Methods

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.ExprOrSeqListContext.html

Provides access to the list of ExprOrSeqContext elements within this context.

```APIDOC
## ExprOrSeqListContext

### Description
Represents a list of expression or sequence contexts.

### Methods

#### exprOrSeq

```java
public java.util.List<MappingExpressionParser.ExprOrSeqContext> exprOrSeq()
```

Returns a list of all `ExprOrSeqContext` children.

#### exprOrSeq

```java
public MappingExpressionParser.ExprOrSeqContext exprOrSeq(int i)
```

Returns the `ExprOrSeqContext` at the specified index.

#### getRuleIndex

```java
public int getRuleIndex()
```

Overrides `getRuleIndex` in `org.antlr.v4.runtime.RuleContext`.

#### enterRule

```java
public void enterRule(org.antlr.v4.runtime.tree.ParseTreeListener listener)
```

Overrides `enterRule` in `org.antlr.v4.runtime.ParserRuleContext`.

#### exitRule

```java
public void exitRule(org.antlr.v4.runtime.tree.ParseTreeListener listener)
```

Overrides `exitRule` in `org.antlr.v4.runtime.ParserRuleContext`.

#### accept

```java
public <T> T accept(org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T> visitor)
```

Specified by `accept` in interface `org.antlr.v4.runtime.tree.ParseTree`.
Overrides `accept` in class `org.antlr.v4.runtime.RuleContext`.
```

--------------------------------

### getValuesListExpression

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/class-use/ExpressionsVisitor.html

Gets the expression at the specified index from the context's ExprValuesContext, preserving null values or returning null if the index is invalid.

```APIDOC
## getValuesListExpression

### Description
Gets the expression at the supplied index from the context's `MappingExpressionParser.ExprValuesContext` {@link ExprListContext}, preserving the null value (or returning null if the index is invalid).

### Method Signature
`static com.fasterxml.jackson.databind.JsonNode getValuesListExpression(ExpressionsVisitor exprVisitor, MappingExpressionParser.Function_callContext ctx, int index)`
```

--------------------------------

### accept Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.StringContext.html

Accepts a ParseTreeVisitor to process the StringContext.

```APIDOC
## accept Method

### Signature
public <T> T accept(org.antlr.v4.runtime.tree.ParseTreeVisitor<? extends T> visitor)

### Description
Accepts a visitor for the parse tree. This method allows for the implementation of the visitor pattern to perform operations on the parse tree nodes, including the StringContext.
```

--------------------------------

### $pad(str, width [, char])

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/package-summary.html

Returns a copy of the string with padding to meet a minimum width.

```APIDOC
## $pad(str, width [, char])

### Description
Returns a copy of the string str with extra padding, if necessary, so that its total number of characters is at least the absolute value of the width parameter.

### Method
Function

### Parameters
- **str** (string) - The input string.
- **width** (number) - The minimum desired width of the string.
- **char** (string, optional) - The character to use for padding. Defaults to a space.

### Response Example
{
  "example": "   123"
}
```

--------------------------------

### SubstringAfterFunction Usage

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/SubstringAfterFunction.html

The SubstringAfterFunction is used to get the portion of a string that appears after a specified delimiter. It supports using the context value if the primary string is not provided.

```APIDOC
## $substringAfter(str, chars)

### Description
Returns the substring after the first occurrence of the character sequence `chars` in `str`. If `str` is not specified (i.e., this function is invoked with only one argument), then the context value is used as the value of `str`. If `str` does not contain `chars`, then it returns `str`. An error is thrown if `str` and `chars` are not strings.

### Parameters

*   **str** (string) - The string to search within.
*   **chars** (string) - The character sequence to find.

### Examples

```jsonata
$substringAfter("Hello World", " ") == "World"
$substringAfter("Hello World", "o") == " World"
$substringAfter("Hello World", "xyz") == "Hello World"
```

### Error Handling

*   Throws an error if `str` or `chars` are not strings.
```

--------------------------------

### Thread-Safe Evaluation with evaluateSynced

Source: https://context7.com/ibm/jsonata4java/llms.txt

Use `evaluateSynced` to safely share a single `Expressions` instance across multiple threads. Ensure proper setup of `ObjectMapper` and `ExecutorService`.

```java
import com.api.jsonata4java.expressions.Expressions;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ThreadSafeExample {
    public static void main(String[] args) throws Exception {
        Expressions sharedExpr = Expressions.parse("$uppercase(name)");
        ObjectMapper mapper = new ObjectMapper();
        ExecutorService pool = Executors.newFixedThreadPool(4);

        String[] inputs = { "{\"name\":\"alice\"}", "{\"name\":\"bob\"}", "{\"name\":\"carol\"}" };
        for (String input : inputs) {
            JsonNode data = mapper.readTree(input);
            pool.submit(() -> {
                try {
                    // evaluateSynced is safe for concurrent access
                    JsonNode result = sharedExpr.evaluateSynced(data);
                    System.out.println(result.asText()); // "ALICE", "BOB", "CAROL"
                } catch (Exception e) {
                    e.printStackTrace();
                }
            });
        }
        pool.shutdown();
    }
}
```

--------------------------------

### StringContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.StringContext.html

Initializes a new instance of the StringContext class.

```APIDOC
## StringContext Constructor

### Signature
public StringContext(MappingExpressionParser.ExprContext ctx)

### Description
Initializes a new instance of the StringContext class, taking an ExprContext as an argument.
```

--------------------------------

### VarListContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.VarListContext.html

Initializes a new instance of the VarListContext class.

```APIDOC
public VarListContext(org.antlr.v4.runtime.ParserRuleContext parent, int invokingState)
```

--------------------------------

### $now()

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/package-summary.html

Generates a UTC timestamp in ISO 8601 compatible format and returns it as a string.

```APIDOC
## $now()

### Description
Generates a UTC timestamp in ISO 8601 compatible format and returns it as a string.

### Method
Function

### Parameters
None

### Response Example
{
  "example": "2023-10-27T10:30:00Z"
}
```

--------------------------------

### Evaluate JSONata Expression in Java

Source: https://github.com/ibm/jsonata4java/blob/master/.README.md.html

Example code demonstrating how to parse a JSON string into a JsonNode object and evaluate a JSONata expression against it. Requires Jackson library for JSON processing.

```java
package com.api.jsonata4java;

import java.io.IOException;

import com.api.jsonata4java.expressions.EvaluateException;
import com.api.jsonata4java.expressions.EvaluateRuntimeException;
import com.api.jsonata4java.expressions.Expressions;
import com.api.jsonata4java.expressions.ParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Test {

   public static void main(String[] args) {
      Expressions expr = null;
      ObjectMapper mapper = new ObjectMapper();
      JsonNode jsonObj = null;
      String json = "{ \"a\":1, \"b\":2, \"c\":[1,2,3,4,5] }";
      String expression = "$sum(c)";
      try {
         jsonObj = mapper.readTree(json);
      } catch (IOException e1) {
         e1.printStackTrace();
      }

      try {
         System.out.println("Using json:\n" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonObj));
         System.out.println("expression=" + expression);
         expr = Expressions.parse(expression);
      } catch (ParseException e) {
         System.err.println(e.getLocalizedMessage());
      } catch (EvaluateRuntimeException ere) {
         System.out.println(ere.getLocalizedMessage());
      } catch (JsonProcessingException e) {
         e.printStackTrace();
      }
      try {
         System.out.println("evaluate returns:");
         JsonNode result = expr.evaluate(jsonObj);
         if (result == null) {
            System.out.println("** no match **");
         } else {
            System.out.println("" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(result));
         }
      } catch (EvaluateException | JsonProcessingException e) {
         System.err.println(e.getLocalizedMessage());
      }
   }
}

```

--------------------------------

### $now()

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/class-use/Function.html

Generates a UTC timestamp in ISO 8601 compatible format and returns it as a string.

```APIDOC
## $now()

### Description
Generates a UTC timestamp in ISO 8601 compatible format and returns it as a string.
```

--------------------------------

### Create Bindings from JSON with Expression.createBindings

Source: https://context7.com/ibm/jsonata4java/llms.txt

Convert a JSON object into a list of Bindings. String values starting with 'function' become FUNCTION bindings; others become VARIABLE bindings.

```java
import com.api.jsonata4java.Binding;
import com.api.jsonata4java.Expression;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.List;

public class CreateBindingsExample {
    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        JsonNode bindingObj = mapper.readTree(
            "{\"threshold\": 100, \"label\": \"High\", \"tag\": \"function($v){ $v & \"-tag\" }\"}"
        );

        List<Binding> bindings = Expression.createBindings(bindingObj);
        // bindings[0]: VARIABLE $threshold = 100
        // bindings[1]: VARIABLE $label     = "High"
        // bindings[2]: FUNCTION $tag       = function($v){ $v & "-tag" }

        Expression expr = Expression.jsonata("$tag(label) & \" \" & $string(threshold)");
        JsonNode result = expr.evaluate(mapper.createObjectNode(), bindings);
        System.out.println(result.asText()); // "High-tag 100"
    }
}
```

--------------------------------

### Var_assignContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Var_assignContext.html

Initializes a new instance of the Var_assignContext class.

```APIDOC
## Var_assignContext Constructor

### Description
Initializes a new instance of the Var_assignContext class.

### Parameters
*   **ctx** (MappingExpressionParser.ExprContext) - The context for the expression.

### Signature
public Var_assignContext(MappingExpressionParser.ExprContext ctx)
```

--------------------------------

### Expression.createBindings(JsonNode)

Source: https://context7.com/ibm/jsonata4java/llms.txt

A static helper method to convert a JSON object into a list of `Binding` objects. String values starting with 'function' are treated as function bindings, others as variable bindings.

```APIDOC
## `Expression.createBindings(JsonNode jsonNode)`

### Description
This static helper method converts a JSON object into a `List<Binding>`. String values within the JSON object that start with the prefix `"function"` are interpreted as function declarations and create FUNCTION type bindings. All other string values, and non-string values, are treated as VARIABLE type bindings.

### Method
`Expression.createBindings`

### Parameters
#### Path Parameters
- **jsonNode** (JsonNode) - Required - The JSON object to convert into bindings.

### Request Example
```java
JsonNode bindingObj = mapper.readTree(
    "{\"threshold\": 100, \"label\": \"High\", \"tag\": \"function($v){ $v & \"-tag\" }\"}"
);

List<Binding> bindings = Expression.createBindings(bindingObj);
// bindings will contain:
// - VARIABLE $threshold = 100
// - VARIABLE $label     = "High"
// - FUNCTION $tag       = function($v){ $v & "-tag" }
```

### Response
Returns a `List<Binding>` representing the variables and functions defined in the input `JsonNode`.
```

--------------------------------

### Context_refContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Context_refContext.html

Initializes a new instance of the Context_refContext class.

```APIDOC
## Constructor: Context_refContext

### Description
Initializes a new instance of the Context_refContext class.

### Parameters
*   **ctx** (MappingExpressionParser.ExprContext) - The parent expression context.
```

--------------------------------

### Conditional Filtering with ContainsFunction

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/functions/ContainsFunction.html

Uses the $contains function within a predicate to filter a list of phone numbers, selecting only those that start with '077'. The context value 'number' is used as the string to check.

```jsonata
Phone[$contains(number, /^077/)]=={ "type": "mobile", "number": "077 7700 1234" }
```

--------------------------------

### prompt

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/JSONataUtils.html

Displays a prompt and returns the user's trimmed response.

```APIDOC
## prompt

### Description
Prints the supplied prompt (if not null) and returns the trimmed response.

### Method Signature
`public static String prompt(String strPrompt)`

### Parameters
#### Path Parameters
- **strPrompt** (java.lang.String) - The prompt to be displayed.

### Returns
The trimmed response to the prompt (may be the empty String ("" ) if nothing entered).
```

--------------------------------

### Execute JSONata Expression in Java

Source: https://github.com/ibm/jsonata4java/blob/master/README.md

This example demonstrates parsing a JSON string into a JsonNode, defining a JSONata expression, parsing the expression, and evaluating it against the JSON object. It includes error handling for parsing and evaluation exceptions.

```java
package com.api.jsonata4java;

import java.io.IOException;

import com.api.jsonata4java.expressions.EvaluateException;
import com.api.jsonata4java.expressions.EvaluateRuntimeException;
import com.api.jsonata4java.expressions.Expressions;
import com.api.jsonata4java.expressions.ParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Test {

   public static void main(String[\ ] args) {
      Expressions expr = null;
      ObjectMapper mapper = new ObjectMapper();
      JsonNode jsonObj = null;
      String json = "{ \"a\":1, \"b\":2, \"c\":[1,2,3,4,5] }";
      String expression = "$sum(c)";
      try {
         jsonObj = mapper.readTree(json);
      } catch (IOException e1) {
         e1.printStackTrace();
      }

      try {
         System.out.println("Using JSON:\n" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonObj));
         System.out.println("expression=" + expression);
         expr = Expressions.parse(expression);
      } catch (ParseException e) {
         System.err.println(e.getLocalizedMessage());
      } catch (EvaluateRuntimeException ere) {
         System.out.println(ere.getLocalizedMessage());
      } catch (JsonProcessingException e) {
         e.printStackTrace();
      }
      try {
         System.out.println("evaluate returns:");
         JsonNode result = expr.evaluate(jsonObj);
         if (result == null) {
            System.out.println("** no match **");
         } else {
            System.out.println("" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(result));
         }
      } catch (EvaluateException | JsonProcessingException e) {
         System.err.println(e.getLocalizedMessage());
      }
   }
}
```

--------------------------------

### Var_recallContext Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Var_recallContext.html

Initializes a new instance of the Var_recallContext class.

```APIDOC
## Var_recallContext Constructor

### Description
Initializes a new instance of the Var_recallContext class.

### Parameters
*   **ctx** (MappingExpressionParser.ExprContext) - The expression context to copy from.
```

--------------------------------

### enterRule Method

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.NullContext.html

Enters the rule for this context, notifying the listener.

```APIDOC
## enterRule Method

### Description
Called when entering the rule associated with this context. It notifies the provided `ParseTreeListener`.

### Parameters
*   **listener** (`ParseTreeListener`) - The listener to notify.
```

--------------------------------

### Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionLexer.html

Initializes a new instance of the MappingExpressionLexer with the specified character stream.

```APIDOC
## MappingExpressionLexer(CharStream input)

### Description
Constructs a new MappingExpressionLexer instance.

### Parameters
*   **input** (CharStream) - The character stream to be tokenized.
```

--------------------------------

### Demonstrate JSONata4Java Array Functions in Java

Source: https://context7.com/ibm/jsonata4java/llms.txt

This Java example shows how to use various JSONata built-in array functions such as $count, $append, $distinct, $sort, $reverse, $map, $filter, $reduce, and $zip with Expressions.parse().evaluate().

```java
import com.api.jsonata4java.expressions.Expressions;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;

public class ArrayFunctionsExample {
    public static void main(String[] args) throws Exception {
        JsonNode nil = JsonNodeFactory.instance.objectNode();
        JsonNode data = new ObjectMapper().readTree(
            "{\"orders\": [{\"id\":1,\"val\":10},{\"id\":2,\"val\":30},{\"id\":1,\"val\":20}]}"
        );

        // $count, $append, $distinct
        System.out.println(Expressions.parse("$count([1,2,3])").evaluate(nil));              // 3
        System.out.println(Expressions.parse("$append([1,2],[3,4])").evaluate(nil));         // [1,2,3,4]
        System.out.println(Expressions.parse("$distinct([1,2,1,3,2])").evaluate(nil));       // [1,2,3]
        System.out.println(Expressions.parse("$sort([3,1,2])").evaluate(nil));               // [1,2,3]
        System.out.println(Expressions.parse("$reverse([1,2,3])").evaluate(nil));            // [3,2,1]

        // $map with lambda
        System.out.println(Expressions.parse("$map([1..5], $string)").evaluate(nil));
        // ["1","2","3","4","5"]

        // $filter
        System.out.println(Expressions.parse(
            "$filter(orders, function($o){ $o.val > 15 })"
        ).evaluate(data));
        // [{"id":2,"val":30},{"id":1,"val":20}]

        // $reduce
        System.out.println(Expressions.parse(
            "$reduce([1,2,3,4], function($prev,$curr){ $prev + $curr })"
        ).evaluate(nil));
        // 10

        // $zip
        System.out.println(Expressions.parse("$zip([1,2,3],[\"a\",\"b\",\"c\"])").evaluate(nil));
        // [[1,"a"],[2,"b"],[3,"c"]]
    }
}
```

--------------------------------

### JSONata Legacy Regex Conversion Example

Source: https://github.com/ibm/jsonata4java/blob/master/README.md

Shows the conversion required for older JSONata4Java versions (<= 1.7.9) that used string literals for regex patterns. Convert string patterns to the '/<pattern>/' syntax for version 2.0.0 and later.

```jsonata
$replace("foo bar", "fo.*ar", "Foo Bar")
```

--------------------------------

### Comp_opContext Fields and Constructor

Source: https://github.com/ibm/jsonata4java/blob/master/docs/com/api/jsonata4java/expressions/generated/MappingExpressionParser.Comp_opContext.html

Details on the fields and constructor of the Comp_opContext class.

```APIDOC
## Comp_opContext Fields and Constructor

### Fields

#### op
```java
public org.antlr.v4.runtime.Token op
```

*   **Description**: The token representing the comparison operator.

### Constructor

#### Comp_opContext
```java
public Comp_opContext(MappingExpressionParser.ExprContext ctx)
```

*   **Description**: Constructs a `Comp_opContext` with the given expression context.
```