Reference Actions

Actions Reference

Complete reference for all built-in actions in ARO.

Quick Reference Table

Action	Role	Description	Example
Extract	REQUEST	Pull data from structured source	Extract the <id> from the <request: params>.
Retrieve	REQUEST	Fetch from repository	Retrieve the <user> from the <users> where id = <id>.
Request	REQUEST	Make HTTP request	Request the <data> from the <api-url>.
Read	REQUEST	Read from file	Read the <config> from the <file: "./config.json">.
List	REQUEST	List directory contents	List the <files> from the <directory: src-path>.
Stat	REQUEST	Get file metadata	Stat the <info> for the <file: "./doc.pdf">.
Exists	REQUEST	Check file existence	Exists the <found> for the <file: "./config.json">.
Exec	REQUEST	Execute shell command	Exec the <result> for the <command: "ls"> with "-la".
Prompt	REQUEST	Prompt user for terminal input	Prompt the <input> for "Enter your name: ".
Select	REQUEST	Present terminal selection menu	Select the <choice> from the <options> with "Pick one".
Create	OWN	Create new data	Create the <user> with { name: "Alice" }.
Compute	OWN	Perform calculations	Compute the <total> for the <items>.
Transform	OWN	Convert/map data	Transform the <dto> from the <entity>.
Validate	OWN	Check against rules	Validate the <data> for the <schema>.
Compare	OWN	Compare values	Compare the <hash> against the <stored>.
Clear	OWN	Clear the terminal screen	Clear the <terminal>.
Update	OWN	Modify existing data	Update the <user> with <changes>.
CreateDirectory	OWN	Create directory	Make the <directory> at the <path: "./out">.
Copy	OWN	Copy file/directory	Copy the <file: "./a.txt"> to the <destination: "./b.txt">.
Move	OWN	Move/rename file	Move the <file: "./old.txt"> to the <destination: "./new.txt">.
Map	OWN	Transform collection elements	Map the <names> from the <users: name>.
Filter	OWN	Select matching elements	Filter the <active> from the <users> where status = "active". where status not in <excluded>.
Reduce	OWN	Aggregate collection	Reduce the <total> as Float from the <items> with sum(<amount>).
Sort	OWN	Order collection	Sort the <users> by <name>.
Split	OWN	Split string by regex	Split the <parts> from the <string> by /,/.
Merge	OWN	Combine data	Merge the <existing-user> with <update-data>.
Return	RESPONSE	Return result	Return an <OK: status> with <data>.
Throw	RESPONSE	Throw error	Throw a <NotFound: error> for the <user>.
Log	EXPORT	Write to logs	Log "Done" to the <console>.
Store	EXPORT	Save to repository	Store the <user> into the <users>.
Write	EXPORT	Write to file	Write the <data> to the <file: "./out.txt">.
Append	EXPORT	Append to file	Append the <line> to the <file: "./log.txt">.
Send	EXPORT	Send to destination	Send the <email> to the <recipient>.
Emit	EXPORT	Emit domain event	Emit a <UserCreated: event> with <user>.
Publish	EXPORT	Make globally available	Publish as <config> <settings>.
Notify	EXPORT	Send notification	Notify the <alert> to the <admin>.
Delete	EXPORT	Remove data	Delete the <user> from the <users> where id = <id>.
Start	SERVICE	Start a service	Start the <http-server> with <contract>.
Stop	SERVICE	Stop a service	Stop the <http-server> with <application>.
Listen	SERVICE	Listen for connections	Listen on port 9000 as <socket-server>.
Connect	SERVICE	Connect to service	Connect to <host: "db"> on port 5432.
Close	SERVICE	Close connection	Close the <connection>.
Broadcast	SERVICE	Send to all connections	Broadcast the <msg> to the <server>.
Keepalive	SERVICE	Keep app running	Keepalive the <app> for the <events>.
Call	SERVICE	Call external API	Call the <result> via <API: POST /users>.
Accept	STATE	Accept state transition	Accept the <order: placed>.
Given	TEST	Test precondition	Given the <user> with { name: "Test" }.
When	TEST	Test action	When the <action> is performed.
Then	TEST	Test expectation	Then the <result> should be <expected>.
Assert	TEST	Assert condition	Assert the <value> equals <expected>.

Action Categories

Category	Role	Data Flow
REQUEST	Bring data in	External → Internal
OWN	Transform data	Internal → Internal
RESPONSE	Send results	Internal → External
EXPORT	Publish/persist	Internal → External
TERMINAL	Interactive UI	Terminal input and output
SERVICE	Control services	System operations
STATE	State transitions	Internal state changes
TEST	Testing	Verification actions

---

REQUEST Actions

Extract

Pulls data from a structured source.

Syntax:

Extract the <result> from the <source: property>.
Extract the <result: specifier> from the <list>.

Examples:

Extract the <user-id> from the <request: parameters>.
Extract the <body> from the <request: body>.
Extract the <token> from the <request: headers.Authorization>.
Extract the <email> from the <user: email>.
Extract the <order> from the <event: order>.

List Element Access:

Extract specific elements from arrays using result specifiers:

(* Keywords *)
Extract the <item: first> from the <list>.
Extract the <item: last> from the <list>.

(* Numeric index: 0 = last, 1 = second-to-last *)
Extract the <item: 0> from the <list>.
Extract the <item: 1> from the <list>.

(* Range: elements 2, 3, 4, 5 *)
Extract the <subset: 2-5> from the <list>.

(* Pick: elements at indices 0, 3, 7 *)
Extract the <selection: 0,3,7> from the <list>.

Specifier	Returns
first	First element
last	Last element
0	Last element (reverse indexing)
n	Element at (count - 1 - n)
2-5	Array of elements
0,3,7	Array of elements

Valid Prepositions: from

---

Retrieve

Fetches data from a repository.

Syntax:

Retrieve the <result> from the <repository> [where <condition>].

Examples:

Retrieve the <user> from the <user-repository>.
Retrieve the <user> from the <user-repository> where id = <user-id>.
Retrieve the <orders> from the <order-repository> where status = "pending".
Retrieve the <products> from the <repository> where category = <cat> and active = true.

Valid Prepositions: from

---

Request

Makes HTTP requests to external URLs or APIs.

Syntax:

Request the <result> from <url>.              (* GET request *)
Request the <result> to <url> with <data>.    (* POST request *)
Request the <result> via METHOD <url>.        (* Explicit method *)

Examples:

(* GET request *)
Create the <api-url> with "https://api.open-meteo.com/v1/forecast".
Request the <weather> from the <api-url>.

(* POST request *)
Create the <user-data> with { name: "Alice", email: "alice@example.com" }.
Request the <result> to the <api-url> with <user-data>.

(* PUT/DELETE/PATCH via explicit method *)
Request the <result> via PUT the <url> with <update-data>.
Request the <result> via DELETE the <url>.

Response Metadata: After a request, these variables are available:

• result - Parsed response body (JSON as map/list, or string)
• result.statusCode - HTTP status code (e.g., 200, 404)
• result.headers - Response headers as map
• result.isSuccess - Boolean: true if status 200-299

Valid Prepositions: from, to, via

---

Read

Reads from files with automatic format detection based on file extension.

Syntax:

Read the <result> from the <file: path>.
Read the <result: type> from the <file: path>.
Read the <result> from <path>.
Read the <result> from <path> with { options }.

Format Detection:

The file extension determines how content is parsed:

Extension	Parses To
.json	Object or Array
.jsonl, .ndjson	Array of Objects
.yaml, .yml	Object or Array
.toml	Object
.csv	Array of Objects (headers as keys)
.tsv	Array of Objects (headers as keys)
.xml	Object (nested)
.txt	Object (key=value pairs)
.log	String (write-only)
.env	Object (KEY=VALUE)
.obj, unknown	Binary Data

Examples:

(* Text file *)
Read the <content> from the <file: "./data.txt">.

(* JSON - automatically parsed *)
Read the <config> from "./settings.json".

(* JSON Lines - parsed to array *)
Read the <events> from "./logs/events.jsonl".

(* CSV - parsed with headers as keys *)
Read the <records> from "./data.csv".

(* YAML configuration *)
Read the <settings> from "./config.yaml".

(* Binary file *)
Read the <image: bytes> from the <file: "./logo.png">.

(* Bypass parsing - read as raw string *)
Read the <raw-json: String> from "./data.json".

(* CSV with custom options *)
Read the <data> from "./import.csv" with { delimiter: ";", header: false }.

CSV/TSV Options:

Option	Type	Default	Description
delimiter	String	, / \t	Field separator
header	Boolean	true	Expect header row
quote	String	"	Quote character

Valid Prepositions: from

---

Exec

Executes shell commands on the host system and returns structured results.

Syntax:

(* Preferred: command in object specifier *)
Exec the <result> for the <command: "uptime">.
Exec the <result> for the <command: "ls"> with "-la".
Exec the <result> for the <command: "ls"> with ["-l", "-a", "-h"].

(* Legacy: full command in with clause *)
Exec the <result> for the <command> with "command-string".
Exec the <result> for the <command> with <variable>.

(* Configuration object *)
Exec the <result> on the <system> with {
    command: "command-string",
    workingDirectory: "/path",
    timeout: 30000
}.

Result Object: The Exec action returns a structured result with the following fields:

• result.error - Boolean: true if command failed (non-zero exit code)
• result.message - Human-readable status message
• result.output - Command stdout (or stderr if error)
• result.exitCode - Process exit code (0 = success, -1 = timeout)
• result.command - The executed command string

Examples:

(* Preferred syntax *)
Exec the <listing> for the <command: "ls"> with "-la".
Return an <OK: status> for the <listing>.

(* With error handling *)
Exec the <result> for the <command: "df"> with "-h".
Log <result.message> to the <console> when <result.error> = true.
Return an <Error: status> for the <result> when <result.error> = true.
Return an <OK: status> for the <result>.

(* Using array for multiple arguments *)
Exec the <processes> for the <command: "ps"> with ["aux"].

(* With configuration options *)
Exec the <result> on the <system> with {
    command: "npm install",
    workingDirectory: "/app",
    timeout: 60000
}.

Configuration Options: When using object syntax, these options are available:

• command (required) - The shell command to execute
• workingDirectory - Working directory (default: current)
• timeout - Timeout in milliseconds (default: 30000)
• shell - Shell to use (default: /bin/sh)
• environment - Additional environment variables as object

Security Note: Be cautious when constructing commands from user input. Always validate and sanitize input to prevent command injection.

Valid Prepositions: for, on, with

---

OWN Actions

Create

Creates new data structures.

Syntax:

Create the <result> with <data>.

Examples:

Create the <user> with <user-data>.
Create the <response> with { message: "Success" }.
Create the <order> with {
    items: <items>,
    total: <total>,
    customer: <customer-id>
}.

Valid Prepositions: with

---

Compute

Performs calculations and data transformations.

Syntax:

Compute the <result> for the <input>.
Compute the <result> from <expression>.
Compute the <result: operation> from the <input>.
Compute the <result: operation> from <a> with <b>.

Built-in Operations:

Operation	Description	Example
length / count	Count elements	Compute the <len: length> from <text>.
uppercase	Convert to UPPERCASE	Compute the <upper: uppercase> from <text>.
lowercase	Convert to lowercase	Compute the <lower: lowercase> from <text>.
hash	Compute hash value	Compute the <h: hash> from <password>.
intersect	Elements in both	Compute the <common: intersect> from <a> with <b>.
difference	Elements in A not in B	Compute the <diff: difference> from <a> with <b>.
union	All unique elements	Compute the <all: union> from <a> with <b>.

Examples:

(* Basic operations *)
Compute the <total> for the <items>.
Compute the <hash> for the <password>.
Compute the <sum> from <a> + <b>.

(* Qualifier-as-name syntax *)
Compute the <greeting-length: length> from the <greeting>.
Compute the <farewell-length: length> from the <farewell>.

(* Set operations on lists *)
Create the <list-a> with [2, 3, 5].
Create the <list-b> with [1, 2, 3, 4].
Compute the <common: intersect> from <list-a> with <list-b>.
(* Result: [2, 3] *)

Compute the <only-in-a: difference> from <list-a> with <list-b>.
(* Result: [5] *)

(* Set operations on strings *)
Compute the <shared: intersect> from "hello" with "bello".
(* Result: "ello" *)

(* Set operations on objects (deep comparison) *)
Create the <obj-a> with { name: "Alice", age: 30 }.
Create the <obj-b> with { name: "Alice", age: 31 }.
Compute the <common: intersect> from <obj-a> with <obj-b>.
(* Result: { name: "Alice" } *)

Set Operation Type Behavior:

Operation	Lists	Strings	Objects
intersect	Elements in both (multiset)	Chars in both	Keys with matching values
difference	In A, not in B	Chars in A, not in B	Keys in A, not matching B
union	A preserved + unique from B	A preserved + unique from B	Merge (A wins conflicts)

Valid Prepositions: for, from, with

---

Transform

Converts or maps data.

Syntax:

Transform the <result> from the <source>.
Transform the <result> from the <source> with <modifications>.

Examples:

Transform the <dto> from the <entity>.
Transform the <updated-user> from the <user> with <updates>.
Transform the <response> from the <data>.

Valid Prepositions: from

---

Validate

Checks data against rules.

Syntax:

Validate the <data> for the <schema>.

Examples:

Validate the <user-data> for the <user-schema>.
Validate the <email> for the <email-pattern>.
Validate the <order> for the <order-rules>.

Valid Prepositions: for

---

Compare

Compares two values.

Syntax:

Compare the <value1> against the <value2>.

Examples:

Compare the <password-hash> against the <stored-hash>.
Compare the <signature> against the <expected>.

Valid Prepositions: against

---

Split

Splits a string into an array of parts using a regex delimiter.

Syntax:

Split the <parts> from the <string> by /delimiter/.

Examples:

(* Split CSV line by comma *)
Create the <csv-line> with "apple,banana,cherry".
Split the <fruits> from the <csv-line> by /,/.
(* fruits = ["apple", "banana", "cherry"] *)

(* Split by whitespace *)
Split the <words> from the <sentence> by /\s+/.

(* Split by multiple delimiters *)
Split the <tokens> from the <code> by /[;,\s]+/.

(* Case-insensitive split *)
Split the <sections> from the <text> by /SECTION/i.

Behavior:

• Returns an array of strings between delimiter matches
• If no match is found, returns original string as single-element array
• Empty strings included when delimiters are adjacent
• Supports regex flags: i (case-insensitive), s (dotall), m (multiline)

Valid Prepositions: from (with by clause)

---

Merge

Combines two data structures together. The source values are merged into the target, with source values overwriting target values for matching keys.

Syntax:

Merge the <target> with <source>.
Merge the <target> from <source>.

Examples:

(* Merge update data into existing entity *)
Retrieve the <existing-user> from the <user-repository> where id = <id>.
Extract the <update-data> from the <request: body>.
Merge the <existing-user> with <update-data>.
Store the <existing-user> into the <user-repository>.

(* Combine configuration objects *)
Merge the <defaults> with <overrides>.

(* Concatenate arrays *)
Merge the <all-items> with <new-items>.

(* Concatenate strings *)
Merge the <greeting> with <name>.

Supported Types:

• Dictionaries: Source keys overwrite target keys; other target keys preserved
• Arrays: Source elements appended to target array
• Strings: Source string concatenated to target string

Valid Prepositions: with, into, from

---

Filter

Selects elements from a collection that match a predicate.

Syntax:

Filter the <result> from the <collection> where <condition>.

Comparison Operators:

Operator	Description	Example
is, =	Equality	<status> is "active"
is not, !=	Inequality	<role> is not "guest"
>, >=, <, <=	Comparison	<age> >= 18
in	Set membership	<status> in ["a", "b"]
not in	Set exclusion	<status> not in <excluded>
between	Range	<price> between 10 and 100
contains	Substring	<name> contains "test"
starts with	Prefix match	<email> starts with "admin"
ends with	Suffix match	<file> ends with ".pdf"
matches	Regex pattern	<email> matches /^admin@/i

Examples:

(* Basic filtering *)
Filter the <admins> from the <users>
    where <role> is "admin".

Filter the <high-value> from the <orders>
    where <amount> > 1000.

(* Multiple conditions *)
Filter the <active-premium> from the <users>
    where <status> is "active" and <tier> is "premium".

(* Set membership with CSV string *)
Filter the <pending> from the <orders>
    where <status> in "pending,processing".

(* Set membership with array variable *)
Create the <exclude-statuses> with ["cancelled", "refunded"].
Filter the <active> from the <orders>
    where <status> not in <exclude-statuses>.

(* Combined with other conditions *)
Filter the <valid-orders> from the <orders>
    where <amount> > 0 and <status> not in <exclude-statuses>.

(* Regex matching *)
Filter the <admins> from the <users>
    where <email> matches /^admin@|@admin\./i.

Set Membership Notes:

• The in and not in operators accept either a CSV string or an array variable
• CSV string syntax: <field> in "value1,value2,value3"
• Array syntax: <field> not in <array-variable>

Valid Prepositions: from (with where clause)

---

RESPONSE Actions

Return

Returns a result with status.

Syntax:

Return [article] <status> [with <data>] [for <context>].

Examples:

Return an <OK: status> with <data>.
Return a <Created: status> with <resource>.
Return a <NoContent: status> for the <deletion>.
Return a <BadRequest: status> with <errors>.
Return a <NotFound: status> for the <missing: user>.

Valid Prepositions: with, for

---

Throw

Throws an error.

Syntax:

Throw [article] <error-type> for the <context>.

Examples:

Throw a <ValidationError> for the <invalid: input>.
Throw a <NotFoundError> for the <missing: user>.
Throw an <AuthenticationError> for the <invalid: token>.

Valid Prepositions: for

---

EXPORT Actions

Store

Saves data to a repository. Triggers repository observers for new entries and updates.

Syntax:

Store the <data> into the <repository>.

Examples:

Store the <user> into the <user-repository>.
Store the <order> into the <order-repository>.

Observer Event Behavior:

Scenario	Observer Event	new-entry Value
New entry	created fires	1
Update (same ID, different value)	updated fires	0
Duplicate (same value)	No event	0

• Deduplication: Storing the same value twice is a no-op — no event fires
• Variable binding: Binds new-entry to 1 (new) or 0 (duplicate/update)

List Storage:

When storing a List, Store triggers one observer event per item:

(* Store a list of users - triggers observer for EACH user *)
Store the <users: List> into the <user-repository>.

(Process User: user-repository Observer) {
    (* Receives ONE user, not the entire list *)
    Extract the <user> from the <event: newValue>.
    Return an <OK: status> for the <processing>.
}

Best Practice: Use repository observers to react to stored data rather than combining Store with Emit. See Guide-Repositories for patterns.

Valid Prepositions: into

---

Publish

Makes variables globally available.

Syntax:

Publish as <alias> <variable>.

Examples:

Publish as <app-config> <config>.
Publish as <current-user> <user>.

Valid Prepositions: as

---

Log

Writes to logs.

Syntax:

Log <value> to the <destination>.

Examples:

Log "User logged in" to the <console>.
Log <error> to the <console>.
Log <details> to the <audit-log>.

Valid Prepositions: to

---

Send

Sends data to external destinations.

Syntax:

Send the <data> to the <destination>.
Send the <data> to the <destination> with <content>.

Examples:

Send the <email> to the <user: email>.
Send the <notification> to the <push-service>.
Send the <data> to the <connection>.
Send the <message> to the <connection> with "Hello".

Valid Prepositions: to, with

---

Emit

Emits domain events.

Syntax:

Emit [article] <event-type: event> with <data>.

Examples:

Emit a <UserCreated: event> with <user>.
Emit an <OrderPlaced: event> with <order>.
Emit a <PaymentProcessed: event> with <payment>.

Valid Prepositions: with

---

Write

Writes to files with automatic format detection based on file extension.

Syntax:

Write the <data> to the <file: path>.
Write the <data> to <path>.
Write the <data> to <path> with { options }.

Format Detection:

The file extension determines the output format:

Extension	Format	Output
.json	JSON	Pretty-printed JSON
.jsonl, .ndjson	JSON Lines	One JSON object per line
.yaml, .yml	YAML	Human-readable YAML
.toml	TOML	TOML tables
.csv	CSV	Comma-separated with headers
.tsv	TSV	Tab-separated with headers
.xml	XML	XML with variable name as root
.md	Markdown	Markdown table
.html	HTML	HTML table element
.txt	Plain Text	key=value pairs
.sql	SQL	INSERT statements
.log	Log	Date-prefixed entries
.env	Environment	KEY=VALUE format
.obj, unknown	Binary	Raw bytes

Examples:

(* Text file *)
Write the <content> to the <file: "./output.txt">.

(* JSON - automatically serialized *)
Write the <users> to "./output/users.json".

(* JSON Lines - compact, one per line *)
Write the <events> to "./logs/events.jsonl".

(* CSV - spreadsheet friendly *)
Write the <report> to "./export/report.csv".

(* YAML - human readable *)
Write the <config> to "./settings.yaml".

(* XML - variable name becomes root element *)
Write the <products> to "./catalog/products.xml".

(* Markdown table *)
Write the <summary> to "./docs/summary.md".

(* SQL INSERT statements *)
Write the <users> to "./backup/users.sql".

(* CSV with custom options *)
Write the <data> to "./export.csv" with { delimiter: ";", header: false }.

CSV/TSV Options:

Option	Type	Default	Description
delimiter	String	, / \t	Field separator
header	Boolean	true	Include header row
quote	String	"	Quote character

Valid Prepositions: to

---

Append

Appends content to a file.

Syntax:

Append the <data> to the <file: path>.

Examples:

Append the <log-line> to the <file: "./logs/app.log">.
Append the <entry> to the <file: "./data.txt">.

Valid Prepositions: to, into

---

List

Lists directory contents.

Syntax:

Create the <dir-path> with "./path".
List the <result> from the <directory: dir-path>.
List the <result> from the <directory: dir-path> matching "pattern".
List the <result> from the <directory: dir-path> recursively.

Examples:

Create the <uploads-path> with "./uploads".
List the <entries> from the <directory: uploads-path>.
List the <aro-files> from the <directory: src-path> matching "*.aro".
List the <all-files> from the <directory: project-path> recursively.

Valid Prepositions: from

---

Stat

Gets file or directory metadata.

Syntax:

Stat the <result> for the <file: path>.
Stat the <result> for the <directory: path>.

Examples:

Stat the <info> for the <file: "./document.pdf">.
Stat the <dir-info> for the <directory: "./src">.

Result Properties:

• name - file or directory name
• path - full path
• size - size in bytes
• isFile - true if file
• isDirectory - true if directory
• created - creation date (ISO 8601)
• modified - modification date (ISO 8601)
• permissions - Unix-style permissions

Valid Prepositions: for

---

Exists

Checks if a file or directory exists.

Syntax:

Exists the <result> for the <file: path>.
Exists the <result> for the <directory: path>.

Examples:

Exists the <found> for the <file: "./config.json">.
Exists the <dir-exists> for the <directory: "./output">.

Valid Prepositions: for

---

CreateDirectory

Creates a directory with all intermediate directories.

Verbs: createdirectory, mkdir, make

Syntax:

Make the <directory> at the <path: path>.
CreateDirectory the <result> to the <path: path>.

Examples:

(* Natural syntax with "make" verb *)
Make the <directory> at the <path: "./output/reports/2024">.

(* Traditional syntax *)
CreateDirectory the <output-dir> to the <path: "./output/reports/2024">.

Valid Prepositions: at, to, for

---

Copy

Copies files or directories.

Syntax:

Copy the <file: source> to the <destination: dest>.
Copy the <directory: source> to the <destination: dest>.

Examples:

Copy the <file: "./template.txt"> to the <destination: "./copy.txt">.
Copy the <directory: "./src"> to the <destination: "./backup/src">.

Valid Prepositions: to

---

Move

Moves or renames files and directories.

Syntax:

Move the <file: source> to the <destination: dest>.
Move the <directory: source> to the <destination: dest>.

Examples:

Move the <file: "./draft.txt"> to the <destination: "./final.txt">.
Move the <directory: "./temp"> to the <destination: "./processed">.

Valid Prepositions: to

---

Delete

Removes data.

Syntax:

Delete the <target> from the <source> [where <condition>].
Delete the <file: path>.

Examples:

Delete the <user> from the <user-repository> where id = <user-id>.
Delete the <file: "./temp.txt">.
Delete the <sessions> from the <repository> where expired = true.

Valid Prepositions: from

---

Notify

Sends a notification to a recipient. Supports single recipients and collections.

Syntax:

Notify the <recipient> with "message".
Notify the <recipient> with <message-variable>.

Examples:

(* Notify a single user *)
Notify the <user> with "Your order has been shipped.".

(* Notify a collection - dispatches one notification per item *)
Notify the <subscribers> with "System maintenance at midnight.".

Handler Guards:

Use a when clause on the handler declaration to filter which notifications it processes:

(Send Alert: NotificationSent Handler) when <age> >= 18 {
    Extract the <user> from the <event: user>.
    Send the <email> to the <user: email>.
    Return an <OK: status> for the <notification>.
}

The guard is evaluated before the handler body executes. If the condition is false, the handler is silently skipped. The target object's fields are available directly in the condition expression.

Event Payload: When Notify fires, the NotificationSent event carries:

• event["user"] - the target recipient object
• event["message"] - the notification message

Valid Prepositions: with

---

TERMINAL Actions

Prompt

Prompts the user for text input in the terminal.

Syntax:

Prompt the <result> for "prompt text".
Prompt the <result> for <prompt-variable>.

Examples:

Prompt the <name> for "Enter your name: ".
Prompt the <password> for "Password: ".
Prompt the <choice> for "Continue? (y/n): ".

Valid Prepositions: for

---

Select

Presents a selection menu in the terminal and returns the chosen item.

Syntax:

Select the <result> from the <options> with "title".
Select the <result> from the <options> with <title-variable>.

Examples:

Create the <colors> with ["Red", "Green", "Blue"].
Select the <color> from the <colors> with "Choose a color".

Create the <sizes> with ["Small", "Medium", "Large"].
Select the <size> from the <sizes> with "Select size".

Valid Prepositions: from, with

---

Clear

Clears the terminal screen.

Syntax:

Clear the <terminal>.

Examples:

Clear the <terminal>.

Valid Prepositions: None

---

SERVICE Actions

Start

Starts a service. All services use the standardized with preposition for configuration.

Syntax:

Start the <service> with <configuration>.

Examples:

(* HTTP server from OpenAPI contract *)
Start the <http-server> with <contract>.

(* Socket server with port configuration *)
Start the <socket-server> with { port: 9000 }.

(* File monitor with directory path *)
Start the <file-monitor> with ".".
Start the <file-monitor> with { directory: "./data" }.

Valid Prepositions: with

---

Stop

Stops a service gracefully.

Syntax:

Stop the <service> with <context>.

Examples:

Stop the <http-server> with <application>.
Stop the <socket-server> with <application>.
Stop the <file-monitor> with <application>.

Valid Prepositions: with

---

Listen

Listens for connections.

Syntax:

Listen on port <number> as <name>.

Examples:

Listen on port 9000 as <socket-server>.

Valid Prepositions: on, as

---

Connect

Connects to a service.

Syntax:

Connect to <host: address> on port <number> as <name>.

Examples:

Connect to <host: "localhost"> on port 5432 as <database>.
Connect to <host: "redis.local"> on port 6379 as <cache>.

Valid Prepositions: to, on, as

---

Close

Closes connections.

Syntax:

Close the <connection>.

Examples:

Close the <database-connections>.
Close the <socket-server>.
Close the <connection>.

Valid Prepositions: None

---

Call

Makes API calls.

Syntax:

Call the <result> via <api-reference> [with <data>].

Examples:

Call the <result> via <UserAPI: POST /users> with <user-data>.
Call the <response> via <PaymentAPI: POST /charge> with <payment>.

Valid Prepositions: via, with

---

Broadcast

Sends to all connections.

Syntax:

Broadcast the <message> to the <server>.

Examples:

Broadcast the <message> to the <socket-server>.
Broadcast the <notification> to the <chat-server> with "User joined".

Valid Prepositions: to, with

---

Keepalive

Keeps a long-running application alive to process events.

Syntax:

Keepalive the <application> for the <events>.

Description: The Keepalive action blocks execution until a shutdown signal is received (SIGINT/SIGTERM). This is essential for applications that need to stay alive and process events, such as HTTP servers, file watchers, and socket servers.

Examples:

(Application-Start: My Server) {
    Start the <http-server> with <contract>.
    Keepalive the <application> for the <events>.
    Return an <OK: status> for the <startup>.
}

(Application-Start: File Watcher) {
    Start the <file-monitor> with "./watched".
    Keepalive the <application> for the <events>.
    Return an <OK: status> for the <startup>.
}

Valid Prepositions: for

---

Action Summary Table

Action	Role	Prepositions
Extract	REQUEST	from
Retrieve	REQUEST	from
Request	REQUEST	from, to, via
Read	REQUEST	from
Exec	REQUEST	for, on, with
Create	OWN	with
Compute	OWN	for, from
Transform	OWN	from
Validate	OWN	for
Compare	OWN	against
Update	OWN	with
Map	OWN	from
Filter	OWN	from, where
Reduce	OWN	from, with
Sort	OWN	by
Split	OWN	from (by clause)
Merge	OWN	with, into, from
Return	RESPONSE	with, for
Throw	RESPONSE	for
Store	EXPORT	into
Publish	EXPORT	as
Log	EXPORT	to
Send	EXPORT	to, with
Emit	EXPORT	with
Write	EXPORT	to
Delete	EXPORT	from
Notify	EXPORT	with
Prompt	TERMINAL	for
Select	TERMINAL	from, with
Clear	TERMINAL	-
List	FILE	from
Stat	FILE	for
Exists	FILE	for
CreateDirectory	FILE	to
Copy	FILE	to
Move	FILE	to
Append	FILE	to
Start	SERVICE	with
Stop	SERVICE	with
Listen	SERVICE	on, as
Connect	SERVICE	to, on, as
Close	SERVICE	-
Call	SERVICE	via, with
Broadcast	SERVICE	to, with
Keepalive	SERVICE	for
Accept	STATE	-
Given	TEST	with
When	TEST	-
Then	TEST	-
Assert	TEST	equals, contains