Problem 44382. Parse me a Lisp

Created by @bmtran (Bryant Tran)

Solve Later

Description

In Lisp and its variants, function calls are done using parenthesis where the first item in the parenthesis is the function being called and the following items are arguments to the function. Given a mathematical ( + - * / ) expression using this notation, return the result. Note: In Lisp, functions that normally take only two arguments can be called with many arguments, with the function being applied to all elements from left to right.

Simple example

(+ 1 1 1 1 1)

would give 5.

Complicated example

(* (* 10 (+ 1 4)) (+ 10 (/ 12 2 3) 1) 0.1)

would give 65.

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Last Solution submitted on Jan 24, 2023

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3 Comments

Alfonso Nieto-Castanon on 19 Oct 2017

it seems look-up table solutions are becoming a bit of an issue, could you please add a few test cases to discourage this? +1 for random test cases that are a bit harder to trick, for example something like n=randi(100,1,randi(10)); expr = "(+" + string(num2str(n))+ ")"; assert(isequal(eval_lisp(expr), sum(n)));

James on 11 Dec 2017

I think another test case with multiple expressions would be equally useful. Even something as simple as (+ 1 (* 2 3) 4) would prevent some of the look-up solutions. Make some of those values random, and it will work even better.

Rafael S.T. Vieira on 8 Jul 2020

Good problem, and better than 44374. Precedence is clear.

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Problem 44382. Parse me a Lisp

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Problem 44382. Parse me a Lisp

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Last 200 Solutions

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