# Generalized Constraint Projection Method

**Repository Path**: will-captain/gcp

## Basic Information

- **Project Name**: Generalized Constraint Projection Method
- **Description**: 同样编程语言类型自动推导系统：
1. Outline AST 标准
2. 动态语言适配：Javascript，Python
3. 全量自动推导动态语言类型
- **Primary Language**: Java
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2025-03-28
- **Last Updated**: 2025-05-20

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Generalized Constraint Projection Method (GCP)
The longstanding conflict between type safety and development efficiency in dynamic programming languages has persistently constrained large-scale application development. Addressing three major pain points in mainstream type systems such as TypeScript: **redundant declarations, insufficient context sensitivity, and cumbersome generic type inference** . GPC proposes a progressive type inference method based on Outline Constraint Projection. The methodology comprises three core components:
- **Outline Generation Mechanism:** Establishes abstract type representations of code through structural analysis.
- **Structural Compatibility Validation (OEM)**: Formalizes verification for duck typing systems using object equivalence modeling.
- **Generalized Constraint Projection (GCP) Algorithm:** Achieves type convergence under multiple constraints through bidirectional constraint resolution.
  
This approach demonstrates effective type inference in complex scenarios such as dynamic object extension and higher-order function derivation. It provides both a novel theoretical framework and practical implementation pathways for static type assurance in dynamic languages, bridging the gap between flexibility and reliability without compromising developer productivity.
### 1. Build Type System via Outline (Structural Type Specification)
````
outline Animal = {age:Integer, weight:Float};//object outline expression
outline to_string = Number -> String; //function outline expression
outline Union = String&Number; //Poly outline expresion
````

### 2. verify "is" relationship via OEM (Outline Expression Match)
OEM use Duck Typing to verify "is" relationship
give τ_S$  and τ_T ，the "is" relationship will be ：
````math
τ_S≺τ_T⟺∀p∈Props(τ_T),∃p∈Props(τ_S)∧τ_S(p)≺τ_T(p)
````

````
outline Animal = {age:Integer, weight:Float};
outline Human = {age:Integer, weight:Float, name:String};
````
Human is Animal

### 3. infer the final type via GCP (Generalized Constraint Projection)
GCP via 4 constriants to build constraint chain：
C=⟨τ_e <:τ_d <:τ_h​ <:τ_f⟩ 

- τ_e (extend_to_be): Left-value constraint
- τ_d (declared_to_be): Declaration constraint
- τ_h (has_to_be): Right-value constraint
- τ_f (defined_to_be): Definition constraint

inferred type should be located in C=⟨τ_e <: **Projection** <:τ_d <:τ_h​ <:τ_f⟩

### Key Innovations:
- Enables precise type inference for dynamic language patterns while minimizing annotation overhead
- Formalizes structural equivalence checks while preserving runtime adaptability
- Solves intricate generic type relationships in higher-order abstractions

## summary
By reconciling the inherent flexibility of dynamic programming with rigorous static analysis, this methodology advances the state of type systems for JavaScript, Python, and similar languages, offering a viable solution for enterprise-scale application development.