lisp_interpreter.py

# https://gist.github.com/dovinmu/bcab247b063cd3e294e57d06440268a1

def popParens(s):
    return s[s.find('(')+1:s.rfind(')')]

def getArgs(s):
    def appendArg(arg):
        if '(' in arg:
            args.append(getArgs(arg.strip()))
        else:
            try:
                number = float(arg.strip())
                if '.' in arg:
                    args.append(number)
                else:
                    args.append(int(number))
            except:
                args.append(arg.strip())

    s = popParens(s)
    args = []
    charIdx = 0
    parenDepth = 0
    inQuote = False
    for i in range(len(s)):
        if s[i] == '"':
            inQuote = not inQuote
        if inQuote:
            continue
        if s[i] == '(':
            parenDepth += 1
        elif s[i] == ')':
            parenDepth -= 1
        if parenDepth == 0:
            if s[i] == ' ' and s[charIdx:i].strip() != '':
                appendArg(s[charIdx:i])
                charIdx = i
    appendArg(s[charIdx:])
    return args

def testAST():
    s='(first (list 1 (+ 2 3) 9))'
    print(getArgs(s))
    s='(first "Hello World")'
    print(getArgs(s))
    s='(first (list "asdf fdsa" (+ 2 3) 9.2))'
    print(getArgs(s))
    s='''(defun factorial (n)
       (if (= n 0) 1
           (* n (factorial (- n 1)))))'''
    print(getArgs(s))
    s='''(defun -reverse (list)
      (let ((return-value '()))
        (dolist (e list) (push e return-value))
        return-value))'''
    print(getArgs(s))

if __name__ == "__main__":
    testAST()