Djinn (جن) are supernatural creatures in Arab folklore and Islamic teachings that occupy a parallel world to that of mankind.
Djinn is a concatenative, functional, stack-based programming language.
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Build the project
$ mvn package
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Run the REPL
$ java -jar target/djinn-1.0-SNAPSHOT-uber.jar
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Enjoy
$ java -jar target/djinn-1.0-SNAPSHOT-uber.jar
Welcome to Djinn.
Type ":quit" or ":exit" to end your session. Type ":help" for instructions.
User> "hello, world" println
hello, world
stack:
The REPL supports three forms of statements: declarations, functions and immediate statements.
To bind a name to the result of a lambda, use a declaration:
User> \name "Djinn"
=> <<Declaration>> "name" = ["Djinn"]
The name "name" is now bound to a lambda containing the string "Djinn". When this name is referenced, the lambda will be evaluated at that time. This is an example of the syntax sugar provided when you want to simply bind a single immediate value to a name. Immediate values can be integers, decimals or strings. Otherwise if you want to bind the result of a complete lambda to a name, do this:
User> \value [1 1 add]
=> <<Declaration>> "value" = [1 1 add]
To create a new function, do this:
User> \[increment 1 add]
=> <<Function>> "increment"
The syntax for functions takes the form of:
'\[' NAME (lambda '?')? atom+ function* declaration* ']'
The name of the function comes first, followed by an optional pattern lambda. This is a special lambda that will be executed before the body of the function to determine if the function should be activated. The pattern lambda definition MUST be suffixed by a question mark ('?') to be considered as the pattern.
In this way, multiple function definitions can be grouped together into a "method" sharing the same name, but different patterns and bodies. If a function is a member of a method family, then the members will be evaluated one-at-a-time to determine which one should be activated. If a member does not have a pattern defined and none of the pattern-bearing members were suitable then that default function will be activated.
For example, the definition for the method "ifel" (from the Djinn prelude):
\[ifel [id]? drop [drop] dip apply]
\[ifel drop drop apply]
Any terms entered into the REPL that are not defining declarations or functions will be executed immediately.
User> name
stack: "Djinn"
User> 5 increment
stack: "Djinn" 6
User> value
stack: "Djinn" 6 2
Copyright (c) 2011 Kevin Birch
Distributed under an MIT-style license.
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.