Classify typed tickets

Build a deterministic business decision: classify a ticket by its overdue duration and select the first usable contact address. This walkthrough combines an enum, an optional, branches and a loop without a model or external service.

1. Write the program

Create triage.tb:

triage.tb

module examples.typed_triage

enum Priority
    normal
    watch
    urgent

type Triage
    priority is Priority
    contact is Optional of Text

function Classify
    takes days as Int
    gives Priority
    do
        if days >= 7
            give Priority.urgent
        else if days >= 3
            give Priority.watch
        else
            give Priority.normal

function FirstContact
    takes contacts as List of Optional of Text
    gives Optional of Text
    do
        for contact in contacts
            if present contact as address
                if address != ""
                    give some(address)
        give none(Text)

strategy Run
    takes days as Int
    takes contacts as List of Optional of Text
    gives Triage
    uses Classify
    uses FirstContact
    do
        Classify
            with days as days
            into priority
        FirstContact
            with contacts as contacts
            into contact
        give record Triage { priority as priority, contact as contact }

Functions calculate values; the strategy composes their results. No manifest or handler is needed.

2. Compile and run

touba compile triage.tb --out triage.air.json
touba run triage.air.json \
  --entry strategy:examples.typed_triage/Run \
  --inputs-json '{"days":8,"contacts":[{"present":false},{"present":true,"value":"a@example.test"}]}' \
  --output result

Expected result:

{"priority":"urgent","contact":{"present":true,"value":"a@example.test"}}

3. Check boundaries

Run the same command with these inputs:

Inputs	Expected result
{"days":3,"contacts":[]}	watch and {"present":false}
{"days":0,"contacts":[{"present":true,"value":""}]}	normal and {"present":false}
{"days":8,"contacts":[null]}	EntryInputSchemaInvalid refusal

Absence is not null. Empty text is present, but the business rule chooses to ignore it. These checks belong to different layers: the runtime validates the typed shape; the function expresses the project's rule.

Continue

See Enumerations, Optional values and Conditions and iteration, then automate these checks.

Build a readable notification

This standalone module adds an exhaustive label and a typed template. Here the application supplies a positive duration in minutes.

notification.tb

module examples.notification

enum Priority
    normal
    watch
    urgent

function Label
    takes priority as Priority
    gives Text
    do
        match priority
            case Priority.normal
                give "Normal"
            case Priority.watch
                give "Follow up"
            case Priority.urgent
                give "Urgent"

function Notify
    takes priority as Priority
    takes elapsed_minutes as Int
    gives Text
    do
        Label
            with priority as priority
            into label
        give f"{label}: {text(elapsed_minutes // 60)} h {text(elapsed_minutes % 60)} min"

touba compile notification.tb --out notification.air.json
touba run notification.air.json \
  --entry function:examples.notification/Notify \
  --inputs-json '{"priority":"urgent","elapsed_minutes":125}' \
  --output result

Result: "Urgent: 2 h 5 min". // computes the integer quotient and % the remainder. text(...) explicitly renders numbers inside the template. Removing a case reports NonExhaustiveMatch; inserting a number without text(...) is rejected. A template cannot resolve a secret by its name.