GNU / sed Lisp Interpreter
Interpreter Lisp on python in one line ? Too boring.
Japanese programmer, Google engineer Shinichiro Hamaji wrote it on sed. Sed is a streaming text editor, which is a simple programming language. There are no variables in it; there is only a GOTO primitive and branching functionality; nevertheless, it is Turing complete.
Implementation takes only 600 lines.
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It looks like this:
Repository on Github
Japanese programmer, Google engineer Shinichiro Hamaji wrote it on sed. Sed is a streaming text editor, which is a simple programming language. There are no variables in it; there is only a GOTO primitive and branching functionality; nevertheless, it is Turing complete.
Implementation takes only 600 lines.
')
It looks like this:
Usage example
$ sed -f sedlisp.sed # '>' > (car (quote (abc))) a > (cdr (quote (abc))) (bc) > (cons 1 (cons 2 (cons 3 ()))) (1 2 3) > (defun fact (n) (if (eq n 0) 1 (* n (fact (- n 1))))) (lambda (n) (if (eq n 0) 1 (* n (fact (- n 1))))) > (fact 10) 3628800 > (defun fib (n) (if (eq n 1) 1 (if (eq n 0) 1 (+ (fib (- n 1)) (fib (- n 2)))))) (lambda (n) (if (eq n 1) 1 (if (eq n 0) 1 (+ (fib (- n 1)) (fib (- n 2)))))) > (fib 12) 233 > (defun gen (n) ((lambda (xy) y) (define G n) (lambda (m) (define G (+ G m))))) (lambda (n) ((lambda (xy) y) (define G n) (lambda (m) (define G (+ G m))))) > (define x (gen 100)) (lambda (m) (define G (+ G m))) > (x 10) 110 > (x 90) 200 > (x 300) 500 Repository on Github
Source: https://habr.com/ru/post/227983/
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