RFC: Disambiguate Qualifier Syntax Semantics

[KrisSimon]

Problem

The colon syntax <name: qualifier> has three different meanings:

Context	Meaning	Example
Compute (ARO-0035)	Operation name	<Compute> the <len: length> from <text>.
Filter/Reduce	Type annotation	<Filter> the <users: List> from <data>...
Extract	Field access	<Extract> the <id> from the <event: user>.

Examples from Codebase

(* Qualifier = operation name - what operation to perform *)
<Compute> the <greeting-length: length> from the <greeting>.
(* From: Computations/main.aro:23 *)

(* Qualifier = type annotation - expected result type *)
<Reduce> the <count: Integer> from the <numbers> with count().
(* From: DataPipeline/main.aro:11 *)

(* Qualifier = field name - which field to extract *)
<Extract> the <user> from the <event: user>.
(* From: UserService/events.aro:6 *)

Issue

Same syntax, three semantics. Context-dependent parsing works but hurts readability.

Proposed Solutions

Option A: Different delimiters

• Operations: <result: operation> (keep current)
• Types: <result :: Type> (Haskell-style)
• Fields: <source.field> (dot notation)

Option B: Explicit keywords

• Operations: <result: length> (keep)
• Types: <result as Integer>
• Fields: <event: user> (keep)

Option C: Accept the overloading

• Document clearly that context determines meaning
• Keep single syntax for simplicity

Questions

1. Is disambiguation worth the complexity?
2. Which option preserves ARO's natural language feel?
3. Are there other qualifiers I've missed?