Stdlib

Eta Standard Library Reference

Reference documentation for the modules under stdlib/std/. Each page lists the module’s exported symbols with short descriptions and call shapes. For tutorials and longer examples see the Language Guide.

Quick-reference tables — per-module API tables with navigation breadcrumbs are also available in the Guide stdlib index.

Conventions

• Most non-pure modules expose a colon-prefixed namespace (csv:read-row, log:info, clp:domain, …). The colon is part of the symbol name; it is not a Scheme operator.
• A few modules also export bare aliases (for example std.atom exports both atom:deref and deref).
• Names ending in ! mutate state. Names ending in ? return a boolean.
• Functions documented with . opts accept a trailing key/value list.
• Modules wrap runtime built-ins prefixed % (for example %csv-*, %regex-*). Those built-ins are implementation detail and are not documented here.
• Some modules require optional build flags:
  • std.net, std.supervisor need -DETA_BUILD_NNG=ON.
  • std.torch needs -DETA_BUILD_TORCH=ON.

Modules

Core / language

• std.core - Combinators, accessors, platform predicate.
• std.collections - Higher-order list and vector ops.
• std.math - Math constants and numeric helpers.
• std.io - I/O conveniences and port redirection.

Data structures

• std.atom - Atomic mutable references with CAS.
• std.hashmap - Hash-map helpers.
• std.hashset - Hash-set helpers.
• std.fact_table - Columnar fact tables.

Logic and constraints

• std.logic - miniKanren-style goal combinators.
• std.freeze - Attributed-variable combinators.
• std.clp - CLP(Z) and CLP(FD) over integers.
• std.clpb - CLP(B) Boolean propagation.
• std.clpr - CLP(R) over real intervals with LP/QP.
• std.db - Datalog-style relations on fact tables.

Causal inference

• std.causal - DAG operations and back-door identification.
• std.causal.adjustment - GAC, front-door, IV.
• std.causal.admg - ADMG helpers and latent projection.
• std.causal.identify - ID/IDC algorithms.
• std.causal.counterfactual - Twin networks, ETT.
• std.causal.mediation - NDE, NIE, CDE.
• std.causal.estimate - ATE, IPW, AIPW, TMLE.
• std.causal.cate - Meta-learners (S/T/X/R/DR).
• std.causal.crossfit - Cross-fitting and DML.
• std.causal.forest - Causal forests via DR scores.
• std.causal.learn - Structure learning (PC, NOTEARS).
• std.causal.policy - Uplift and policy values.
• std.causal.render - DOT, Mermaid, LaTeX rendering.
• std.causal.transport - Transportability.

Statistics and machine learning

• std.stats - Descriptive stats, t-tests, OLS.
• std.aad - Reverse-mode AD helpers.
• std.torch - libtorch tensors, NN, optimizers.
• std.ml.tree - Regression CART.
• std.ml.forest - Bagged regression forests.

Systems and I/O

• std.fs - Filesystem and path helpers.
• std.os - Environment, argv, working directory.
• std.process - Subprocess management.
• std.time - Clocks, sleep, ISO-8601 formatting.
• std.regex - Regular expressions.
• std.csv - CSV reader/writer.
• std.json - JSON read/write.
• std.log - Structured logging.
• std.args - Command-line argument parsing.

Concurrency and networking

• std.net - Networking patterns over NNG.
• std.supervisor - Actor supervision strategies.

Tooling

• std.test - Unit tests with TAP/JUnit reporters.
• std.jupyter - Notebook MIME display markers.
• std.prof - Runtime profiling sessions and reports.