Dynspec.jl

A concise, type-stable Julia package for reading, interpreting, and analyzing dynamic economic model specifications, replicating and extending the dynspec engine of dyno.

Core Principles

1. Unified AbstractModelBlock Architecture: Models are represented by ModelBlock <: AbstractModelBlock, holding a calibrated type-stable Context, an iterable collection of Equations, metadata, and the complete preserved grammar parse tree (Tree).
2. Behavioral Interface: A model block is defined by its ability to evaluate residuals and analytical jacobian / derivatives, rather than merely being a vector of equations.
3. Preserved Parse Tree: The full AST is preserved on both the block and individual equations. This avoids re-lexing or re-parsing when calibrating parameters, running variant sweeps, or targeting alternate symbolic backends.
4. Decoupled Equation Filtering (filter_by): Residual and derivative evaluations accept filter_by to filter equations by block tags (:transition, :arbitrage, etc.) or custom predicates.
5. Exact Analytical Differentiation via ForwardDiff: Computes exact machine-precision derivatives using ForwardDiff.Dual numbers without slow symbolic engines or custom derivative dictionaries.
6. Clean, Predictable Context: Model contexts hold typed dictionaries (constants, steady_states, processes, values), providing unambiguous, explicit access (context.constants[:α]) and avoiding namespace collisions.

Quick Installation

using Pkg
Pkg.add(url="https://github.com/EconForge/dynspec.jl")

See the Function & Option Guide for a comprehensive demonstration of all package functions and options.