From 210893ce090d251df1b75082035deb60a9b06be5 Mon Sep 17 00:00:00 2001 From: Vincent Ambo Date: Fri, 20 Dec 2019 21:46:59 +0000 Subject: chore(yants): Prepare for depot-merge Yants is being integrated at //depot/nix/yants --- .travis.yml | 4 - CODE_OF_CONDUCT.md | 20 --- CONTRIBUTING.md | 115 ------------ LICENSE | 202 --------------------- README.md | 86 --------- default.nix | 298 ------------------------------- nix/yants/.skip-subtree | 1 + nix/yants/README.md | 86 +++++++++ nix/yants/default.nix | 298 +++++++++++++++++++++++++++++++ nix/yants/screenshots/enums.png | Bin 0 -> 41305 bytes nix/yants/screenshots/functions.png | Bin 0 -> 32907 bytes nix/yants/screenshots/nested-structs.png | Bin 0 -> 70264 bytes nix/yants/screenshots/simple.png | Bin 0 -> 43010 bytes nix/yants/screenshots/structs.png | Bin 0 -> 69499 bytes nix/yants/tests.nix | 92 ++++++++++ screenshots/enums.png | Bin 41305 -> 0 bytes screenshots/functions.png | Bin 32907 -> 0 bytes screenshots/nested-structs.png | Bin 70264 -> 0 bytes screenshots/simple.png | Bin 43010 -> 0 bytes screenshots/structs.png | Bin 69499 -> 0 bytes tests.nix | 92 ---------- 21 files changed, 477 insertions(+), 817 deletions(-) delete mode 100644 .travis.yml delete mode 100644 CODE_OF_CONDUCT.md delete mode 100644 CONTRIBUTING.md delete mode 100644 LICENSE delete mode 100644 README.md delete mode 100644 default.nix create mode 100644 nix/yants/.skip-subtree create mode 100644 nix/yants/README.md create mode 100644 nix/yants/default.nix create mode 100644 nix/yants/screenshots/enums.png create mode 100644 nix/yants/screenshots/functions.png create mode 100644 nix/yants/screenshots/nested-structs.png create mode 100644 nix/yants/screenshots/simple.png create mode 100644 nix/yants/screenshots/structs.png create mode 100644 nix/yants/tests.nix delete mode 100644 screenshots/enums.png delete mode 100644 screenshots/functions.png delete mode 100644 screenshots/nested-structs.png delete mode 100644 screenshots/simple.png delete mode 100644 screenshots/structs.png delete mode 100644 tests.nix diff --git a/.travis.yml b/.travis.yml deleted file mode 100644 index f38ce14fe3ba..000000000000 --- a/.travis.yml +++ /dev/null @@ -1,4 +0,0 @@ -language: nix -nix: 2.2.2 -script: - - nix eval --raw '(import ./tests.nix)' --show-trace diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md deleted file mode 100644 index c4013ac13ebc..000000000000 --- a/CODE_OF_CONDUCT.md +++ /dev/null @@ -1,20 +0,0 @@ -A SERMON ON ETHICS AND LOVE -=========================== - -One day Mal-2 asked the messenger spirit Saint Gulik to approach the Goddess and request Her presence for some desperate advice. Shortly afterwards the radio came on by itself, and an ethereal female Voice said **YES?** - -"O! Eris! Blessed Mother of Man! Queen of Chaos! Daughter of Discord! Concubine of Confusion! O! Exquisite Lady, I beseech You to lift a heavy burden from my heart!" - -**WHAT BOTHERS YOU, MAL? YOU DON'T SOUND WELL.** - -"I am filled with fear and tormented with terrible visions of pain. Everywhere people are hurting one another, the planet is rampant with injustices, whole societies plunder groups of their own people, mothers imprison sons, children perish while brothers war. O, woe." - -**WHAT IS THE MATTER WITH THAT, IF IT IS WHAT YOU WANT TO DO?** - -"But nobody Wants it! Everybody hates it." - -**OH. WELL, THEN *STOP*.** - -At which moment She turned herself into an aspirin commercial and left The Polyfather stranded alone with his species. - -SINISTER DEXTER HAS A BROKEN SPIROMETER. diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md deleted file mode 100644 index fb5f8210ddb5..000000000000 --- a/CONTRIBUTING.md +++ /dev/null @@ -1,115 +0,0 @@ -Contribution Guidelines -======================= - - -**Table of Contents** - -- [Contribution Guidelines](#contribution-guidelines) - - [Before making a change](#before-making-a-change) - - [Commit messages](#commit-messages) - - [Commit content](#commit-content) - - [Code quality](#code-quality) - - [Builds & tests](#builds--tests) - - - -This is a loose set of "guidelines" for contributing to my projects. -Please note that I will not accept any pull requests that don't follow -these guidelines. - -Also consider the [code of conduct](CODE_OF_CONDUCT.md). No really, -you should. - -## Before making a change - -Before making a change, consider your motivation for making the -change. Documentation updates, bug fixes and the like are *always* -welcome. - -When adding a feature you should consider whether it is only useful -for your particular use-case or whether it is generally applicable for -other users of the project. - -When in doubt - just ask me! - -## Commit messages - -All commit messages should follow the style-guide used by the [Angular -project][]. This means for the most part that your commit message -should be structured like this: - -``` -type(scope): Subject line with at most 68 a character length - -Body of the commit message with an empty line between subject and -body. This text should explain what the change does and why it has -been made, *especially* if it introduces a new feature. - -Relevant issues should be mentioned if they exist. -``` - -Where `type` can be one of: - -* `feat`: A new feature has been introduced -* `fix`: An issue of some kind has been fixed -* `docs`: Documentation or comments have been updated -* `style`: Formatting changes only -* `refactor`: Hopefully self-explanatory! -* `test`: Added missing tests / fixed tests -* `chore`: Maintenance work - -And `scope` should refer to some kind of logical grouping inside of -the project. In smaller projects or when the scope is very large, it -can be omitted. - -Please take a look at the existing commit log for examples. - -## Commit content - -Multiple changes should be divided into multiple git commits whenever -possible. Common sense applies. - -The fix for a single-line whitespace issue is fine to include in a -different commit. Introducing a new feature and refactoring -(unrelated) code in the same commit is not fine. - -`git commit -a` is generally **taboo**. - -In my experience making "sane" commits becomes *significantly* easier -as developer tooling is improved. The interface to `git` that I -recommend is [magit][]. Even if you are not yet an Emacs user, it -makes sense to install Emacs just to be able to use magit - it is -really that good. - -For staging sane chunks on the command line with only git, consider -`git add -p`. - -## Code quality - -This one should go without saying - but please ensure that your code -quality does not fall below the rest of the project. This is of course -very subjective, but as an example if you place code that throws away -errors into a block in which errors are handled properly your change -will be rejected. - -In my experience there is a strong correlation between the visual -appearance of a code block and its quality. This is a simple way to -sanity-check your work while squinting and keeping some distance from -your screen ;-) - -## Builds & tests - -Most of my projects are built using [Nix][] to avoid "build pollution" -via the user's environment. If you have Nix installed and are -contributing to a project that has a `default.nix`, consider using -`nix-build` to verify that builds work correctly. - -If the project has tests, check that they still work before submitting -your change. - -Both of these will usually be covered by Travis CI. - - -[Angular project]: https://gist.github.com/stephenparish/9941e89d80e2bc58a153#format-of-the-commit-message -[magit]: https://magit.vc/ -[Nix]: https://nixos.org/nix/ diff --git a/LICENSE b/LICENSE deleted file mode 100644 index d64569567334..000000000000 --- a/LICENSE +++ /dev/null @@ -1,202 +0,0 @@ - - Apache License - Version 2.0, January 2004 - http://www.apache.org/licenses/ - - TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION - - 1. 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We also recommend that a - file or class name and description of purpose be included on the - same "printed page" as the copyright notice for easier - identification within third-party archives. - - Copyright [yyyy] [name of copyright owner] - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. diff --git a/README.md b/README.md deleted file mode 100644 index 54e3e4a6a4f2..000000000000 --- a/README.md +++ /dev/null @@ -1,86 +0,0 @@ -yants -===== - -[![Build Status](https://travis-ci.org/tazjin/yants.svg?branch=master)](https://travis-ci.org/tazjin/yants) - -This is a tiny type-checker for data in Nix, written in Nix. - -# Features - -* Checking of primitive types (`int`, `string` etc.) -* Checking polymorphic types (`option`, `list`, `either`) -* Defining & checking struct/record types -* Defining & matching enum types -* Defining & matching sum types -* Defining function signatures (including curried functions) -* Types are composable! `option string`! `list (either int (option float))`! -* Type errors also compose! - -Currently lacking: - -* Any kind of inference -* Convenient syntax for attribute-set function signatures - -## Primitives & simple polymorphism - -![simple](screenshots/simple.png) - -## Structs - -![structs](screenshots/structs.png) - -## Nested structs! - -![nested structs](screenshots/nested-structs.png) - -## Enums! - -![enums](screenshots/enums.png) - -## Functions! - -![functions](screenshots/functions.png) - -# Usage - -Yants can be imported from its `default.nix`. A single attribute (`lib`) can be -passed, which will otherwise be imported from ``. - -Examples for the most common import methods would be: - -1. Import into scope with `with`: - ```nix - with (import ./default.nix {}); - # ... Nix code that uses yants ... - ``` - -2. Import as a named variable: - ```nix - let yants = import ./default.nix {}; - in yants.string "foo" # or other uses ... - ```` - -3. Overlay into `pkgs.lib`: - ```nix - # wherever you import your package set (e.g. from ): - import { - overlays = [ - (self: super: { - lib = super.lib // { yants = import ./default.nix { inherit (super) lib; }; }; - }) - ]; - } - - # yants now lives at lib.yants, besides the other library functions! - ``` - -Please see my [Nix one-pager](https://github.com/tazjin/nix-1p) for more generic -information about the Nix language and what the above constructs mean. - -# Stability - -The current API of Yants is **not yet** considered stable, but it works fine and -should continue to do so even if used at an older version. - -Yants' tests use Nix versions above 2.2 - compatibility with older versions is -not guaranteed. diff --git a/default.nix b/default.nix deleted file mode 100644 index 2167b6e8b71f..000000000000 --- a/default.nix +++ /dev/null @@ -1,298 +0,0 @@ -# Copyright 2019 Google LLC -# SPDX-License-Identifier: Apache-2.0 -# -# Provides a "type-system" for Nix that provides various primitive & -# polymorphic types as well as the ability to define & check records. -# -# All types (should) compose as expected. - -{ lib ? (import {}).lib }: - -with builtins; let - prettyPrint = lib.generators.toPretty {}; - - # typedef' :: struct { - # name = string; - # checkType = function; (a -> result) - # checkToBool = option function; (result -> bool) - # toError = option function; (a -> result -> string) - # def = option any; - # match = option function; - # } -> type - # -> (a -> b) - # -> (b -> bool) - # -> (a -> b -> string) - # -> type - # - # This function creates an attribute set that acts as a type. - # - # It receives a type name, a function that is used to perform a - # check on an arbitrary value, a function that can translate the - # return of that check to a boolean that informs whether the value - # is type-conformant, and a function that can construct error - # messages from the check result. - # - # This function is the low-level primitive used to create types. For - # many cases the higher-level 'typedef' function is more appropriate. - typedef' = { name, checkType - , checkToBool ? (result: result.ok) - , toError ? (_: result: result.err) - , def ? null - , match ? null }: { - inherit name checkToBool toError; - - # check :: a -> bool - # - # This function is used to determine whether a given type is - # conformant. - check = value: checkToBool (checkType value); - - # checkType :: a -> struct { ok = bool; err = option string; } - # - # This function checks whether the passed value is type conformant - # and returns an optional type error string otherwise. - inherit checkType; - - # __functor :: a -> a - # - # This function checks whether the passed value is type conformant - # and throws an error if it is not. - # - # The name of this function is a special attribute in Nix that - # makes it possible to execute a type attribute set like a normal - # function. - __functor = self: value: - let result = self.checkType value; - in if checkToBool result then value - else throw (toError value result); - }; - - typeError = type: val: - "expected type '${type}', but value '${prettyPrint val}' is of type '${typeOf val}'"; - - # typedef :: string -> (a -> bool) -> type - # - # typedef is the simplified version of typedef' which uses a default - # error message constructor. - typedef = name: check: typedef' { - inherit name; - checkType = check; - checkToBool = r: r; - toError = value: _result: typeError name value; - }; - - checkEach = name: t: l: foldl' (acc: e: - let res = t.checkType e; - isT = t.checkToBool res; - in { - ok = acc.ok && isT; - err = if isT - then acc.err - else acc.err + "${prettyPrint e}: ${t.toError e res}\n"; - }) { ok = true; err = "expected type ${name}, but found:\n"; } l; -in lib.fix (self: { - # Primitive types - any = typedef "any" (_: true); - int = typedef "int" isInt; - bool = typedef "bool" isBool; - float = typedef "float" isFloat; - string = typedef "string" isString; - path = typedef "path" (x: typeOf x == "path"); - drv = typedef "derivation" (x: isAttrs x && x ? "type" && x.type == "derivation"); - function = typedef "function" (x: isFunction x || (isAttrs x && x ? "__functor" - && isFunction x.__functor)); - - # Type for types themselves. Useful when defining polymorphic types. - type = typedef "type" (x: - isAttrs x - && hasAttr "name" x && self.string.check x.name - && hasAttr "checkType" x && self.function.check x.checkType - && hasAttr "checkToBool" x && self.function.check x.checkToBool - && hasAttr "toError" x && self.function.check x.toError - ); - - # Polymorphic types - option = t: typedef' rec { - name = "option<${t.name}>"; - checkType = v: - let res = t.checkType v; - in { - ok = isNull v || (self.type t).checkToBool res; - err = "expected type ${name}, but value does not conform to '${t.name}': " - + t.toError v res; - }; - }; - - eitherN = tn: typedef "either<${concatStringsSep ", " (map (x: x.name) tn)}>" - (x: any (t: (self.type t).check x) tn); - - either = t1: t2: self.eitherN [ t1 t2 ]; - - list = t: typedef' rec { - name = "list<${t.name}>"; - - checkType = v: if isList v - then checkEach name (self.type t) v - else { - ok = false; - err = typeError name v; - }; - }; - - attrs = t: typedef' rec { - name = "attrs<${t.name}>"; - - checkType = v: if isAttrs v - then checkEach name (self.type t) (attrValues v) - else { - ok = false; - err = typeError name v; - }; - }; - - # Structs / record types - # - # Checks that all fields match their declared types, no optional - # fields are missing and no unexpected fields occur in the struct. - # - # Anonymous structs are supported (e.g. for nesting) by omitting the - # name. - # - # TODO: Support open records? - struct = - # Struct checking is more involved than the simpler types above. - # To make the actual type definition more readable, several - # helpers are defined below. - let - # checkField checks an individual field of the struct against - # its definition and creates a typecheck result. These results - # are aggregated during the actual checking. - checkField = def: name: value: let result = def.checkType value; in rec { - ok = def.checkToBool result; - err = if !ok && isNull value - then "missing required ${def.name} field '${name}'\n" - else "field '${name}': ${def.toError value result}\n"; - }; - - # checkExtraneous determines whether a (closed) struct contains - # any fields that are not part of the definition. - checkExtraneous = def: has: acc: - if (length has) == 0 then acc - else if (hasAttr (head has) def) - then checkExtraneous def (tail has) acc - else checkExtraneous def (tail has) { - ok = false; - err = acc.err + "unexpected struct field '${head has}'\n"; - }; - - # checkStruct combines all structure checks and creates one - # typecheck result from them - checkStruct = def: value: - let - init = { ok = true; err = ""; }; - extraneous = checkExtraneous def (attrNames value) init; - - checkedFields = map (n: - let v = if hasAttr n value then value."${n}" else null; - in checkField def."${n}" n v) (attrNames def); - - combined = foldl' (acc: res: { - ok = acc.ok && res.ok; - err = if !res.ok then acc.err + res.err else acc.err; - }) init checkedFields; - in { - ok = combined.ok && extraneous.ok; - err = combined.err + extraneous.err; - }; - - struct' = name: def: typedef' { - inherit name def; - checkType = value: if isAttrs value - then (checkStruct (self.attrs self.type def) value) - else { ok = false; err = typeError name value; }; - - toError = _: result: "expected '${name}'-struct, but found:\n" + result.err; - }; - in arg: if isString arg then (struct' arg) else (struct' "anon" arg); - - # Enums & pattern matching - enum = - let - plain = name: def: typedef' { - inherit name def; - - checkType = (x: isString x && elem x def); - checkToBool = x: x; - toError = value: _: "'${prettyPrint value} is not a member of enum ${name}"; - }; - enum' = name: def: lib.fix (e: (plain name def) // { - match = x: actions: deepSeq (map e (attrNames actions)) ( - let - actionKeys = attrNames actions; - missing = foldl' (m: k: if (elem k actionKeys) then m else m ++ [ k ]) [] def; - in if (length missing) > 0 - then throw "Missing match action for members: ${prettyPrint missing}" - else actions."${e x}"); - }); - in arg: if isString arg then (enum' arg) else (enum' "anon" arg); - - # Sum types - # - # The representation of a sum type is an attribute set with only one - # value, where the key of the value denotes the variant of the type. - sum = - let - plain = name: def: typedef' { - inherit name def; - checkType = (x: - let variant = elemAt (attrNames x) 0; - in if isAttrs x && length (attrNames x) == 1 && hasAttr variant def - then let t = def."${variant}"; - v = x."${variant}"; - res = t.checkType v; - in if t.checkToBool res - then { ok = true; } - else { - ok = false; - err = "while checking '${name}' variant '${variant}': " - + t.toError v res; - } - else { ok = false; err = typeError name x; } - ); - }; - sum' = name: def: lib.fix (s: (plain name def) // { - match = x: actions: - let variant = deepSeq (s x) (elemAt (attrNames x) 0); - actionKeys = attrNames actions; - defKeys = attrNames def; - missing = foldl' (m: k: if (elem k actionKeys) then m else m ++ [ k ]) [] defKeys; - in if (length missing) > 0 - then throw "Missing match action for variants: ${prettyPrint missing}" - else actions."${variant}" x."${variant}"; - }); - in arg: if isString arg then (sum' arg) else (sum' "anon" arg); - - # Typed function definitions - # - # These definitions wrap the supplied function in type-checking - # forms that are evaluated when the function is called. - # - # Note that typed functions themselves are not types and can not be - # used to check values for conformity. - defun = - let - mkFunc = sig: f: { - inherit sig; - __toString = self: foldl' (s: t: "${s} -> ${t.name}") - "λ :: ${(head self.sig).name}" (tail self.sig); - __functor = _: f; - }; - - defun' = sig: func: if length sig > 2 - then mkFunc sig (x: defun' (tail sig) (func ((head sig) x))) - else mkFunc sig (x: ((head (tail sig)) (func ((head sig) x)))); - - in sig: func: if length sig < 2 - then (throw "Signature must at least have two types (a -> b)") - else defun' sig func; -}) diff --git a/nix/yants/.skip-subtree b/nix/yants/.skip-subtree new file mode 100644 index 000000000000..51a8e01d4e29 --- /dev/null +++ b/nix/yants/.skip-subtree @@ -0,0 +1 @@ +Yants subtree contains no further derivations. diff --git a/nix/yants/README.md b/nix/yants/README.md new file mode 100644 index 000000000000..54e3e4a6a4f2 --- /dev/null +++ b/nix/yants/README.md @@ -0,0 +1,86 @@ +yants +===== + +[![Build Status](https://travis-ci.org/tazjin/yants.svg?branch=master)](https://travis-ci.org/tazjin/yants) + +This is a tiny type-checker for data in Nix, written in Nix. + +# Features + +* Checking of primitive types (`int`, `string` etc.) +* Checking polymorphic types (`option`, `list`, `either`) +* Defining & checking struct/record types +* Defining & matching enum types +* Defining & matching sum types +* Defining function signatures (including curried functions) +* Types are composable! `option string`! `list (either int (option float))`! +* Type errors also compose! + +Currently lacking: + +* Any kind of inference +* Convenient syntax for attribute-set function signatures + +## Primitives & simple polymorphism + +![simple](screenshots/simple.png) + +## Structs + +![structs](screenshots/structs.png) + +## Nested structs! + +![nested structs](screenshots/nested-structs.png) + +## Enums! + +![enums](screenshots/enums.png) + +## Functions! + +![functions](screenshots/functions.png) + +# Usage + +Yants can be imported from its `default.nix`. A single attribute (`lib`) can be +passed, which will otherwise be imported from ``. + +Examples for the most common import methods would be: + +1. Import into scope with `with`: + ```nix + with (import ./default.nix {}); + # ... Nix code that uses yants ... + ``` + +2. Import as a named variable: + ```nix + let yants = import ./default.nix {}; + in yants.string "foo" # or other uses ... + ```` + +3. Overlay into `pkgs.lib`: + ```nix + # wherever you import your package set (e.g. from ): + import { + overlays = [ + (self: super: { + lib = super.lib // { yants = import ./default.nix { inherit (super) lib; }; }; + }) + ]; + } + + # yants now lives at lib.yants, besides the other library functions! + ``` + +Please see my [Nix one-pager](https://github.com/tazjin/nix-1p) for more generic +information about the Nix language and what the above constructs mean. + +# Stability + +The current API of Yants is **not yet** considered stable, but it works fine and +should continue to do so even if used at an older version. + +Yants' tests use Nix versions above 2.2 - compatibility with older versions is +not guaranteed. diff --git a/nix/yants/default.nix b/nix/yants/default.nix new file mode 100644 index 000000000000..2167b6e8b71f --- /dev/null +++ b/nix/yants/default.nix @@ -0,0 +1,298 @@ +# Copyright 2019 Google LLC +# SPDX-License-Identifier: Apache-2.0 +# +# Provides a "type-system" for Nix that provides various primitive & +# polymorphic types as well as the ability to define & check records. +# +# All types (should) compose as expected. + +{ lib ? (import {}).lib }: + +with builtins; let + prettyPrint = lib.generators.toPretty {}; + + # typedef' :: struct { + # name = string; + # checkType = function; (a -> result) + # checkToBool = option function; (result -> bool) + # toError = option function; (a -> result -> string) + # def = option any; + # match = option function; + # } -> type + # -> (a -> b) + # -> (b -> bool) + # -> (a -> b -> string) + # -> type + # + # This function creates an attribute set that acts as a type. + # + # It receives a type name, a function that is used to perform a + # check on an arbitrary value, a function that can translate the + # return of that check to a boolean that informs whether the value + # is type-conformant, and a function that can construct error + # messages from the check result. + # + # This function is the low-level primitive used to create types. For + # many cases the higher-level 'typedef' function is more appropriate. + typedef' = { name, checkType + , checkToBool ? (result: result.ok) + , toError ? (_: result: result.err) + , def ? null + , match ? null }: { + inherit name checkToBool toError; + + # check :: a -> bool + # + # This function is used to determine whether a given type is + # conformant. + check = value: checkToBool (checkType value); + + # checkType :: a -> struct { ok = bool; err = option string; } + # + # This function checks whether the passed value is type conformant + # and returns an optional type error string otherwise. + inherit checkType; + + # __functor :: a -> a + # + # This function checks whether the passed value is type conformant + # and throws an error if it is not. + # + # The name of this function is a special attribute in Nix that + # makes it possible to execute a type attribute set like a normal + # function. + __functor = self: value: + let result = self.checkType value; + in if checkToBool result then value + else throw (toError value result); + }; + + typeError = type: val: + "expected type '${type}', but value '${prettyPrint val}' is of type '${typeOf val}'"; + + # typedef :: string -> (a -> bool) -> type + # + # typedef is the simplified version of typedef' which uses a default + # error message constructor. + typedef = name: check: typedef' { + inherit name; + checkType = check; + checkToBool = r: r; + toError = value: _result: typeError name value; + }; + + checkEach = name: t: l: foldl' (acc: e: + let res = t.checkType e; + isT = t.checkToBool res; + in { + ok = acc.ok && isT; + err = if isT + then acc.err + else acc.err + "${prettyPrint e}: ${t.toError e res}\n"; + }) { ok = true; err = "expected type ${name}, but found:\n"; } l; +in lib.fix (self: { + # Primitive types + any = typedef "any" (_: true); + int = typedef "int" isInt; + bool = typedef "bool" isBool; + float = typedef "float" isFloat; + string = typedef "string" isString; + path = typedef "path" (x: typeOf x == "path"); + drv = typedef "derivation" (x: isAttrs x && x ? "type" && x.type == "derivation"); + function = typedef "function" (x: isFunction x || (isAttrs x && x ? "__functor" + && isFunction x.__functor)); + + # Type for types themselves. Useful when defining polymorphic types. + type = typedef "type" (x: + isAttrs x + && hasAttr "name" x && self.string.check x.name + && hasAttr "checkType" x && self.function.check x.checkType + && hasAttr "checkToBool" x && self.function.check x.checkToBool + && hasAttr "toError" x && self.function.check x.toError + ); + + # Polymorphic types + option = t: typedef' rec { + name = "option<${t.name}>"; + checkType = v: + let res = t.checkType v; + in { + ok = isNull v || (self.type t).checkToBool res; + err = "expected type ${name}, but value does not conform to '${t.name}': " + + t.toError v res; + }; + }; + + eitherN = tn: typedef "either<${concatStringsSep ", " (map (x: x.name) tn)}>" + (x: any (t: (self.type t).check x) tn); + + either = t1: t2: self.eitherN [ t1 t2 ]; + + list = t: typedef' rec { + name = "list<${t.name}>"; + + checkType = v: if isList v + then checkEach name (self.type t) v + else { + ok = false; + err = typeError name v; + }; + }; + + attrs = t: typedef' rec { + name = "attrs<${t.name}>"; + + checkType = v: if isAttrs v + then checkEach name (self.type t) (attrValues v) + else { + ok = false; + err = typeError name v; + }; + }; + + # Structs / record types + # + # Checks that all fields match their declared types, no optional + # fields are missing and no unexpected fields occur in the struct. + # + # Anonymous structs are supported (e.g. for nesting) by omitting the + # name. + # + # TODO: Support open records? + struct = + # Struct checking is more involved than the simpler types above. + # To make the actual type definition more readable, several + # helpers are defined below. + let + # checkField checks an individual field of the struct against + # its definition and creates a typecheck result. These results + # are aggregated during the actual checking. + checkField = def: name: value: let result = def.checkType value; in rec { + ok = def.checkToBool result; + err = if !ok && isNull value + then "missing required ${def.name} field '${name}'\n" + else "field '${name}': ${def.toError value result}\n"; + }; + + # checkExtraneous determines whether a (closed) struct contains + # any fields that are not part of the definition. + checkExtraneous = def: has: acc: + if (length has) == 0 then acc + else if (hasAttr (head has) def) + then checkExtraneous def (tail has) acc + else checkExtraneous def (tail has) { + ok = false; + err = acc.err + "unexpected struct field '${head has}'\n"; + }; + + # checkStruct combines all structure checks and creates one + # typecheck result from them + checkStruct = def: value: + let + init = { ok = true; err = ""; }; + extraneous = checkExtraneous def (attrNames value) init; + + checkedFields = map (n: + let v = if hasAttr n value then value."${n}" else null; + in checkField def."${n}" n v) (attrNames def); + + combined = foldl' (acc: res: { + ok = acc.ok && res.ok; + err = if !res.ok then acc.err + res.err else acc.err; + }) init checkedFields; + in { + ok = combined.ok && extraneous.ok; + err = combined.err + extraneous.err; + }; + + struct' = name: def: typedef' { + inherit name def; + checkType = value: if isAttrs value + then (checkStruct (self.attrs self.type def) value) + else { ok = false; err = typeError name value; }; + + toError = _: result: "expected '${name}'-struct, but found:\n" + result.err; + }; + in arg: if isString arg then (struct' arg) else (struct' "anon" arg); + + # Enums & pattern matching + enum = + let + plain = name: def: typedef' { + inherit name def; + + checkType = (x: isString x && elem x def); + checkToBool = x: x; + toError = value: _: "'${prettyPrint value} is not a member of enum ${name}"; + }; + enum' = name: def: lib.fix (e: (plain name def) // { + match = x: actions: deepSeq (map e (attrNames actions)) ( + let + actionKeys = attrNames actions; + missing = foldl' (m: k: if (elem k actionKeys) then m else m ++ [ k ]) [] def; + in if (length missing) > 0 + then throw "Missing match action for members: ${prettyPrint missing}" + else actions."${e x}"); + }); + in arg: if isString arg then (enum' arg) else (enum' "anon" arg); + + # Sum types + # + # The representation of a sum type is an attribute set with only one + # value, where the key of the value denotes the variant of the type. + sum = + let + plain = name: def: typedef' { + inherit name def; + checkType = (x: + let variant = elemAt (attrNames x) 0; + in if isAttrs x && length (attrNames x) == 1 && hasAttr variant def + then let t = def."${variant}"; + v = x."${variant}"; + res = t.checkType v; + in if t.checkToBool res + then { ok = true; } + else { + ok = false; + err = "while checking '${name}' variant '${variant}': " + + t.toError v res; + } + else { ok = false; err = typeError name x; } + ); + }; + sum' = name: def: lib.fix (s: (plain name def) // { + match = x: actions: + let variant = deepSeq (s x) (elemAt (attrNames x) 0); + actionKeys = attrNames actions; + defKeys = attrNames def; + missing = foldl' (m: k: if (elem k actionKeys) then m else m ++ [ k ]) [] defKeys; + in if (length missing) > 0 + then throw "Missing match action for variants: ${prettyPrint missing}" + else actions."${variant}" x."${variant}"; + }); + in arg: if isString arg then (sum' arg) else (sum' "anon" arg); + + # Typed function definitions + # + # These definitions wrap the supplied function in type-checking + # forms that are evaluated when the function is called. + # + # Note that typed functions themselves are not types and can not be + # used to check values for conformity. + defun = + let + mkFunc = sig: f: { + inherit sig; + __toString = self: foldl' (s: t: "${s} -> ${t.name}") + "λ :: ${(head self.sig).name}" (tail self.sig); + __functor = _: f; + }; + + defun' = sig: func: if length sig > 2 + then mkFunc sig (x: defun' (tail sig) (func ((head sig) x))) + else mkFunc sig (x: ((head (tail sig)) (func ((head sig) x)))); + + in sig: func: if length sig < 2 + then (throw "Signature must at least have two types (a -> b)") + else defun' sig func; +}) diff --git a/nix/yants/screenshots/enums.png b/nix/yants/screenshots/enums.png new file mode 100644 index 000000000000..71673e7ab63c Binary files /dev/null and b/nix/yants/screenshots/enums.png differ diff --git a/nix/yants/screenshots/functions.png b/nix/yants/screenshots/functions.png new file mode 100644 index 000000000000..30ed50f8327b Binary files /dev/null and b/nix/yants/screenshots/functions.png differ diff --git a/nix/yants/screenshots/nested-structs.png b/nix/yants/screenshots/nested-structs.png new file mode 100644 index 000000000000..6b03ed65ceb7 Binary files /dev/null and b/nix/yants/screenshots/nested-structs.png differ diff --git a/nix/yants/screenshots/simple.png b/nix/yants/screenshots/simple.png new file mode 100644 index 000000000000..05a302cc6b9d Binary files /dev/null and b/nix/yants/screenshots/simple.png differ diff --git a/nix/yants/screenshots/structs.png b/nix/yants/screenshots/structs.png new file mode 100644 index 000000000000..fcbcf6415fad Binary files /dev/null and b/nix/yants/screenshots/structs.png differ diff --git a/nix/yants/tests.nix b/nix/yants/tests.nix new file mode 100644 index 000000000000..6863ced066f8 --- /dev/null +++ b/nix/yants/tests.nix @@ -0,0 +1,92 @@ +with builtins; +with (import ./default.nix {}); + +# Note: Derivations are not included in the tests below as they cause +# issues with deepSeq. + +deepSeq rec { + # Test that all primitive types match + primitives = [ + (int 15) + (bool false) + (float 13.37) + (string "Hello!") + (function (x: x * 2)) + (path /nix) + ]; + + # Test that polymorphic types work as intended + poly = [ + (option int null) + (list string [ "foo" "bar" ]) + (either int float 42) + ]; + + # Test that structures work as planned. + person = struct "person" { + name = string; + age = int; + + contact = option (struct { + email = string; + phone = option string; + }); + }; + + testPerson = person { + name = "Brynhjulf"; + age = 42; + contact.email = "brynhjulf@yants.nix"; + }; + + # Test enum definitions & matching + colour = enum "colour" [ "red" "blue" "green" ]; + testMatch = colour.match "red" { + red = "It is in fact red!"; + blue = throw "It should not be blue!"; + green = throw "It should not be green!"; + }; + + # Test sum type definitions + creature = sum "creature" { + human = struct { + name = string; + age = option int; + }; + + pet = enum "pet" [ "dog" "lizard" "cat" ]; + }; + + testSum = creature { + human = { + name = "Brynhjulf"; + age = 42; + }; + }; + + testSumMatch = creature.match testSum { + human = v: "It's a human named ${v.name}"; + pet = v: throw "It's not supposed to be a pet!"; + }; + + # Test curried function definitions + func = defun [ string int string ] + (name: age: "${name} is ${toString age} years old"); + + testFunc = func "Brynhjulf" 42; + + # Test that all types are types. + testTypes = map type [ + any bool drv float int string path + + (attrs int) + (eitherN [ int string bool ]) + (either int string) + (enum [ "foo" "bar" ]) + (list string) + (option int) + (option (list string)) + (struct { a = int; b = option string; }) + (sum { a = int; b = option string; }) + ]; +} "All tests passed!\n" diff --git a/screenshots/enums.png b/screenshots/enums.png deleted file mode 100644 index 71673e7ab63c..000000000000 Binary files a/screenshots/enums.png and /dev/null differ diff --git a/screenshots/functions.png b/screenshots/functions.png deleted file mode 100644 index 30ed50f8327b..000000000000 Binary files a/screenshots/functions.png and /dev/null differ diff --git a/screenshots/nested-structs.png b/screenshots/nested-structs.png deleted file mode 100644 index 6b03ed65ceb7..000000000000 Binary files a/screenshots/nested-structs.png and /dev/null differ diff --git a/screenshots/simple.png b/screenshots/simple.png deleted file mode 100644 index 05a302cc6b9d..000000000000 Binary files a/screenshots/simple.png and /dev/null differ diff --git a/screenshots/structs.png b/screenshots/structs.png deleted file mode 100644 index fcbcf6415fad..000000000000 Binary files a/screenshots/structs.png and /dev/null differ diff --git a/tests.nix b/tests.nix deleted file mode 100644 index 6863ced066f8..000000000000 --- a/tests.nix +++ /dev/null @@ -1,92 +0,0 @@ -with builtins; -with (import ./default.nix {}); - -# Note: Derivations are not included in the tests below as they cause -# issues with deepSeq. - -deepSeq rec { - # Test that all primitive types match - primitives = [ - (int 15) - (bool false) - (float 13.37) - (string "Hello!") - (function (x: x * 2)) - (path /nix) - ]; - - # Test that polymorphic types work as intended - poly = [ - (option int null) - (list string [ "foo" "bar" ]) - (either int float 42) - ]; - - # Test that structures work as planned. - person = struct "person" { - name = string; - age = int; - - contact = option (struct { - email = string; - phone = option string; - }); - }; - - testPerson = person { - name = "Brynhjulf"; - age = 42; - contact.email = "brynhjulf@yants.nix"; - }; - - # Test enum definitions & matching - colour = enum "colour" [ "red" "blue" "green" ]; - testMatch = colour.match "red" { - red = "It is in fact red!"; - blue = throw "It should not be blue!"; - green = throw "It should not be green!"; - }; - - # Test sum type definitions - creature = sum "creature" { - human = struct { - name = string; - age = option int; - }; - - pet = enum "pet" [ "dog" "lizard" "cat" ]; - }; - - testSum = creature { - human = { - name = "Brynhjulf"; - age = 42; - }; - }; - - testSumMatch = creature.match testSum { - human = v: "It's a human named ${v.name}"; - pet = v: throw "It's not supposed to be a pet!"; - }; - - # Test curried function definitions - func = defun [ string int string ] - (name: age: "${name} is ${toString age} years old"); - - testFunc = func "Brynhjulf" 42; - - # Test that all types are types. - testTypes = map type [ - any bool drv float int string path - - (attrs int) - (eitherN [ int string bool ]) - (either int string) - (enum [ "foo" "bar" ]) - (list string) - (option int) - (option (list string)) - (struct { a = int; b = option string; }) - (sum { a = int; b = option string; }) - ]; -} "All tests passed!\n" -- cgit 1.4.1