Python API index

Every stable name Python exports, and its extension seams.

Package: earthsci-ast 0.6.0

Documentation extracted with griffe 2.3.2.

Capability profiles: core, classification, simulation, runtime I/O.

Extension-tier names are on the Python extension page .

Stable names

Python	Canonical	Kind	Summary
`add_continuous_event`	`add_continuous_event`	function	Add a continuous event to a model.
`add_continuous_event_to_model`	`add_continuous_event`	function	Deprecated alias for `add_continuous_event`.
`add_coupling`	`add_coupling`	function	Add a coupling entry to an ESM file.
`add_coupling_to_file`	`add_coupling`	function	Deprecated alias for `add_coupling`.
`add_discrete_event`	`add_discrete_event`	function	Add a discrete event to a model.
`add_discrete_event_to_model`	`add_discrete_event`	function	Deprecated alias for `add_discrete_event`.
`add_equation`	`add_equation`	function	Add an equation to a model.
`add_equation_to_model`	`add_equation`	function	Deprecated alias for `add_equation`.
`add_reaction`	`add_reaction`	function	Add a reaction to a reaction system.
`add_reaction_to_system`	`add_reaction`	function	Deprecated alias for `add_reaction`.
`add_species`	`add_species`	function	Add a species to a reaction system.
`add_species_to_system`	`add_species`	function	Deprecated alias for `add_species`.
`add_variable`	`add_variable`	function	Add a variable to a model.
`add_variable_to_model`	`add_variable`	function	Deprecated alias for `add_variable`.
`AffectEquation`	`affect_equation`	type	Equation that affects a variable (assignment-like).
`algebraic_unknowns`	`algebraic_unknowns`	function	Unknowns constrained only implicitly (`HHSO4 ~ Ksp`), sorted.
`apply_unit_conversion`	`apply_unit_conversion`	function	Apply `conversion` to `values`.
`area_tolerance_ok`	`area_tolerance_ok`	function	Combined rel+abs area-agreement gate with a sliver floor (B.5 / §5.8.2).
`brownian_parameters`	`brownian_parameters`	function	Parameters whose `update.kind` is `"wiener"` — the SDE noise sources (esm-spec §6.3.1), sorted.
`build_reference_graph`	`build_reference_graph`	function	Resolve the reference edges of one `model` dict into a graph.
`CadenceError`	`cadence_error`	error	A cadence-partition contract violation in a model or producer output.
`callbacks`	`callbacks`	function	The EsmProblem’s callback set (esm-libraries-spec §2.5.4).
`CallbackSet`	`callback_set`	type	An ordered, immutable set of callbacks, declared on a `EsmProblem`.
`can_migrate`	`can_migrate`	function	True when `migrate` would succeed for this version pair.
`canonical_index_set_json`	`canonical_index_set_json`	function	Canonical byte form of an index set (`CONFORMANCE_SPEC.md` §5.5.3): the `distinct` rows, each tuple serialised as a JSON array, in §5.5.1 sorted order, as compact UTF-8 JSON.
`CircularReferenceError`	`circular_reference_error`	error	Exception raised when circular subsystem references are detected.
`Compiler`	`compiler`	type	The type a caller’s `compiler` keyword takes.
`CompilerReport`	`compiler_report`	type	Per rule, the tier it landed on and what declined on the way.
`component_exists`	`component_exists`	function	True when `component_id` names a model or reaction system of `file`.
`component_graph`	`component_graph`	function	Build the component/coupling graph of `file`.
`ComponentNode`	`component_node`	type	A model or reaction system in the component graph.
`ConflictingDerivativeError`	`conflicting_derivative_error`	error	Two systems define non-additive equations for the same dependent variable.
`constant_parameters`	`constant_parameters`	function	Parameters with neither a `distribution` nor an `update` — plain constants (esm-spec §6.3.1), sorted.
`contains`	`contains`	function	Check if an expression contains a specific variable.
`ContinuousEvent`	`continuous_event`	type	An event that occurs when a condition becomes true during continuous evolution.
`Contribution`	`contribution`	type	One summand of a flattened equation’s right-hand side, with its authors.
`convert_units`	`convert_units`	function	Convenience function to convert units.
`CoupleMultiplicativeNoTendencyError`	`couple_multiplicative_no_tendency_error`	error	A `multiplicative` connector transform targets something with no tendency.
`CouplingEdge`	`coupling_edge`	type	A coupling relationship between two components.
`CouplingEntry`	`coupling_entry`	type	One entry of a document’s `coupling` list (esm-spec §10): any of the coupling dataclasses, told apart by their `coupling_type` field (`CouplingType`), which is the wire `type`…
`CouplingImport`	`coupling_import`	type	Coupling entry that imports a coupling-library file (esm-spec §10.10).
`CyclicPromotionError`	`cyclic_promotion_error`	error	Promotion rules form a cycle (A→B→…→A).
`DataSource`	`data_source`	type	A named external data source reduced to pure I/O: it locates, reads, decodes, slices and filters bytes on disk (esm-spec §8).
`DataSourceBinding`	`data_source_binding`	type	Binds a parameter to ONE variable of a `data_sources` entry (esm-spec §8.5).
`DataSourceDeterminism`	`data_source_determinism`	type	Reproducibility contract a source advertises to bindings (esm-spec §8.9.2).
`DataSourceKind`	`data_source_kind`	type	Structural kind of an external data source.
`DataSourceLocation`	`data_source_location`	type	File discovery configuration for a data source.
`DataSourceTemporal`	`data_source_temporal`	type	Temporal coverage and record layout for a data source.
`declared_system_kind`	`declared_system_kind`	function	The model’s explicit `system_kind` field, or None when absent.
`default_forcing_set`	`default_forcing_set`	function	The Problem’s forcing as a forcing set.
`DependencyEdge`	`dependency_edge`	type	A dependency between two variables.
`derive_odes`	`derive_odes`	function	Derive ODEs from a reaction system using mass action kinetics.
`desugar_pushdown`	`desugar_pushdown`	function	Recognise the projection-pushdown pattern in `esm`’s named model and, when it matches, return a NEW document with the four constructs desugared in (a `kind:"derived"` index set,…
`DimensionPromotionError`	`dimension_promotion_error`	error	A variable or equation cannot be promoted given the available Interfaces.
`discrete_parameters`	`discrete_parameters`	function	Parameters carrying any update OTHER than `wiener` — piecewise-constant between refreshes (esm-spec §6.3.1), sorted.
`DiscreteEvent`	`discrete_event`	type	An event that occurs at discrete time points.
`DiscreteEventTrigger`	`discrete_event_trigger`	type	Trigger condition for a discrete event.
`distinct`	`distinct`	function	Set semantics over `rows`: sort by the §5.5.1 total order, then drop
`Distribution`	`distribution`	type	A parameter’s value drawn from a probability distribution (esm-spec §5.4 / §6.3).
`Domain`	`domain`	type	Comprehensive computational domain specification.
`DomainExtentMismatchError`	`domain_extent_mismatch_error`	error	Two domains coupled via `identity` have incompatible spatial extents.
`DomainUnitMismatchError`	`domain_unit_mismatch_error`	error	An Interface coupling requires a unit conversion that was not declared.
`EarthSciAstError`	`earth_sci_ast_error`	error	Root of the earthsci_ast exception hierarchy.
`EdgeKind`	`edge_kind`	type	The three kinds of reference edge (RFC §6.1 “Propagation”).
`effective_system_kind`	`effective_system_kind`	function	The kind a caller choosing a solver should act on: the declared `system_kind` field when the document states one, otherwise the §6.3.1 derivation.
`emit_document`	`emit_document`	function	Produce the reference-preserving, self-contained emitted document (esm-spec §9.6.4 rule 5, RFC out-of-line-expression-templates §7.5) from a source document (a fixture, or an…
`emit_esm_string`	`emit_esm_string`	function	Canonical byte serialization of an emitted document (esm-spec §9.6.4 rule 5): 2-space indent, object keys sorted lexicographically EXCEPT the entries of an `expression_templates`…
`EnsembleProblem`	`ensemble_problem`	type	A `EsmProblem` plus a per-trajectory rewrite (esm-libraries-spec §2.5.8).
`EnumLoweringError`	`enum_lowering_error`	error	Raised when enum lowering (esm-spec §9.3) fails.
`Equation`	`equation`	type	Mathematical equation with left and right hand sides.
`ERROR_CODES`	`error_codes`	constant	Every diagnostic code this binding can emit, keyed by its SCREAMING_SNAKE name: `ERROR_CODES.UNDEFINED_VARIABLE == "undefined_variable"`.
`esm_problem`	`esm_problem`	function	Build a document into a runnable `EsmProblem` (esm-libraries-spec §2.5.2).
`EsmFile`	`esm_file`	type	Root container for an ESM format file.
`EsmProblem`	`esm_problem`	type	A document, built and ready to run (esm-libraries-spec §2.5.2).
`evaluate`	`evaluate`	function	Evaluate a scalar AST expression against a dict of float variable bindings.
`Expand`	`expand`	function	Public alias for `expand_document` using the spec’s spelling (esm-spec §9.6.4 rule 2).
`expand_coupling_imports`	`expand_coupling_imports`	function	Expand every `coupling_import` entry in `esm_file.coupling` into concrete (typed) coupling edges, splicing them in the position of the import entry (esm-spec §10.10.3).
`expand_document`	`expand_document`	function	Fully expand every surviving `apply_expression_template` reference in a document `loaded` by `lower_expression_templates` (Option B), producing the Option-A image: every…
`Expr`	`expr`	type	An expression (esm-spec §4): a numeric literal (`int` or `float`), a variable or parameter reference (`str`), or an operator node (`ExprNode`) whose `args` are themselves…
`expression_graph`	`expression_graph`	function	Build the variable-dependency graph of `target`.
`ExpressionParseError`	`expression_parse_error`	error	Raised when an expression string cannot be parsed.
`ExpressionTemplateError`	`expression_template_error`	error	Raised when expression-template expansion fails.
`ExprNode`	`expr_node`	type	A node in an expression tree.
`extract`	`extract`	function	Extract a single component into a standalone ESM file.
`extract_component_from_file`	`extract`	function	Deprecated alias for `extract`.
`flatten`	`flatten`	function	Flatten a coupled multi-system EsmFile per spec §4.7.5.
`flatten_template_registries`	`flatten_template_registries`	function	The flatten-time template-registry merge (esm-spec §9.6.4 rule 7, §10.7; esm-libraries-spec §4.7.5 step 4).
`FlattenedEquation`	`flattened_equation`	type	An equation in the flattened system, with namespaced Expr trees.
`FlattenedSystem`	`flattened_system`	type	The result of flattening an EsmFile per spec §4.7.5.
`FlattenedVariable`	`flattened_variable`	type	A single variable in the flattened system.
`FlattenError`	`flatten_error`	error	Base class for errors raised during flatten().
`FlattenMetadata`	`flatten_metadata`	type	Provenance metadata for a FlattenedSystem.
`FloatKeyError`	`float_key_error`	error	Raised when a relational key contains a floating-point component.
`forcing_set`	`forcing_set`	function	An epoch-stamped forcing set for `prog`.
`free_parameters`	`free_parameters`	function	Extract free parameters from an expression.
`free_variables`	`free_variables`	function	Extract all free variables from an expression.
`FunctionalUpdate`	`functional_update`	type	A registered handler computing a parameter’s new value when its update fires (esm-spec §5.4).
`FunctionTable`	`function_table`	type	A sampled function table referenced by table_lookup AST ops (esm-spec §9.5, v0.4.0).
`FunctionTableAxis`	`function_table_axis`	type	A single named axis inside a FunctionTable (esm-spec §9.5).
`GeometryError`	`geometry_error`	error	A polygon-clip / area evaluation failed (bad operand, degenerate input).
`Graph`	`graph`	type	A directed graph with node/edge lists and adjacency lookups (§4.8).
`GraphEdge`	`graph_edge`	type	One directed edge: node keys plus the edge payload.
`group_aggregate`	`group_aggregate`	function	Group-by + semiring aggregate (rule 5).
`halo`	`halo`	function	The halo report of `op` along `dec`.
`init`	`init`	function	Build a stepping `Integrator` over `prob` (esm-libraries-spec §2.5.6).
`Integrator`	`integrator`	type	A stepping integrator over a `EsmProblem` (esm-libraries-spec §2.5.6).
`intersect_polygon`	`intersect_polygon`	function	Clip two lon-lat polygon rings; return the overlap ring (RFC §8.1).
`is_coupling_library_doc`	`is_coupling_library_doc`	function	True when `raw` has the coupling-library-file FORM (top-level `coupling_roles`, esm-spec §10.9).
`is_ode_state`	`is_ode_state`	function	Membership test for `ode_states` — the replacement for every `variable.type == "state"` branch.
`lanes`	`lanes`	function	`op` over a run-time list of cells or columns.
`LIBRARY_VERSION`	`library_version`	constant	This package’s OWN version – the cross-binding spelling of `__version__`.
`load_document`	`load_document`	function	Parse an ESM document that is ALREADY a Python `dict` — the same document a `.esm` file holds, just already `json.load`ed.
`load_path`	`load_path`	function	Read and parse an ESM document from a filesystem path.
`load_string`	`load_string`	function	Parse an ESM document from JSON TEXT.
`LoaderField`	`loader_field`	type	A data-fed PARAMETER lowered to a flattened array input (esm-spec §8.5).
`lower_enums`	`lower_enums`	function	Return `file` with every `enum` op replaced by a `const` integer per the file’s `enums` block (esm-spec §9.3).
`lower_enums_mut`	`lower_enums_mut`	function	In-place twin of `lower_enums`: lower every `enum` op in `file` itself, and return it (API_SPEC.md §8 item 15).
`lower_expression_templates`	`lower_expression_templates`	function	Run the load-time rewrite fixpoint (esm-spec §9.6.3) over `file`, Option B (reference-preserving, esm-spec §9.6.4).
`materialize_value_invention`	`materialize_value_invention`	function	Run the build-time value-invention engine over a raw model document.
`MAX_TEMPLATE_EXPANSION_DEPTH`	`max_template_expansion_depth`	constant	Maximum template-body reference-chain depth (counted in TEMPLATES along the longest chain, so a 33-template chain is rejected and a 32-template chain is accepted) before a file…
`merge`	`merge`	function	Merge two ESM files.
`merge_esm_files`	`merge`	function	Deprecated alias for `merge`.
`Metadata`	`metadata`	type	Metadata about the model or dataset.
`migrate`	`migrate`	function	Migrate `file` to `target_version`.
`MigrationError`	`migration_error`	error	Raised when an ESM document cannot be migrated to the requested version.
`Model`	`model`	type	A mathematical model containing variables and equations.
`ModelVariable`	`model_variable`	type	A variable in a mathematical model — either an `unknown` the solver solves for, or a `parameter` supplied to it.
`observed_definitions`	`observed_definitions`	function	Map each observed unknown to its DEFINING equation’s RHS.
`observed_field`	`observed_field`	function	Evaluate/read the state-free observed `name` at BUILD time through the EsmProblem’s own graph — the const-geometry hoist already materialized it; this resolves the name against…
`observed_unknowns`	`observed_unknowns`	function	Unknowns defined by a bare-variable LHS (`y ~ f(…)`) — eliminable, materializable (esm-spec §6.3.1), sorted.
`ode_states`	`ode_states`	function	Unknowns appearing under `D(·, t)` on some equation LHS (esm-spec §6.3.1), sorted.
`Operator`	`operator`	type	A registered runtime operator (e.g., dry deposition, wet scavenging).
`OperatorComposeAmbiguousBareNameError`	`operator_compose_ambiguous_bare_name_error`	error	A bare-name match unified two STATES and the document did not say which survives.
`OperatorComposeNoMergeError`	`operator_compose_no_merge_error`	error	An `operator_compose` entry merged NOTHING (esm-libraries-spec §4.7.1 step 5).
`OperatorComposeRequireMatchError`	`operator_compose_require_match_error`	error	An `operator_compose` entry declared `require_match` and did not match.
`Parameter`	`parameter`	type	A parameter for reaction systems.
`ParameterUpdate`	`parameter_update`	type	One rule declaring WHEN a parameter refreshes and WHAT from (esm-spec §5.4).
`parse_equation`	`parse_equation`	function	Parse `lhs = rhs` into an `Equation`.
`parse_expression`	`parse_expression`	function	Parse a single expression string into an AST expression — the inverse of `to_ascii`.
`parse_unit_conversion`	`parse_unit_conversion`	function	Parse a loader variable’s RAW `unit_conversion` (esm-spec §8.5).
`Partition`	`partition`	type	The result of the cadence-partition pass over one model.
`polygon_area`	`polygon_area`	function	Reference (unsigned) area of an overlap ring under `manifold`.
`product_matrix`	`product_matrix`	function	Compute the product stoichiometric matrix.
`rank`	`rank`	function	Dense integer renumbering (rule 3): assign IDs by position in the sorted `distinct` sequence.
`Ranking`	`ranking`	type	Result of `rank`.
`Reaction`	`reaction`	type	A chemical reaction.
`ReactionSystem`	`reaction_system`	type	A system of chemical reactions.
`Reference`	`reference`	type	Bibliographic reference.
`ReferenceEdge`	`reference_edge`	type	A directed `source → target` edge: source references/depends on target.
`ReferenceGraph`	`reference_graph`	type	The resolved reference DAG for one model — the partition pass’s input.
`ReferenceResolutionError`	`reference_resolution_error`	error	A reference could not be resolved, or the reference graph has a cycle.
`ReferenceVertex`	`reference_vertex`	type	A vertex in the reference graph, addressed by a kind-namespaced `key`.
`reject_expression_templates_pre_v04`	`reject_expression_templates_pre_v04`	function	Reject template constructs in files declaring esm < 0.4.0.
`reject_solver_external_pre_v13`	`reject_solver_external_pre_v13`	function	Reject `solver.external` in a file declaring esm < 1.3.0.
`reject_solver_pre_v11`	`reject_solver_pre_v11`	function	Reject a top-level `solver` block in a file declaring esm < 1.1.0.
`reject_solver_time_span_pre_v13`	`reject_solver_time_span_pre_v13`	function	Reject `solver.time_span` in a file declaring esm < 1.3.0.
`reject_template_imports_pre_v08`	`reject_template_imports_pre_v08`	function	Reject the §9.7 constructs in files declaring esm < 0.8.0.
`remake`	`remake`	function	A NEW EsmProblem with the named substitutions applied, everything else shared.
`remove_coupling`	`remove_coupling`	function	Remove a coupling entry from an ESM file.
`remove_coupling_from_file`	`remove_coupling`	function	Deprecated alias for `remove_coupling`.
`remove_equation`	`remove_equation`	function	Remove an equation from a model by index.
`remove_equation_from_model`	`remove_equation`	function	Deprecated alias for `remove_equation`.
`remove_event`	`remove_event`	function	Remove an event from a model.
`remove_event_from_model`	`remove_event`	function	Deprecated alias for `remove_event`.
`remove_reaction`	`remove_reaction`	function	Remove a reaction from a reaction system.
`remove_reaction_from_system`	`remove_reaction`	function	Deprecated alias for `remove_reaction`.
`remove_species`	`remove_species`	function	Remove a species from a reaction system.
`remove_species_from_system`	`remove_species`	function	Deprecated alias for `remove_species`.
`remove_variable`	`remove_variable`	function	Remove a variable from a model.
`remove_variable_from_model`	`remove_variable`	function	Deprecated alias for `remove_variable`.
`rename_variable`	`rename_variable`	function	Rename a variable in a model.
`rename_variable_in_model`	`rename_variable`	function	Deprecated alias for `rename_variable`.
`resolve_references`	`resolve_references`	function	Resolve reference edges for every model in `document`.
`resolve_subsystem_refs`	`resolve_subsystem_refs`	function	Resolve all subsystem references in an ESM file.
`resolve_template_machinery`	`resolve_template_machinery`	function	Resolve every esm-spec §9.7 construct of the ROOT document `raw` (relative import refs resolve against `base_path`): imports recursively with per-edge instantiation, `index_sets`…
`resolve_time_span`	`resolve_time_span`	function	The interval a run should cover, most-specific first (esm-spec §2.2.7).
`resolve_tolerances`	`resolve_tolerances`	function	Resolve integration tolerances most-specific first (esm-spec §2.2.2).
`restrict`	`restrict`	function	`op` restricted to one tile.
`ReturnCode`	`return_code`	type	The SciML `ReturnCode` vocabulary (API_SPEC §4, esm-libraries-spec §2.5.3), which is how a run reports its outcome in every simulating binding.
`rhs_program`	`rhs_program`	function	The Problem’s right-hand side as a program value.
`sampled_parameters`	`sampled_parameters`	function	Parameters with a `distribution` and no `update` — drawn once at setup (esm-spec §6.3.1), sorted.
`SCHEMA_VERSION`	`schema_version`	constant	The `.esm` FORMAT version this library implements — NOT the version of the library itself, which is `earthsci_ast.LIBRARY_VERSION`.
`SchemaValidationError`	`schema_validation_error`	error	Exception raised when schema validation fails.
`select`	`select`	function	One operator’s program, by provenance.
`simplify`	`simplify`	function	Simplify an expression by performing constant folding and basic algebraic simplifications.
`skolem`	`skolem`	function	Canonical-tuple Skolem key (rule 4).
`skolem_edge`	`skolem_edge`	function	Canonical key for an undirected pair (a symmetric relation): `(min(a, b), max(a, b))`.
`SliceOutOfDomainError`	`slice_out_of_domain_error`	error	A `slice` mapping reaches outside the source variable’s domain.
`Solution`	`solution`	type	What `earthsci_ast.problem.solve` returns.
`solve`	`solve`	function	Run `prob` to completion and return its `Solution`.
`Solver`	`solver`	type	Document-scoped, OPTIONAL solver hints (esm-spec §2.2).
`solver_external_location`	`solver_external_location`	function	Where the document’s `solver.external` points (esm-spec §2.2.6).
`SolverTimeSpan`	`solver_time_span`	type	`solver.time_span`: the interval a document is meant to be simulated over.
`Species`	`species`	type	A chemical species in a reaction system.
`step`	`step`	function	Advance `integrator` one accepted step — the spec’s `step!`.
`stoichiometric_matrix`	`stoichiometric_matrix`	function	Compute the net stoichiometric matrix for a reaction system.
`substitute`	`substitute`	function	Recursively substitute variables in an expression with their bindings.
`substitute_in_model`	`substitute_in_model`	function	Apply substitutions to all expressions in a model.
`substitute_in_reaction_system`	`substitute_in_reaction_system`	function	Apply substitutions to all expressions in a reaction system.
`substrate_matrix`	`substrate_matrix`	function	Compute the substrate (reactant) stoichiometric matrix.
`SubsystemRefError`	`subsystem_ref_error`	error	Exception raised when a subsystem reference cannot be resolved.
`supported_migration_targets`	`supported_migration_targets`	function	The schema versions `from_version` can migrate to.
`system_kind`	`system_kind`	function	Derive the model’s MTK system kind (esm-spec §6.3.1).
`TemporalDomain`	`temporal_domain`	type	Temporal domain specification.
`TermOrigin`	`term_origin`	type	Who authored one contribution to a flattened equation (esm-libraries-spec §4.7.5, “Per-term provenance”).
`to_ascii`	`to_ascii`	function	Format target as plain ASCII mathematical notation.
`to_dot`	`to_dot`	function	Render `graph` as Graphviz DOT.
`to_json`	`to_json`	function	Serialize an ESM file to a JSON string.
`to_json_compact`	`to_json_compact`	function	`to_json` with no indentation — the single-line wire form.
`to_json_graph`	`to_json_graph`	function	Render `graph` as the JSON adjacency list of esm-libraries-spec §4.8.3.
`to_julia_code`	`to_julia_code`	function	Generate a self-contained Julia script from an ESM file.
`to_latex`	`to_latex`	function	Format target as LaTeX mathematical notation.
`to_mermaid`	`to_mermaid`	function	Render `graph` as a Mermaid flowchart for Markdown embedding.
`to_unicode`	`to_unicode`	function	Format target as Unicode mathematical notation with chemical subscripts.
`UNIT_FINDING_ANALYSIS`	`unit_finding_analysis`	constant	The checker could not DETERMINE a dimension – a symbolic exponent, an operator with no dimensional rule, an unknown variable, a missing pint.
`UNIT_FINDING_DIMENSIONAL_MISMATCH`	`unit_finding_dimensional_mismatch`	constant	A PROVABLE inconsistency: metres added to kilograms, an equation whose sides cannot agree.
`UNIT_FINDING_DIMENSIONLESS_LITERAL`	`unit_finding_dimensionless_literal`	constant	A check the CURRENT neutral-literal rule skips or passes fails once a bare numeric literal is read as dimensionless (esm-spec §4.8.6).
`UNIT_FINDING_UNPARSEABLE`	`unit_finding_unparseable`	constant	A declared unit string that denotes no real unit.
`UnitConversionError`	`unit_conversion_error`	error	Raised when unit_conversion cannot be applied.
`UnitFinding`	`unit_finding`	type	One coded dimensional-analysis finding.
`UnitWarning`	`unit_warning`	type	A single dimensional-analysis finding.
`unknowns`	`unknowns`	function	Every variable declared `type: "unknown"`, sorted.
`UnmappedDomainError`	`unmapped_domain_error`	error	A coupling references a variable whose domain has no mapping rule.
`UnsupportedMappingError`	`unsupported_mapping_error`	error	A dimension-promotion mapping is not supported by this implementation tier.
`validate`	`validate`	function	Validate a parsed ESM document against structural and unit requirements.
`validate_path`	`validate_path`	function	Validate the ESM document stored at `path` (API_SPEC.md §8 item 13).
`validate_text`	`validate_text`	function	Validate an ESM document held as JSON text (API_SPEC.md §8 item 13).
`validate_units`	`validate_units`	function	Convenience function to validate units of an ESM structure.
`ValidationError`	`validation_error`	type	Represents a single validation error.
`ValidationResult`	`validation_result`	type	Represents the result of validation.
`ValueInventionError`	`value_invention_error`	error	A value-invention build-time materialisation error.
`ValueInventionResult`	`value_invention_result`	type	Result of `materialize_value_invention`.
`VariableNode`	`variable_node`	type	A variable, parameter or species in the expression graph.
`VertexKind`	`vertex_kind`	type	The three kinds of vertex in the reference graph.
`write_path`	`write_path`	function	Write an ESM file to `path` as JSON.