Build My Own Lisp

Learning C and building my own programming language with the book “Build Your Own Lisp”.

Building

Just run:

make

Running

After building type:

./lispy

Examples

Arithmetic operations:

lispy> + (* 2 (- 1 3) (/ 4 2)) 
-8

List functions:

lispy> eval (head (tail (join {1 2} (list 3 4 5))))
2

Variable functions:

lispy> def {x z} 123 -321
()
lispy> x
123
lispy> y
-321
lispy> = {x} 1
()
lispy> x
1

Lambda functions:

lispy> \ {x y} {+ x y}
(\ {x y} {+ x y})

Functions defenition:

lispy> fun {curry f xs} {eval (join (list f) xs)}
()
lispy> curry + {5 6 7}
18

Comparison operations:

lispy> > 3 1
1

Logical operators:

lispy> def {x y z} 1 2 3
()
lispy> if (or (== x y) (>= z y)) {+ x y} {- x y}
3

Get local environment:

lispy> locals {}
{{+ <builtin>} {- <builtin>} {* <builtin>} {/ <builtin>}
 {> <builtin>} {>= <builtin>} {< <builtin>} {<= <builtin>}
 {== <builtin>} {!= <builtin>} {if <builtin>} {or <builtin>} 
 {and <builtin>} {not <builtin>} {list <builtin>} {head <builtin>}
 {tail <builtin>} {eval <builtin>} {join <builtin>} {def <builtin>}
 {\ <builtin>} {fun <builtin>} {= <builtin>} {locals <builtin>}
 {exit <builtin>}}

Strings, comments and file execution

./lispy hello.lspy
"Hello World!"

or

lispy> load "hello.lspy"
"Hello World!" 
()

Standard library functions:

lispy> map (\ {x} {+ x 10}) {5 2 11}
{15 12 21}
lispy> filter (\ {x} {> x 2}) {5 2 11 -7 8 1}
{5 11 8}

Exit function (or use Ctrl+C):

lispy> exit {}

Progress

• [X] Chapter 1 • Introduction
• [X] Chapter 2 • Installation
• [X] Chapter 3 • Basics
• [X] Chapter 4 • An Interactive Prompt
• [X] Chapter 5 • Languages
• [X] Chapter 6 • Parsing
• [X] Chapter 7 • Evaluation
• [X] Chapter 8 • Error Handling
• [X] Chapter 9 • S-Expressions
• [X] Chapter 10 • Q-Expressions
• [X] Chapter 11 • Variables
• [X] Chapter 12 • Functions
• [X] Chapter 13 • Conditionals
• [X] Chapter 14 • Strings
• [X] Chapter 15 • Standard Library
• [X] Chapter 16 • Bonus Projects
• 🚀 Work on improvements and new features…