Name the language Ivo.

README.md

@@ -1,33 +1,59 @@
-# Lambda Calculus
+# The Ivo Programming Language
-This is a simple programming language derived from lambda calculus,
+Ivo (IPA: /aɪvoʊ/) is a programming language intended
-using the Hindley-Milner type system, plus `letrec` and `callcc`.
+as a tool for its author to explore interesting programming language features.
 
-## Usage
+Ivo is currently in a very early stage of development
-Run the program using `stack run` (or run the tests with `stack test`).
+and most likely is not of any practical or academic interest;
+however, that may change in the future.
+This README serves to document the language as it currently stands,
+not what the language one day hopes to be.
 
-Type in your expression at the prompt: `>> `.
+## Using the Ivo interpreter
-Yourexpression will be evaluated to normal form using the call-by-value evaluation strategy and then printed.
+You may run the Ivo interpreter using `stack run`;
+the interpreter does not take any arguments.
+
+Type in your command, definition, or expression at the prompt: `>> `.
+Expressions will be typechecked, evaluated using call-by-value, and then printed.
 
 Exit the prompt with `Ctrl-d` (or equivalent).
 
-## Commands
+### Interpreter commands
-Instead of entering an expression in the REPL, you may enter a command.
 These commands are available:
 
-* `:load <filename>`: Execute a program in the interpreter, importing all definitions.
 * `:clear`: Clear all of your variable definitions.
+
+* `:load <filename>`:
+
+  Execute a file containing Ivo definitions and expressions in the interpreter.
+  Variables already defined in the interpreter will be defined in the file;
+  variables defined by the file will be defined in the interpreter.
+
+  The filename may contain spaces, but trailing whitespace will be trimmed.
+
 * `:check <on/off> <always/decls/off>`:
-  * If the first argument is `off`, then expressions will be evaluated even if they do not typecheck.
+
-  * If the second argument is `always`, inferred types will always be printed.
+  * If the first argument is `on`,
-    If it is `decls`, then only declarations will have their inferred types printed.
+    then expressions will only be evaluated and definitions will only be added
-    Otherwise, the type of expressions is never printed.
+    only if typechecking succeeds.
+
+  * If the second argument is `always`, then inferred types will always be printed;
+    if it is `decls`, then only the inferred types of declarations will be printed;
+    otherwise, the type of expressions are never printed.'
+
   * The default values are `on` `decls`.
+
 * `:trace <off/local/global>`:
-  * If the argument is `local`, intermediate expressions will be printed as the evaluator evaluates them.
+
-  * If the argument is `global`, the *entire* expression will be printed each evaluator step.
+  * If the argument is `local`, intermediate expressions will be printed
+    as they are evaluated;
+
+  * If the argument is `global`, the *entire* expression will be printed
+    with each evaluation step.
+
   * The default value is `off`.
 
-## Syntax
+## The Ivo language
+### Syntax
 The parser's error messages currently are virtually useless, so be very careful with your syntax.
 
 * Variable names: any sequence of letters.
@@ -55,7 +81,7 @@ allow declarations (`let(rec) x = E` without multiple definitions `in ...`),
 which make your definitions available for the rest of the program's execution.
 You must separate your declarations and expressions with `;`.
 
-## Types
+### Types
 Types are checked/inferred using the Hindley-Milner type inference algorithm.
 
 * Functions: `a -> b` (constructed by `\x. e`)
@@ -68,18 +94,19 @@ Types are checked/inferred using the Hindley-Milner type inference algorithm.
 * Characters: `Char` (constructed by `Char`, which takes a `Nat`)
 * Universal quantification (forall): `∀a b. t`
 
-## Builtins
+### Builtins
 Builtins are variables that correspond with a built-in language feature
 that cannot be replicated by user-written code.
 They still are just variables though; they do not receive special syntactic treatment.
 
-* `callcc : ∀a b. (((a -> b) -> a) -> a)`: [the call-with-current-continuation control flow operator](https://en.wikipedia.org/wiki/Call-with-current-continuation).
+* `callcc : ∀a b. (((a -> b) -> a) -> a)`:
+  [the call-with-current-continuation control flow operator](https://en.wikipedia.org/wiki/Call-with-current-continuation).
 
 Continuations are printed as `λ!. ... ! ...`, like a lambda abstraction
 with an argument named `!` which is used exactly once;
 however, continuations are *not* the same as lambda abstractions
 because they perform the side effect of modifying the current continuation,
-and this is *not* valid syntax you can input into the REPL.
+and this is *not* valid syntax you can enter into the REPL.
 
-## Example code
+### Example code
-You can see some example code in `examples.lc`.
+You can see some example code in `examples/examples.ivo`.

app/Main.hs

@@ -1,6 +1,6 @@
 module Main (main) where
 
-import LambdaCalculus
+import Ivo
 
 import Control.Exception (IOException, catch)
 import Data.Maybe (isJust)

package.yaml

@@ -1,13 +1,13 @@
-name:                jtm-lambda-calculus
+name:                ivo
 version:             0.1.0.0
-github:              "jamestmartin/lambda-calculus"
+github:              "ivolang/ivo"
 license:             GPL-3
 author:              "James Martin"
 maintainer:          "james@jtmar.me"
-copyright:           "2019-2020 James Martin"
+copyright:           "2019-2021 James Martin"
-synopsis:            "A simple implementation of the lambda calculus."
+synopsis:            "A useless programming language for useless people."
-category:            LambdaCalculus
+category:            Language
-description:         Please see the README on GitHub at <https://github.com/jamestmartin/lambda-calculus#readme>
+description:         Please see the README on GitHub at <https://github.com/ivolang/ivo#readme>
 
 extra-source-files:
 - README.md
@@ -63,7 +63,7 @@ library:
   - -Wno-missing-import-lists
 
 executables:
-  jtm-lambda-calculus:
+  ivo:
     main:                Main.hs
     source-dirs:         app
     ghc-options:
@@ -75,12 +75,12 @@ executables:
     - -Wno-monomorphism-restriction
     - -Wno-unused-do-bind
     dependencies:
-    - jtm-lambda-calculus
+    - ivo
     - exceptions >= 0.10.4 && < 0.11
     - haskeline >= 0.8 && < 1
 
 tests:
-  jtm-lambda-calculus-test:
+  ivo-test:
     main: Spec.hs
     source-dirs: test
     ghc-options:
@@ -89,6 +89,6 @@ tests:
     - -rtsopts
     - -with-rtsopts=-N
     dependencies:
-    - jtm-lambda-calculus
+    - ivo
     - tasty >= 1.2 && < 2
     - tasty-hunit >= 0.10 && < 0.11

src/Ivo.hs

@@ -1,15 +1,15 @@
-module LambdaCalculus
+module Ivo
-  ( module LambdaCalculus.Evaluator
+  ( module Ivo.Evaluator
-  , module LambdaCalculus.Expression
+  , module Ivo.Expression
-  , module LambdaCalculus.Syntax
+  , module Ivo.Syntax
-  , module LambdaCalculus.Types
+  , module Ivo.Types
   , parseCheck, parseEval, unparseCheck, unparseEval
   ) where
 
-import LambdaCalculus.Evaluator
+import Ivo.Evaluator
-import LambdaCalculus.Expression
+import Ivo.Expression
-import LambdaCalculus.Syntax
+import Ivo.Syntax
-import LambdaCalculus.Types
+import Ivo.Types
 
 parseCheck :: Text -> Either ParseError CheckExpr
 parseCheck = fmap ast2check . parseAST

src/Ivo/Evaluator.hs

@@ -1,4 +1,4 @@
-module LambdaCalculus.Evaluator
+module Ivo.Evaluator
   ( Expr (..), Ctr (..), Pat, ExprF (..), PatF (..), VoidF, UnitF (..), Text
   , Eval, EvalExpr, EvalX, EvalXF (..)
   , pattern AppFE, pattern CtrE, pattern CtrFE
@@ -6,8 +6,8 @@ module LambdaCalculus.Evaluator
   , eval, evalTrace, evalTraceGlobal
   ) where
 
-import LambdaCalculus.Evaluator.Base
+import Ivo.Evaluator.Base
-import LambdaCalculus.Evaluator.Continuation
+import Ivo.Evaluator.Continuation
 
 import Control.Monad.Except (MonadError, ExceptT, throwError, runExceptT)
 import Control.Monad.Loops (iterateM_)

src/Ivo/Evaluator/Base.hs

@@ -1,4 +1,4 @@
-module LambdaCalculus.Evaluator.Base
+module Ivo.Evaluator.Base
   ( Identity (..)
   , Expr (..), Ctr (..), Pat, ExprF (..), PatF (..), VoidF, UnitF (..), Text
   , substitute, substitute1, rename, rename1, free, bound, used
@@ -7,7 +7,7 @@ module LambdaCalculus.Evaluator.Base
   , pattern ContE, pattern ContFE, pattern CallCCE, pattern CallCCFE
   ) where
 
-import LambdaCalculus.Expression.Base
+import Ivo.Expression.Base
 
 import Control.Monad (forM)
 import Control.Monad.Reader (asks)

src/Ivo/Evaluator/Continuation.hs

@@ -1,9 +1,9 @@
-module LambdaCalculus.Evaluator.Continuation
+module Ivo.Evaluator.Continuation
   ( Continuation, continue, continue1
   , ContinuationCrumb (..)
   ) where
 
-import LambdaCalculus.Evaluator.Base
+import Ivo.Evaluator.Base
 
 import Data.List (foldl')
 

src/Ivo/Expression.hs

@@ -1,4 +1,4 @@
-module LambdaCalculus.Expression
+module Ivo.Expression
   ( Expr (..), Ctr (..), Pat, ExprF (..), PatF (..), DefF (..), VoidF, UnitF (..), Text
   , substitute, substitute1, rename, free, bound, used
   , Eval, EvalExpr, EvalX, EvalXF (..), Identity (..)
@@ -15,9 +15,9 @@ module LambdaCalculus.Expression
   , builtins
   ) where
 
-import LambdaCalculus.Evaluator.Base
+import Ivo.Evaluator.Base
-import LambdaCalculus.Syntax.Base
+import Ivo.Syntax.Base
-import LambdaCalculus.Types.Base
+import Ivo.Types.Base
 
 import Data.Functor.Foldable (cata, hoist)
 import Data.HashMap.Strict (HashMap)

src/Ivo/Expression/Base.hs

@@ -1,6 +1,6 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE UndecidableInstances #-}
-module LambdaCalculus.Expression.Base
+module Ivo.Expression.Base
   ( Text, VoidF, UnitF (..), absurd'
   , Expr (..), Ctr (..), Pat, Def, AppArgs, AbsArgs, LetArgs, CtrArgs, XExpr
   , ExprF (..), PatF (..), DefF (..), AppArgsF, LetArgsF, CtrArgsF, XExprF

src/Ivo/Syntax.hs

@@ -0,0 +1,7 @@
+module Ivo.Syntax
+  ( module Ivo.Syntax.Parser
+  , module Ivo.Syntax.Printer
+  ) where
+
+import Ivo.Syntax.Parser
+import Ivo.Syntax.Printer

src/Ivo/Syntax/Base.hs

@@ -1,4 +1,4 @@
-module LambdaCalculus.Syntax.Base
+module Ivo.Syntax.Base
   ( Expr (..), ExprF (..), Ctr (..), Pat, Def, DefF (..), PatF (..), VoidF, Text, NonEmpty (..)
   , substitute, substitute1, rename, rename1, free, bound, used
   , Parse, AST, ASTF, ASTX, ASTXF (..), NonEmptyDefFs (..)
@@ -8,7 +8,7 @@ module LambdaCalculus.Syntax.Base
   , simplify
   ) where
 
-import LambdaCalculus.Expression.Base
+import Ivo.Expression.Base
 
 import Data.Functor.Foldable (embed, project)
 import Data.List.NonEmpty (NonEmpty (..), toList)

src/Ivo/Syntax/Parser.hs

@@ -1,11 +1,11 @@
-module LambdaCalculus.Syntax.Parser
+module Ivo.Syntax.Parser
   ( ParseError, parse
   , DeclOrExprAST, ProgramAST
   , parseAST, parseDeclOrExpr, parseProgram
   , astParser, declOrExprParser, programParser
   ) where
 
-import LambdaCalculus.Syntax.Base
+import Ivo.Syntax.Base
 
 import Data.List.NonEmpty (fromList)
 import Data.Text qualified as T

src/Ivo/Syntax/Printer.hs

@@ -1,6 +1,6 @@
-module LambdaCalculus.Syntax.Printer (unparseAST) where
+module Ivo.Syntax.Printer (unparseAST) where
 
-import LambdaCalculus.Syntax.Base
+import Ivo.Syntax.Base
 
 import Data.Functor.Base (NonEmptyF (NonEmptyF))
 import Data.Functor.Foldable (cata)

src/Ivo/Types.hs

@@ -1,9 +1,9 @@
-module LambdaCalculus.Types
+module Ivo.Types
-  ( module LambdaCalculus.Types.Base
+  ( module Ivo.Types.Base
   , infer
   ) where
 
-import LambdaCalculus.Types.Base
+import Ivo.Types.Base
 
 import Control.Applicative ((<|>))
 import Control.Monad (when)

src/Ivo/Types/Base.hs

@@ -1,5 +1,5 @@
 {-# LANGUAGE TemplateHaskell #-}
-module LambdaCalculus.Types.Base
+module Ivo.Types.Base
   ( Identity (..)
   , Expr (..), Ctr (..), Pat, ExprF (..), PatF (..), VoidF, UnitF (..), Text
   , substitute, substitute1, rename, rename1, free, bound, used
@@ -24,7 +24,7 @@ import Data.HashMap.Strict qualified as HM
 import Data.List (foldl1')
 import Data.Text qualified as T
 import Data.Traversable (for)
-import LambdaCalculus.Expression.Base
+import Ivo.Expression.Base
 
 data Check
 type CheckExpr = Expr Check

src/LambdaCalculus/Syntax.hs

@@ -1,7 +0,0 @@
-module LambdaCalculus.Syntax
-  ( module LambdaCalculus.Syntax.Parser
-  , module LambdaCalculus.Syntax.Printer
-  ) where
-
-import LambdaCalculus.Syntax.Parser
-import LambdaCalculus.Syntax.Printer

test/Spec.hs

@@ -1,4 +1,4 @@
-import LambdaCalculus
+import Ivo
 
 import Test.Tasty
 import Test.Tasty.HUnit