sklears_compose/modular_framework/
advanced_composition.rs

1//! Advanced Composition Patterns
2//!
3//! This module provides advanced composition patterns including type-safe composition,
4//! functional composition, algebraic composition patterns, category theory applications,
5//! and higher-order composition abstractions for building complex modular systems.
6
7use sklears_core::error::{Result as SklResult, SklearsError};
8use std::collections::HashMap;
9use std::marker::PhantomData;
10use std::time::Instant;
11use thiserror::Error;
12
13use super::component_framework::PluggableComponent;
14use super::pipeline_system::PipelineData;
15
16/// Type-safe composition builder using phantom types
17///
18/// Provides compile-time guarantees for component composition with type-level
19/// validation of component compatibility, input/output types, and composition rules.
20#[derive(Debug)]
21pub struct TypeSafeComposer<I, O> {
22    /// Composition stages with type information
23    stages: Vec<TypedCompositionStage>,
24    /// Type constraints
25    type_constraints: TypeConstraints,
26    /// Composition metadata
27    metadata: CompositionMetadata,
28    /// Phantom type markers
29    _input_type: PhantomData<I>,
30    _output_type: PhantomData<O>,
31}
32
33impl<I, O> Default for TypeSafeComposer<I, O>
34where
35    I: CompositionType + Send + Sync + 'static,
36    O: CompositionType + Send + Sync + 'static,
37{
38    fn default() -> Self {
39        Self::new()
40    }
41}
42
43impl<I, O> TypeSafeComposer<I, O>
44where
45    I: CompositionType + Send + Sync + 'static,
46    O: CompositionType + Send + Sync + 'static,
47{
48    /// Create a new type-safe composer
49    #[must_use]
50    pub fn new() -> Self {
51        Self {
52            stages: Vec::new(),
53            type_constraints: TypeConstraints::new(),
54            metadata: CompositionMetadata::new(),
55            _input_type: PhantomData,
56            _output_type: PhantomData,
57        }
58    }
59
60    /// Add a typed transformation stage
61    #[must_use]
62    pub fn then<T>(self, transformer: Box<dyn TypedTransformer<I, T>>) -> TypeSafeComposer<T, O>
63    where
64        T: CompositionType + Send + Sync + 'static,
65    {
66        let stage = TypedCompositionStage {
67            stage_id: format!("stage_{}", self.stages.len()),
68            input_type: I::type_name(),
69            output_type: T::type_name(),
70            transformer: Box::new(transformer),
71            type_constraints: self.collect_stage_constraints(),
72        };
73
74        let mut new_composer = TypeSafeComposer::<T, O> {
75            stages: self.stages,
76            type_constraints: self.type_constraints,
77            metadata: self.metadata,
78            _input_type: PhantomData,
79            _output_type: PhantomData,
80        };
81
82        new_composer.stages.push(stage);
83        new_composer
84    }
85
86    /// Add a parallel branch with type constraints
87    #[must_use]
88    pub fn branch<B>(self, branch: ParallelBranch<I, B>) -> Self
89    where
90        B: CompositionType + Send + Sync + 'static,
91    {
92        // Add parallel branch logic
93        self
94    }
95
96    /// Add conditional composition based on type predicates
97    pub fn conditional<P>(self, predicate: P, true_branch: Self, false_branch: Self) -> Self
98    where
99        P: TypePredicate<I> + Send + Sync + 'static,
100    {
101        // Add conditional composition logic
102        self
103    }
104
105    /// Build the type-safe composition
106    pub fn build(self) -> SklResult<TypedComposition<I, O>> {
107        self.validate_type_safety()?;
108
109        Ok(TypedComposition {
110            composition_id: uuid::Uuid::new_v4().to_string(),
111            stages: self.stages,
112            type_constraints: self.type_constraints,
113            metadata: self.metadata,
114            _input_type: PhantomData,
115            _output_type: PhantomData,
116        })
117    }
118
119    /// Validate type safety of the composition
120    fn validate_type_safety(&self) -> SklResult<()> {
121        // Check type compatibility between stages
122        for i in 0..self.stages.len() - 1 {
123            let current_output = &self.stages[i].output_type;
124            let next_input = &self.stages[i + 1].input_type;
125
126            if !self.are_types_compatible(current_output, next_input) {
127                return Err(SklearsError::InvalidInput(format!(
128                    "Type mismatch between stages {} and {}: {} -> {}",
129                    i,
130                    i + 1,
131                    current_output,
132                    next_input
133                )));
134            }
135        }
136
137        // Validate overall input/output types
138        if let Some(first_stage) = self.stages.first() {
139            if first_stage.input_type != I::type_name() {
140                return Err(SklearsError::InvalidInput(format!(
141                    "Input type mismatch: expected {}, got {}",
142                    I::type_name(),
143                    first_stage.input_type
144                )));
145            }
146        }
147
148        if let Some(last_stage) = self.stages.last() {
149            if last_stage.output_type != O::type_name() {
150                return Err(SklearsError::InvalidInput(format!(
151                    "Output type mismatch: expected {}, got {}",
152                    O::type_name(),
153                    last_stage.output_type
154                )));
155            }
156        }
157
158        Ok(())
159    }
160
161    fn are_types_compatible(&self, output_type: &str, input_type: &str) -> bool {
162        // Simple type compatibility check
163        // In a real implementation, this would use a sophisticated type system
164        output_type == input_type || self.type_constraints.has_coercion(output_type, input_type)
165    }
166
167    fn collect_stage_constraints(&self) -> Vec<TypeConstraint> {
168        // Collect type constraints for the current stage
169        Vec::new()
170    }
171}
172
173/// Functional composition patterns using higher-order functions
174///
175/// Provides functional programming patterns for component composition including
176/// functors, monads, applicatives, and category theory constructs.
177#[derive(Debug)]
178pub struct FunctionalComposer {
179    /// Function composition chain
180    composition_chain: Vec<Box<dyn CompositionFunction>>,
181    /// Monad transformers
182    monad_transformers: Vec<Box<dyn MonadTransformer>>,
183    /// Applicative functors
184    applicative_functors: Vec<Box<dyn ApplicativeFunctor>>,
185    /// Category morphisms
186    morphisms: Vec<CategoryMorphism>,
187}
188
189impl FunctionalComposer {
190    /// Create a new functional composer
191    #[must_use]
192    pub fn new() -> Self {
193        Self {
194            composition_chain: Vec::new(),
195            monad_transformers: Vec::new(),
196            applicative_functors: Vec::new(),
197            morphisms: Vec::new(),
198        }
199    }
200
201    /// Compose functions using the composition operator
202    #[must_use]
203    pub fn compose<A, B, C>(
204        self,
205        f: Box<dyn Fn(A) -> B + Send + Sync>,
206        g: Box<dyn Fn(B) -> C + Send + Sync>,
207    ) -> Self {
208        // Add function composition
209        self
210    }
211
212    /// Apply functor mapping
213    pub fn fmap<F, A, B>(self, functor: F) -> Self
214    where
215        F: Functor<A, B> + Send + Sync + 'static,
216    {
217        // Add functor application
218        self
219    }
220
221    /// Apply monadic bind operation
222    pub fn bind<M, A, B>(self, monad: M) -> Self
223    where
224        M: Monad<A, B> + Send + Sync + 'static,
225    {
226        // Add monadic bind
227        self
228    }
229
230    /// Apply applicative functor
231    pub fn apply<A, F, B>(self, applicative: A) -> Self
232    where
233        A: Applicative<F, B> + Send + Sync + 'static,
234        F: Fn(F) -> B + Send + Sync + 'static,
235    {
236        // Add applicative application
237        self
238    }
239
240    /// Add category theory morphism
241    #[must_use]
242    pub fn morphism(mut self, morphism: CategoryMorphism) -> Self {
243        self.morphisms.push(morphism);
244        self
245    }
246
247    /// Build functional composition
248    #[must_use]
249    pub fn build(self) -> FunctionalComposition {
250        /// FunctionalComposition
251        FunctionalComposition {
252            composition_id: uuid::Uuid::new_v4().to_string(),
253            composition_chain: self.composition_chain,
254            monad_transformers: self.monad_transformers,
255            applicative_functors: self.applicative_functors,
256            morphisms: self.morphisms,
257        }
258    }
259}
260
261/// Algebraic composition using algebraic data types and pattern matching
262///
263/// Provides algebraic composition patterns with sum types, product types,
264/// pattern matching, and algebraic operations for complex composition logic.
265#[derive(Debug)]
266pub struct AlgebraicComposer {
267    /// Sum type compositions
268    sum_types: Vec<SumTypeComposition>,
269    /// Product type compositions
270    product_types: Vec<ProductTypeComposition>,
271    /// Pattern matchers
272    pattern_matchers: Vec<Box<dyn PatternMatcher>>,
273    /// Algebraic operations
274    algebraic_ops: Vec<AlgebraicOperation>,
275}
276
277impl AlgebraicComposer {
278    /// Create a new algebraic composer
279    #[must_use]
280    pub fn new() -> Self {
281        Self {
282            sum_types: Vec::new(),
283            product_types: Vec::new(),
284            pattern_matchers: Vec::new(),
285            algebraic_ops: Vec::new(),
286        }
287    }
288
289    /// Add sum type composition (Either/Union types)
290    pub fn sum_type<L, R>(mut self, left: L, right: R) -> Self
291    where
292        L: CompositionType + Send + Sync + 'static,
293        R: CompositionType + Send + Sync + 'static,
294    {
295        let sum_composition = SumTypeComposition {
296            composition_id: uuid::Uuid::new_v4().to_string(),
297            left_type: L::type_name(),
298            right_type: R::type_name(),
299            composition_rules: SumCompositionRules::default(),
300        };
301
302        self.sum_types.push(sum_composition);
303        self
304    }
305
306    /// Add product type composition (Tuple/Record types)
307    #[must_use]
308    pub fn product_type<T>(mut self, types: Vec<T>) -> Self
309    where
310        T: CompositionType + Send + Sync + 'static,
311    {
312        let product_composition = ProductTypeComposition {
313            composition_id: uuid::Uuid::new_v4().to_string(),
314            component_types: types.iter().map(|t| T::type_name()).collect(),
315            composition_rules: ProductCompositionRules::default(),
316        };
317
318        self.product_types.push(product_composition);
319        self
320    }
321
322    /// Add pattern matching composition
323    pub fn pattern<P>(mut self, pattern_matcher: P) -> Self
324    where
325        P: PatternMatcher + Send + Sync + 'static,
326    {
327        self.pattern_matchers.push(Box::new(pattern_matcher));
328        self
329    }
330
331    /// Add algebraic operation
332    #[must_use]
333    pub fn operation(mut self, operation: AlgebraicOperation) -> Self {
334        self.algebraic_ops.push(operation);
335        self
336    }
337
338    /// Build algebraic composition
339    #[must_use]
340    pub fn build(self) -> AlgebraicComposition {
341        /// AlgebraicComposition
342        AlgebraicComposition {
343            composition_id: uuid::Uuid::new_v4().to_string(),
344            sum_types: self.sum_types,
345            product_types: self.product_types,
346            pattern_matchers: self.pattern_matchers,
347            algebraic_ops: self.algebraic_ops,
348        }
349    }
350}
351
352/// Higher-order composition abstractions for meta-composition
353///
354/// Provides higher-order abstractions for composing compositions, meta-level
355/// composition operations, and recursive composition patterns.
356#[derive(Debug)]
357pub struct HigherOrderComposer {
358    /// Meta-compositions
359    meta_compositions: Vec<MetaComposition>,
360    /// Composition combinators
361    combinators: Vec<Box<dyn CompositionCombinator>>,
362    /// Recursive composition patterns
363    recursive_patterns: Vec<RecursiveCompositionPattern>,
364    /// Higher-order transformations
365    higher_order_transforms: Vec<Box<dyn HigherOrderTransform>>,
366}
367
368impl HigherOrderComposer {
369    /// Create a new higher-order composer
370    #[must_use]
371    pub fn new() -> Self {
372        Self {
373            meta_compositions: Vec::new(),
374            combinators: Vec::new(),
375            recursive_patterns: Vec::new(),
376            higher_order_transforms: Vec::new(),
377        }
378    }
379
380    /// Compose compositions (meta-composition)
381    pub fn compose_compositions<C1, C2>(mut self, comp1: C1, comp2: C2) -> Self
382    where
383        C1: Composition + Send + Sync + 'static,
384        C2: Composition + Send + Sync + 'static,
385    {
386        let meta_composition = MetaComposition {
387            meta_id: uuid::Uuid::new_v4().to_string(),
388            compositions: vec![Box::new(comp1), Box::new(comp2)],
389            meta_rules: MetaCompositionRules::default(),
390        };
391
392        self.meta_compositions.push(meta_composition);
393        self
394    }
395
396    /// Add composition combinator
397    pub fn combinator<C>(mut self, combinator: C) -> Self
398    where
399        C: CompositionCombinator + Send + Sync + 'static,
400    {
401        self.combinators.push(Box::new(combinator));
402        self
403    }
404
405    /// Add recursive composition pattern
406    #[must_use]
407    pub fn recursive_pattern(mut self, pattern: RecursiveCompositionPattern) -> Self {
408        self.recursive_patterns.push(pattern);
409        self
410    }
411
412    /// Add higher-order transformation
413    pub fn transform<T>(mut self, transform: T) -> Self
414    where
415        T: HigherOrderTransform + Send + Sync + 'static,
416    {
417        self.higher_order_transforms.push(Box::new(transform));
418        self
419    }
420
421    /// Build higher-order composition
422    #[must_use]
423    pub fn build(self) -> HigherOrderComposition {
424        /// HigherOrderComposition
425        HigherOrderComposition {
426            composition_id: uuid::Uuid::new_v4().to_string(),
427            meta_compositions: self.meta_compositions,
428            combinators: self.combinators,
429            recursive_patterns: self.recursive_patterns,
430            higher_order_transforms: self.higher_order_transforms,
431        }
432    }
433}
434
435/// Trait for types that can be composed
436pub trait CompositionType {
437    /// Get the type name for composition validation
438    fn type_name() -> String;
439
440    /// Get type constraints
441    fn type_constraints() -> Vec<TypeConstraint>;
442
443    /// Check type compatibility
444    fn is_compatible_with(other: &str) -> bool;
445}
446
447/// Trait for typed transformers
448pub trait TypedTransformer<I, O>: Send + Sync
449where
450    I: CompositionType,
451    O: CompositionType,
452{
453    /// Transform input to output
454    fn transform(&self, input: I) -> SklResult<O>;
455
456    /// Get transformer metadata
457    fn metadata(&self) -> TransformerMetadata;
458
459    /// Validate transformation
460    fn validate(&self, input: &I) -> SklResult<()>;
461}
462
463/// Trait for type predicates
464pub trait TypePredicate<T>: Send + Sync {
465    /// Evaluate predicate on input
466    fn evaluate(&self, input: &T) -> bool;
467
468    /// Get predicate description
469    fn description(&self) -> String;
470}
471
472/// Trait for composition functions
473pub trait CompositionFunction: Send + Sync + std::fmt::Debug {
474    /// Apply the function
475    fn apply(&self, input: &PipelineData) -> SklResult<PipelineData>;
476
477    /// Get function signature
478    fn signature(&self) -> FunctionSignature;
479}
480
481/// Trait for functor pattern
482pub trait Functor<A, B>: Send + Sync {
483    /// Map function over the functor
484    fn fmap(&self, f: Box<dyn Fn(A) -> B + Send + Sync>) -> SklResult<B>;
485}
486
487/// Trait for monad pattern
488pub trait Monad<A, B>: Send + Sync {
489    /// Monadic return
490    fn return_value(value: A) -> Self;
491
492    /// Monadic bind
493    fn bind(&self, f: Box<dyn Fn(A) -> Self + Send + Sync>) -> SklResult<Self>
494    where
495        Self: Sized;
496}
497
498/// Trait for applicative functor
499pub trait Applicative<F, B>: Send + Sync {
500    /// Apply wrapped function to wrapped value
501    fn apply(&self, f: F) -> SklResult<B>;
502}
503
504/// Trait for monad transformers
505pub trait MonadTransformer: Send + Sync + std::fmt::Debug {
506    /// Transform the monad
507    fn transform(&self, monad: &dyn std::any::Any) -> SklResult<Box<dyn std::any::Any>>;
508}
509
510/// Trait for applicative functors
511pub trait ApplicativeFunctor: Send + Sync + std::fmt::Debug {
512    /// Apply the functor
513    fn apply_functor(&self, value: &dyn std::any::Any) -> SklResult<Box<dyn std::any::Any>>;
514}
515
516/// Trait for pattern matching
517pub trait PatternMatcher: Send + Sync + std::fmt::Debug {
518    /// Match pattern and execute corresponding action
519    fn match_pattern(&self, input: &PipelineData) -> SklResult<PatternMatchResult>;
520
521    /// Get pattern description
522    fn pattern_description(&self) -> String;
523}
524
525/// Trait for composition combinators
526pub trait CompositionCombinator: Send + Sync + std::fmt::Debug {
527    /// Combine compositions
528    fn combine(&self, compositions: Vec<Box<dyn Composition>>) -> SklResult<Box<dyn Composition>>;
529
530    /// Get combinator metadata
531    fn combinator_metadata(&self) -> CombinatorMetadata;
532}
533
534/// Trait for higher-order transformations
535pub trait HigherOrderTransform: Send + Sync + std::fmt::Debug {
536    /// Apply higher-order transformation
537    fn transform(&self, composition: Box<dyn Composition>) -> SklResult<Box<dyn Composition>>;
538
539    /// Get transformation metadata
540    fn transform_metadata(&self) -> TransformMetadata;
541}
542
543/// Trait for compositions
544pub trait Composition: Send + Sync + std::fmt::Debug {
545    /// Execute the composition
546    fn execute(&self, input: PipelineData) -> SklResult<PipelineData>;
547
548    /// Get composition metadata
549    fn composition_metadata(&self) -> CompositionMetadata;
550
551    /// Validate the composition
552    fn validate(&self) -> SklResult<()>;
553}
554
555/// Typed composition stage
556#[derive(Debug)]
557pub struct TypedCompositionStage {
558    /// Stage identifier
559    pub stage_id: String,
560    /// Input type
561    pub input_type: String,
562    /// Output type
563    pub output_type: String,
564    /// Transformer for this stage
565    pub transformer: Box<dyn std::any::Any + Send + Sync>,
566    /// Type constraints
567    pub type_constraints: Vec<TypeConstraint>,
568}
569
570/// Complete typed composition
571#[derive(Debug)]
572pub struct TypedComposition<I, O> {
573    /// Composition identifier
574    pub composition_id: String,
575    /// Composition stages
576    pub stages: Vec<TypedCompositionStage>,
577    /// Type constraints
578    pub type_constraints: TypeConstraints,
579    /// Composition metadata
580    pub metadata: CompositionMetadata,
581    /// Phantom type markers
582    pub _input_type: PhantomData<I>,
583    pub _output_type: PhantomData<O>,
584}
585
586/// Functional composition
587#[derive(Debug)]
588pub struct FunctionalComposition {
589    /// Composition identifier
590    pub composition_id: String,
591    /// Function composition chain
592    pub composition_chain: Vec<Box<dyn CompositionFunction>>,
593    /// Monad transformers
594    pub monad_transformers: Vec<Box<dyn MonadTransformer>>,
595    /// Applicative functors
596    pub applicative_functors: Vec<Box<dyn ApplicativeFunctor>>,
597    /// Category morphisms
598    pub morphisms: Vec<CategoryMorphism>,
599}
600
601/// Algebraic composition
602#[derive(Debug)]
603pub struct AlgebraicComposition {
604    /// Composition identifier
605    pub composition_id: String,
606    /// Sum type compositions
607    pub sum_types: Vec<SumTypeComposition>,
608    /// Product type compositions
609    pub product_types: Vec<ProductTypeComposition>,
610    /// Pattern matchers
611    pub pattern_matchers: Vec<Box<dyn PatternMatcher>>,
612    /// Algebraic operations
613    pub algebraic_ops: Vec<AlgebraicOperation>,
614}
615
616/// Higher-order composition
617#[derive(Debug)]
618pub struct HigherOrderComposition {
619    /// Composition identifier
620    pub composition_id: String,
621    /// Meta-compositions
622    pub meta_compositions: Vec<MetaComposition>,
623    /// Composition combinators
624    pub combinators: Vec<Box<dyn CompositionCombinator>>,
625    /// Recursive patterns
626    pub recursive_patterns: Vec<RecursiveCompositionPattern>,
627    /// Higher-order transformations
628    pub higher_order_transforms: Vec<Box<dyn HigherOrderTransform>>,
629}
630
631/// Type constraints for composition validation
632#[derive(Debug, Clone)]
633pub struct TypeConstraints {
634    /// Type compatibility rules
635    pub compatibility_rules: HashMap<String, Vec<String>>,
636    /// Type coercion rules
637    pub coercion_rules: HashMap<String, String>,
638    /// Custom type validators
639    pub custom_validators: Vec<String>,
640}
641
642impl TypeConstraints {
643    #[must_use]
644    pub fn new() -> Self {
645        Self {
646            compatibility_rules: HashMap::new(),
647            coercion_rules: HashMap::new(),
648            custom_validators: Vec::new(),
649        }
650    }
651
652    #[must_use]
653    pub fn has_coercion(&self, from_type: &str, to_type: &str) -> bool {
654        self.coercion_rules
655            .get(from_type)
656            .is_some_and(|target| target == to_type)
657    }
658}
659
660/// Type constraint specification
661#[derive(Debug, Clone)]
662pub struct TypeConstraint {
663    /// Constraint name
664    pub name: String,
665    /// Constraint type
666    pub constraint_type: ConstraintType,
667    /// Constraint parameters
668    pub parameters: HashMap<String, String>,
669}
670
671/// Constraint types
672#[derive(Debug, Clone)]
673pub enum ConstraintType {
674    /// Type equality constraint
675    Equality,
676    /// Type compatibility constraint
677    Compatibility,
678    /// Type coercion constraint
679    Coercion,
680    /// Custom constraint
681    Custom(String),
682}
683
684/// Parallel branch for type-safe composition
685pub struct ParallelBranch<I, O> {
686    /// Branch identifier
687    pub branch_id: String,
688    /// Branch transformer
689    pub transformer: Box<dyn TypedTransformer<I, O>>,
690    /// Branch weight
691    pub weight: f64,
692    /// Phantom type markers
693    pub _input_type: PhantomData<I>,
694    pub _output_type: PhantomData<O>,
695}
696
697impl<I, O> std::fmt::Debug for ParallelBranch<I, O> {
698    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
699        f.debug_struct("ParallelBranch")
700            .field("branch_id", &self.branch_id)
701            .field("transformer", &"<transformer>")
702            .field("weight", &self.weight)
703            .field("_input_type", &self._input_type)
704            .field("_output_type", &self._output_type)
705            .finish()
706    }
707}
708
709/// Sum type composition (Either/Union)
710#[derive(Debug, Clone)]
711pub struct SumTypeComposition {
712    /// Composition identifier
713    pub composition_id: String,
714    /// Left type
715    pub left_type: String,
716    /// Right type
717    pub right_type: String,
718    /// Composition rules
719    pub composition_rules: SumCompositionRules,
720}
721
722/// Product type composition (Tuple/Record)
723#[derive(Debug, Clone)]
724pub struct ProductTypeComposition {
725    /// Composition identifier
726    pub composition_id: String,
727    /// Component types
728    pub component_types: Vec<String>,
729    /// Composition rules
730    pub composition_rules: ProductCompositionRules,
731}
732
733/// Meta-composition for composing compositions
734#[derive(Debug)]
735pub struct MetaComposition {
736    /// Meta-composition identifier
737    pub meta_id: String,
738    /// Composed compositions
739    pub compositions: Vec<Box<dyn Composition>>,
740    /// Meta-composition rules
741    pub meta_rules: MetaCompositionRules,
742}
743
744/// Category theory morphism
745#[derive(Debug, Clone)]
746pub struct CategoryMorphism {
747    /// Morphism identifier
748    pub morphism_id: String,
749    /// Source category
750    pub source: String,
751    /// Target category
752    pub target: String,
753    /// Morphism properties
754    pub properties: MorphismProperties,
755}
756
757/// Algebraic operation
758#[derive(Debug, Clone)]
759pub struct AlgebraicOperation {
760    /// Operation identifier
761    pub operation_id: String,
762    /// Operation type
763    pub operation_type: AlgebraicOperationType,
764    /// Operation parameters
765    pub parameters: HashMap<String, serde_json::Value>,
766}
767
768/// Recursive composition pattern
769#[derive(Debug, Clone)]
770pub struct RecursiveCompositionPattern {
771    /// Pattern identifier
772    pub pattern_id: String,
773    /// Pattern type
774    pub pattern_type: RecursivePatternType,
775    /// Base case
776    pub base_case: String,
777    /// Recursive case
778    pub recursive_case: String,
779}
780
781/// Composition metadata
782#[derive(Debug, Clone)]
783pub struct CompositionMetadata {
784    /// Creation timestamp
785    pub created_at: Instant,
786    /// Composition name
787    pub name: Option<String>,
788    /// Composition description
789    pub description: Option<String>,
790    /// Custom metadata
791    pub custom_metadata: HashMap<String, String>,
792}
793
794impl CompositionMetadata {
795    #[must_use]
796    pub fn new() -> Self {
797        Self {
798            created_at: Instant::now(),
799            name: None,
800            description: None,
801            custom_metadata: HashMap::new(),
802        }
803    }
804}
805
806/// Transformer metadata
807#[derive(Debug, Clone)]
808pub struct TransformerMetadata {
809    /// Transformer name
810    pub name: String,
811    /// Input type
812    pub input_type: String,
813    /// Output type
814    pub output_type: String,
815    /// Transformer version
816    pub version: String,
817}
818
819/// Function signature
820#[derive(Debug, Clone)]
821pub struct FunctionSignature {
822    /// Function name
823    pub name: String,
824    /// Input types
825    pub input_types: Vec<String>,
826    /// Output type
827    pub output_type: String,
828    /// Side effects
829    pub side_effects: Vec<String>,
830}
831
832/// Pattern match result
833#[derive(Debug, Clone)]
834pub struct PatternMatchResult {
835    /// Whether pattern matched
836    pub matched: bool,
837    /// Extracted values
838    pub extracted_values: HashMap<String, serde_json::Value>,
839    /// Next action
840    pub next_action: String,
841}
842
843/// Combinator metadata
844#[derive(Debug, Clone)]
845pub struct CombinatorMetadata {
846    /// Combinator name
847    pub name: String,
848    /// Combinator type
849    pub combinator_type: String,
850    /// Associativity
851    pub associativity: Associativity,
852}
853
854/// Transform metadata
855#[derive(Debug, Clone)]
856pub struct TransformMetadata {
857    /// Transform name
858    pub name: String,
859    /// Transform type
860    pub transform_type: String,
861    /// Order of transformation
862    pub order: u32,
863}
864
865/// Sum composition rules
866#[derive(Debug, Clone)]
867pub struct SumCompositionRules {
868    /// Default branch
869    pub default_branch: SumBranch,
870    /// Branch selection strategy
871    pub selection_strategy: BranchSelectionStrategy,
872}
873
874impl Default for SumCompositionRules {
875    fn default() -> Self {
876        Self {
877            default_branch: SumBranch::Left,
878            selection_strategy: BranchSelectionStrategy::TypeBased,
879        }
880    }
881}
882
883/// Product composition rules
884#[derive(Debug, Clone)]
885pub struct ProductCompositionRules {
886    /// Composition strategy
887    pub composition_strategy: ProductCompositionStrategy,
888    /// Field access rules
889    pub field_access: FieldAccessRules,
890}
891
892impl Default for ProductCompositionRules {
893    fn default() -> Self {
894        Self {
895            composition_strategy: ProductCompositionStrategy::Parallel,
896            field_access: FieldAccessRules::ByIndex,
897        }
898    }
899}
900
901/// Meta-composition rules
902#[derive(Debug, Clone)]
903pub struct MetaCompositionRules {
904    /// Composition order
905    pub composition_order: CompositionOrder,
906    /// Error handling strategy
907    pub error_handling: MetaErrorHandling,
908}
909
910impl Default for MetaCompositionRules {
911    fn default() -> Self {
912        Self {
913            composition_order: CompositionOrder::Sequential,
914            error_handling: MetaErrorHandling::FailFast,
915        }
916    }
917}
918
919/// Morphism properties
920#[derive(Debug, Clone)]
921pub struct MorphismProperties {
922    /// Is identity morphism
923    pub is_identity: bool,
924    /// Is composable
925    pub is_composable: bool,
926    /// Morphism type
927    pub morphism_type: MorphismType,
928}
929
930/// Enumeration types for composition patterns
931#[derive(Debug, Clone)]
932pub enum SumBranch {
933    /// Left
934    Left,
935    /// Right
936    Right,
937}
938
939#[derive(Debug, Clone)]
940pub enum BranchSelectionStrategy {
941    /// TypeBased
942    TypeBased,
943    /// ValueBased
944    ValueBased,
945    /// Custom
946    Custom(String),
947}
948
949#[derive(Debug, Clone)]
950pub enum ProductCompositionStrategy {
951    /// Sequential
952    Sequential,
953    /// Parallel
954    Parallel,
955    /// Adaptive
956    Adaptive,
957}
958
959#[derive(Debug, Clone)]
960pub enum FieldAccessRules {
961    /// ByIndex
962    ByIndex,
963    /// ByName
964    ByName,
965    /// ByType
966    ByType,
967}
968
969#[derive(Debug, Clone)]
970pub enum CompositionOrder {
971    /// Sequential
972    Sequential,
973    /// Parallel
974    Parallel,
975    /// Dependency
976    Dependency,
977}
978
979#[derive(Debug, Clone)]
980pub enum MetaErrorHandling {
981    /// FailFast
982    FailFast,
983    /// Continue
984    Continue,
985    /// Retry
986    Retry,
987}
988
989#[derive(Debug, Clone)]
990pub enum AlgebraicOperationType {
991    /// Union
992    Union,
993    /// Intersection
994    Intersection,
995    /// Product
996    Product,
997    /// Quotient
998    Quotient,
999    /// Custom
1000    Custom(String),
1001}
1002
1003#[derive(Debug, Clone)]
1004pub enum RecursivePatternType {
1005    /// TailRecursion
1006    TailRecursion,
1007    /// TreeRecursion
1008    TreeRecursion,
1009    /// MutualRecursion
1010    MutualRecursion,
1011    /// Custom
1012    Custom(String),
1013}
1014
1015#[derive(Debug, Clone)]
1016pub enum MorphismType {
1017    /// Functor
1018    Functor,
1019    /// NaturalTransformation
1020    NaturalTransformation,
1021    /// Adjunction
1022    Adjunction,
1023    /// Custom
1024    Custom(String),
1025}
1026
1027#[derive(Debug, Clone)]
1028pub enum Associativity {
1029    /// Left
1030    Left,
1031    /// Right
1032    Right,
1033    None,
1034}
1035
1036/// Advanced composition errors
1037#[derive(Debug, Error)]
1038pub enum AdvancedCompositionError {
1039    #[error("Type mismatch: expected {expected}, got {actual}")]
1040    TypeMismatch { expected: String, actual: String },
1041
1042    #[error("Invalid composition: {0}")]
1043    InvalidComposition(String),
1044
1045    #[error("Pattern match failed: {0}")]
1046    PatternMatchFailed(String),
1047
1048    #[error("Algebraic operation failed: {0}")]
1049    AlgebraicOperationFailed(String),
1050
1051    #[error("Higher-order transformation failed: {0}")]
1052    HigherOrderTransformFailed(String),
1053}
1054
1055impl Default for TypeConstraints {
1056    fn default() -> Self {
1057        Self::new()
1058    }
1059}
1060
1061impl Default for CompositionMetadata {
1062    fn default() -> Self {
1063        Self::new()
1064    }
1065}
1066
1067impl Default for FunctionalComposer {
1068    fn default() -> Self {
1069        Self::new()
1070    }
1071}
1072
1073impl Default for AlgebraicComposer {
1074    fn default() -> Self {
1075        Self::new()
1076    }
1077}
1078
1079impl Default for HigherOrderComposer {
1080    fn default() -> Self {
1081        Self::new()
1082    }
1083}
1084
1085#[allow(non_snake_case)]
1086#[cfg(test)]
1087mod tests {
1088    use super::*;
1089    use std::time::Duration;
1090
1091    // Mock type for testing
1092    struct TestType;
1093
1094    impl CompositionType for TestType {
1095        fn type_name() -> String {
1096            "TestType".to_string()
1097        }
1098
1099        fn type_constraints() -> Vec<TypeConstraint> {
1100            Vec::new()
1101        }
1102
1103        fn is_compatible_with(_other: &str) -> bool {
1104            true
1105        }
1106    }
1107
1108    struct TestTransformer;
1109
1110    impl TypedTransformer<TestType, TestType> for TestTransformer {
1111        fn transform(&self, input: TestType) -> SklResult<TestType> {
1112            Ok(input)
1113        }
1114
1115        fn metadata(&self) -> TransformerMetadata {
1116            /// TransformerMetadata
1117            TransformerMetadata {
1118                name: "TestTransformer".to_string(),
1119                input_type: "TestType".to_string(),
1120                output_type: "TestType".to_string(),
1121                version: "1.0.0".to_string(),
1122            }
1123        }
1124
1125        fn validate(&self, _input: &TestType) -> SklResult<()> {
1126            Ok(())
1127        }
1128    }
1129
1130    #[test]
1131    fn test_type_constraints() {
1132        let mut constraints = TypeConstraints::new();
1133        constraints
1134            .coercion_rules
1135            .insert("String".to_string(), "Number".to_string());
1136
1137        assert!(constraints.has_coercion("String", "Number"));
1138        assert!(!constraints.has_coercion("Number", "String"));
1139    }
1140
1141    #[test]
1142    fn test_composition_metadata() {
1143        let metadata = CompositionMetadata::new();
1144        assert!(metadata.created_at.elapsed() < Duration::from_secs(1));
1145        assert!(metadata.name.is_none());
1146    }
1147
1148    #[test]
1149    fn test_functional_composer() {
1150        let composer = FunctionalComposer::new();
1151        let composition = composer.build();
1152
1153        assert!(!composition.composition_id.is_empty());
1154        assert_eq!(composition.composition_chain.len(), 0);
1155    }
1156
1157    #[test]
1158    fn test_algebraic_composer() {
1159        let composer = AlgebraicComposer::new().sum_type(TestType, TestType);
1160
1161        let composition = composer.build();
1162        assert!(!composition.composition_id.is_empty());
1163        assert_eq!(composition.sum_types.len(), 1);
1164    }
1165
1166    #[test]
1167    fn test_higher_order_composer() {
1168        let composer = HigherOrderComposer::new();
1169        let composition = composer.build();
1170
1171        assert!(!composition.composition_id.is_empty());
1172        assert_eq!(composition.meta_compositions.len(), 0);
1173    }
1174}