Module strategy 

Integration strategy dispatcher

Orchestrates all integration techniques in optimal order (fast to slow).

Strategy Layers

1. Table lookup - O(1) exact pattern matching for common integrals
2. Rational functions - Partial fraction decomposition for P(x)/Q(x)
3. Function registry - Known antiderivatives (sin, cos, exp, ln, etc.)
4. Integration by parts - Product rule in reverse using LIATE heuristic
5. Substitution - Chain rule in reverse (u-substitution)
6. Trigonometric - Trig identities and power reduction formulas
7. Risch algorithm - Decision procedure for elementary functions
8. Basic rules - Power rule, constants, sums, constant multiples
9. Symbolic fallback - Return unevaluated integral expression

Strategy Tracking

To prevent infinite recursion, we track which strategies are currently active in the call stack. A strategy cannot recursively call itself.

Recursion Depth Limit

Maximum integration depth is 10 to prevent infinite recursion in pathological cases.

Structs

StrategyContext

Strategy execution context

Enums

IntegrationStrategy

Integration strategy identifier

Functions

integrate_with_strategy

Main integration strategy dispatcher

is_polynomial

Check if expression is a polynomial in the given variable

try_by_parts

Try integration by parts using the LIATE heuristic

try_registry_integration

Try function registry integration using known antiderivatives