Crate fel_core 

FEL parser, evaluator, and dependency analysis with base-10 decimal arithmetic.

Uses rust_decimal for base-10 arithmetic per spec S3.4.1 (minimum 18 significant digits).

Docs

• Human overview: crate README.md (architecture, pipeline, module map).
• API reference: cargo doc -p fel-core --no-deps --open.
• Markdown API export: docs/rustdoc-md/API.md (see crate README).

Re-exports

pub use ast::Expr;

pub use context_json::formspec_environment_from_json_map;

pub use convert::fel_to_json;

pub use convert::field_map_from_json_str;

pub use convert::json_object_to_field_map;

pub use convert::json_to_fel;

pub use dependencies::Dependencies;

pub use dependencies::dependencies_to_json_value;

pub use dependencies::dependencies_to_json_value_styled;

pub use dependencies::extract_dependencies;

pub use environment::FormspecEnvironment;

pub use environment::MipState;

pub use environment::RepeatContext;

pub use error::Diagnostic;

pub use error::FelError;

pub use error::Severity;

pub use error::reject_undefined_functions;

pub use error::undefined_function_names_from_diagnostics;

pub use evaluator::Environment;

pub use evaluator::EvalResult;

pub use evaluator::Evaluator;

pub use evaluator::MapEnvironment;

pub use evaluator::evaluate;

pub use extensions::BuiltinFunctionCatalogEntry;

pub use extensions::ExtensionError;

pub use extensions::ExtensionRegistry;

pub use extensions::builtin_function_catalog;

pub use extensions::builtin_function_catalog_json_value;

pub use parser::parse;

pub use prepare_host::prepare_fel_expression_for_host;

pub use prepare_host::prepare_fel_expression_owned;

pub use prepare_host::prepare_fel_host_options_from_json_map;

pub use prepare_host::PrepareFelHostInput;

pub use prepare_host::PrepareFelHostOptionsOwned;

pub use printer::print_expr;

pub use types::FelDate;

pub use types::FelMoney;

pub use types::FelValue;

pub use types::parse_date_literal;

pub use types::parse_datetime_literal;

pub use lexer::is_valid_fel_identifier;

pub use lexer::sanitize_fel_identifier;

pub use wire_style::JsonWireStyle;

Modules

ast

FEL abstract syntax tree node definitions and operators.

context_json

Build FormspecEnvironment from JSON-shaped evaluation context.

convert

Canonical conversion between serde_json::Value and FelValue.

dependencies

Static dependency extraction — field refs, context refs, and MIP dependencies.

environment

FEL evaluation environment with field resolution, repeats, MIP state, and instances.

error

FEL error types and diagnostic messages.

evaluator

FEL tree-walking evaluator with base-10 decimal arithmetic and null propagation.

extensions

FEL extension function registry with null propagation and conflict detection.

lexer

FEL hand-rolled lexer — tokenization with spans and decimal numbers.

parser

FEL hand-rolled recursive descent parser with operator precedence.

prepare_host

FEL source normalization before host evaluation (parity with TS normalizeExpressionForWasmEvaluation).

printer

FEL AST to string serializer for expression rewriting and debugging.

types

FEL runtime value types with base-10 decimal arithmetic.

wire_style

Host JSON key convention shared across FEL dependency wire and Formspec FFI surfaces.

Structs

Decimal

Decimal represents a 128 bit representation of a fixed-precision decimal number. The finite set of values of type Decimal are of the form m / 10^e, where m is an integer such that -2⁹⁶ < m < 2⁹⁶, and e is an integer between 0 and 28 inclusive.

PositionedToken

One lexeme from tokenize for host bindings and tooling (stable type names + source span).

Functions

eval_with_fields

Parse and evaluate a FEL expression with a flat field map.

fel_diagnostics_to_json_value

Evaluation diagnostics as JSON objects (message, severity wire string).

tokenize

Tokenize FEL source into PositionedTokens (lexical analysis only; no parse).

tokenize_to_json_value

FEL lexer tokens as JSON (camelCase keys) for host bindings.