Enhance camel-datasonnet with utility functions and standard library

components/camel-datasonnet/src/main/docs/datasonnet-language.adoc

@@ -115,6 +115,120 @@ xref:ROOT:properties-component.adoc[Properties] component (property placeholders
 |cml.variable |the variable name |String |Will return the exchange variable.
 |===
 
+=== Null Handling Functions
+
+[width="100%",cols="20%,30%,50%",options="header",]
+|===
+|Function |Example |Description
+
+|cml.defaultVal(value, fallback) |`cml.defaultVal(body.currency, 'USD')` |Returns `value` if non-null, `fallback` otherwise.
+
+|cml.isEmpty(value) |`cml.isEmpty(body.name)` |Returns `true` if the value is null, an empty string, or an empty array.
+|===
+
+=== Type Coercion Functions
+
+[width="100%",cols="20%,30%,50%",options="header",]
+|===
+|Function |Example |Description
+
+|cml.toInteger(value) |`cml.toInteger('42')` |Converts a string or number to an integer. Returns null for null input.
+
+|cml.toDecimal(value) |`cml.toDecimal('3.14')` |Converts a string to a decimal number. Returns null for null input.
+
+|cml.toBoolean(value) |`cml.toBoolean('true')` |Converts a string (`true`/`false`/`yes`/`no`/`1`/`0`) or number to boolean. Returns null for null input.
+|===
+
+=== Date/Time Functions
+
+[width="100%",cols="20%,30%,50%",options="header",]
+|===
+|Function |Example |Description
+
+|cml.now() |`cml.now()` |Returns the current timestamp as an ISO-8601 string.
+
+|cml.nowFmt(format) |`cml.nowFmt('yyyy-MM-dd')` |Returns the current UTC time formatted with the given pattern.
+
+|cml.formatDate(value, format) |`cml.formatDate('2026-03-20T10:30:00Z', 'dd/MM/yyyy')` |Reformats an ISO-8601 date string using the given pattern. Returns null for null input.
+
+|cml.parseDate(value, format) |`cml.parseDate('20/03/2026', 'dd/MM/yyyy')` |Parses a date string into epoch milliseconds. Returns null for null input.
+|===
+
+=== Utility Functions
+
+[width="100%",cols="20%,30%,50%",options="header",]
+|===
+|Function |Example |Description
+
+|cml.uuid() |`cml.uuid()` |Generates a random UUID string.
+
+|cml.typeOf(value) |`cml.typeOf(body.x)` |Returns the type name: `string`, `number`, `boolean`, `object`, `array`, `null`, or `function`.
+|===
+
+=== Camel Standard Library (`camel.libsonnet`)
+
+Camel ships a standard library of helper functions that can be imported in any DataSonnet script:
+
+[source,java]
+----
+local c = import 'camel.libsonnet';
+{
+  total: c.sumBy(body.items, function(i) i.price * i.qty),
+  names: c.join(std.map(function(i) i.name, body.items), ', '),
+  topItem: c.first(c.sortBy(body.items, function(i) -i.price))
+}
+----
+
+==== String Helpers
+
+[width="100%",cols="30%,70%",options="header",]
+|===
+|Function |Description
+
+|`c.capitalize(s)` |Capitalizes the first letter.
+|`c.trim(s)` |Strips whitespace from both ends.
+|`c.split(s, sep)` |Splits a string by separator.
+|`c.join(arr, sep)` |Joins an array of strings with separator.
+|`c.contains(s, sub)` |Checks if string contains substring.
+|`c.startsWith(s, prefix)` |Checks if string starts with prefix.
+|`c.endsWith(s, suffix)` |Checks if string ends with suffix.
+|`c.replace(s, old, new)` |Replaces all occurrences.
+|`c.lower(s)` / `c.upper(s)` |Case conversion.
+|===
+
+==== Collection Helpers
+
+[width="100%",cols="30%,70%",options="header",]
+|===
+|Function |Description
+
+|`c.sum(arr)` |Sums all elements.
+|`c.sumBy(arr, f)` |Sums by applying function `f` to each element.
+|`c.first(arr)` / `c.last(arr)` |First/last element, or null if empty.
+|`c.count(arr)` |Array length.
+|`c.distinct(arr)` |Removes duplicates.
+|`c.flatMap(arr, f)` |Maps and flattens.
+|`c.sortBy(arr, f)` |Sorts by key function.
+|`c.groupBy(arr, f)` |Groups into object by key function.
+|`c.min(arr)` / `c.max(arr)` |Minimum/maximum element.
+|`c.take(arr, n)` / `c.drop(arr, n)` |First/last n elements.
+|`c.zip(a, b)` |Zips two arrays into pairs.
+|===
+
+==== Object Helpers
+
+[width="100%",cols="30%,70%",options="header",]
+|===
+|Function |Description
+
+|`c.pick(obj, keys)` |Selects only the listed keys.
+|`c.omit(obj, keys)` |Removes the listed keys.
+|`c.merge(a, b)` |Merges two objects (b overrides a).
+|`c.keys(obj)` / `c.values(obj)` |Object keys/values as arrays.
+|`c.entries(obj)` |Converts to `[{key, value}]` array.
+|`c.fromEntries(arr)` |Converts `[{key, value}]` array back to object.
+|===
+
 Here's an example showing some of these functions in use:
 
 [tabs]