Sigma Lisp

1
Sigma Lisp

• S?
• Sam DavisNick Alexander

2
What is Sigma Lisp?

• New dialect of Lisp
• Designed to be as expressive as possible

3
Project Overview Why Lisp?

• Lisp is a highly abstract language
• S-expressions
• Shared notation for code and data
• Macros
• Functions that return code
• Lexical Scope
• Easy insertion of values
• Dynamic Typing

4
Project Overview Why Sigma?

• Onions in the varnish
• Features that are products of history
• Language needs have changed
• Cross-platform applications
• OS interactions
• Revive the Lisp model

5
Project Overview Principles

• Assume a sufficiently smart programmer
• Expressive enough to use and redefine itself
• Time efficiency for the programmer
• Language first, implementation second
• I can't do everything myself
• Nothing is sacred

6
Project Overview Design

• Functional Programming
• Test individual components independent of state
• Bottom-up Design
• Build from independently coded components
• Link together powerful abstract tools

7
Components

• Basic Data Structs
• Parser
• Libraries
• Memory Management

• Sigma Structs
• Scopes
• Eval

8
Basic Data Structs

• Defines structures for basic manipulation and
  storage of data
• Array
• Hash
• Controls interaction through interface
• Foundation

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
Sigma Structs

• Sigma specific structures
• Object
• Scope
• Func
• Cons
• Num

13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
Parser

• Translates text input into Sigma object
  representing the S-expression
• Syntax
• quote '
• backtick
• comma ,

17
Eval

• Evaluates an object returned from Parser
• Symbol returns variable value
• List preforms a function application
• Everything else is returned
• ( a b) -gt application of function '' to values
  of 'a' and 'b'

18
Scopes

• System for variable management
• Stored in layers
• Maps string to value
• Represents the environment of variables

19
Libraries

• Native functions written in C
• Basic data manipulation
• Control structures
• Predefined functions in Sigma
• Higher level manipulation
• Derived functions and macros

20
Memory Management

• Hybrid reference counting and garbage collection
• Emphasis on reference counting
• Garbage collection acts as back up for circular
  structures

21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
Credits

• Nick
• Primary Coding Basic Structs, Sigma Structs,
  Debugging, Scope, Tests, Design Concepts
• Sam
• Eval, Parser, Debugging, Tests, Diagramming,
  Primary Research Paper Writer, Administrative
  Requirements