Tutorial 5: Error Handling and Debugging

Let's intentionally create errors to see how TatML helps you fix them.

Step 1: Create a Pattern with Errors

Create buggy_pattern.tatml:

pattern "Buggy Pattern" {
    ring1: R(5, p, 5)
    chain1: C(6, join(ring1.picot3), 6)  // Error: ring1 only has 1 picot
    ring2: R(2, join(ring2.picot1), 2)   // Error: can't join to self
    isolated: R(8, p, 8)                 // Warning: isolated element
}

Step 2: Run Validation

python3 tatml_validator.py buggy_pattern.tatml

You'll see helpful error messages:

❌ 2 Error(s):
  Element 'ring1' only has 1 picots, cannot access picot3
    Suggestion: Valid range: picot1 to picot1
  Ring 'ring2' cannot join to itself
    Suggestion: Rings cannot join to their own picots during construction

⚠️ 1 Warning(s):
  Element 'isolated' appears to be isolated
    Suggestion: Consider adding joins to connect this element to the pattern

Step 3: Fix the Errors

pattern "Fixed Pattern" {
    ring1: R(5, p, 5, p, 5)              // Added second picot
    chain1: C(6, join(ring1.picot2), 6)  // Fixed: now references valid picot
    ring2: R(4, join(chain1.picot1), 4)  // Fixed: joins to chain instead of self
    connector: C(6, join(ring2.picot1), 6, join(ring1.picot1), 6)  // Connected isolated element
}