Morganey

Lambda Calculus based, interpreted programming language that recognizes Church encoded structures.

Usage

Before doing anything useful with Morganey you need to install sbt first.

Samples

For language samples and examples please visit docs/samples/ directory. To execute a sample run:

$ sbt "run <path-to-sample>"

from the root of the source code directory. For example, to execute the 15 first fibonacci numbers sample run:

$ sbt "run docs/samples/fib.mgn"

For more information on executing Morganey programs please see Program Execution section.

REPL

To run the REPL just enter the following in the source code directory

$ sbt run

and start entring REPL commands there. You can enter

• <term> (see Language)
• <binding> (see Language)
• <loading> (see Language)
• :exit - exits the REPL
• :raw <term> - prints the representation of the term
• :unbind <regex> - clears either the current context, or all bindings matching the regex

The REPL will take the entered lambda term, beta-reduce it with the normal order reduction strategy and output the normal form of the entered lambda term.

To quit the REPL just ^C it.

Program Execution

To execute a program written in Morganey do the following:

$ sbt "run main.mgn"

Where main.mgn is the name of the file that contains the program. The program should provide an entry point. An entry point is a binding with the name main which is bound to function of one argument:

main := \input . ...

For more information see Execution Semantic

As a Thirdparty Dependency

Morganey is available on JCenter.

sbt

resolvers += Resolver.jcenterRepo

libraryDependencies ++= Seq(
  "me.rexim" %% "morganey" % "0.1.0"
)

Unit Tests

To run the Unit Tests enter the following in the source code directory

$ sbt clean coverage test
$ sbt coverageReport
$ sbt coverageAggregate

And after that you can take a look at the Unit Test coverage results. Just open target/scala-2.11/scoverage-report/index.html with your favorite browser.

Functional Tests

$ sbt funtests

Build an uberjar

To build an uberjar run the following command

$ sbt assembly

After that find the uberjar at target/scala-2.11/morganey.jar

Custom sbt commands

This project introduces the following custom sbt commands:

• sbt build: Compiles the subprojects kernel, macros and stdlib and copies the resulting JAR files into the target directory of the root project.

• sbt buildModuleIndex: Traverses the stdlib subproject and creates a resource file containing a list of modules - the so-called module-index. This command is run automatically if you sbt compile the project.

• sbt rebuild: Alias for the execution of the commands sbt clean and sbt build.

• sbt retest: Alias for the execution of the commands sbt rebuild and sbt test.

Language

BNF

<term> ::= <function>
         | <application>
         | <literal>
         | <variable>
         | "(" <term> "," <term> ")"
         | "(" <term> ")"
<binding> ::= "def" <variable> ":=" <term>
<loading> ::= "load" <module-path>
<module-path> := [a-zA-Z][a-zA-Z0-9.]*

<literal> ::= <numeric-literal>
            | <character-literal>
            | <string-literal>
            | <list-literal>
<numeric-literal> ::= [0-9]+
<character-literal> ::= '[\u0020-\u00B0]'
                      | '\\[\\'"bfnrt]'
<string-literal> ::= <java-string-literal>
<list-literal> ::= "[" [ term { "," term } ] "]"
                 | "[" <term> [ "," <term> ] ".." <term> "]"
<number-or-character> ::= <numeric-literal>
                        | <character-literal>

<variable> ::= [a-zA-Z][a-zA-Z0-9]*
<function> ::= <lambda-symbol> <variable> "." { <variable> "." } <term>
<application> ::= <term> <term> { <term> }
<lambda-symbol> ::= "λ"
                  | "\"

Comments

In Morganey there are two types of comments: single-line (starting with double slash //, extending to the end of the line) and multi-line comments (any text, surrounded by /* and */).

License

Copyright (C) 2015–2016 Codingteam

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.