source-academy / py-slang / 33252805903

86%

push

github

Fix the same pair()/llist() chain bug in the stepper's module interop (#451)

#450 fixed the CSE machine and py2js compiler's pythonToModule, but the
substitution stepper (src/conductor/stepper/moduleInterop.ts) has its own,
independent copy of this conversion logic, with the identical bug: llist(a, b)
is nested 2-element ArrayExpression nodes - ArrayExpression[a,
ArrayExpression[b, None]] - not the flat ArrayExpression[a, b] a literal
[a, b] produces. stepNodeToModule's "ArrayExpression" case mapped node.elements
1:1 regardless, so a chain crossed into a module as a 2-element ARRAY whose
second element was itself a nested sub-list.

Same fix, mirrored: isProperLlist (already used by lists.ts's own
head/tail/print_llist family) is now exported and gates a flattening walk that
only fires for a genuine chain terminating in None - a flat literal list, or a
raw 2-tuple, takes the exact same path as before, unchanged.

Confirms source-academy/modules#931 was hit on the Stepper evaluator too
(chapters 1-2 default to it), even after #450 fixed CSE/py2js.

4846 of 6083 branches covered (79.66%)

Branch coverage included in aggregate %.

10 of 10 new or added lines in 2 files covered. (100.0%)

10856 of 12245 relevant lines covered (88.66%)

161317.04 hits per line