common lisp - using CLISP to make equations given a sequence of numbers -



common lisp - using CLISP to make equations given a sequence of numbers -

so have utilize clisp create 2 equaline equations given sequence of numbers

ie user enters 2 2 2 2:

2 + 2 = 2 + 2 ; valid

2 - 2 = 2 - 2 ; valid

2 = 2 + 2 - 2 ; valid

2 + 2 + 2 = 2 ; not valid

user enters 6 2 2 2:

6 = 2 + 2 + 2 ; valid

6 = 2 * 2 + 2 ; valid

6 + 2 = 2 * 2 ; not valid

the operates of *, /, +, , - used basic math, , = signify left hand side = right hand side.

my problem lies in lack of real lisp training , start. think have utilize macros, i'm not sure how utilize macros or how macros used this.

i know have define function such

(defun findequation (a b c d))

but there i'm lost

first step: create combinations of relevant symbols, restriction 1 = should present.

example input: (2 2 2 2), (+ - * / =)

example output: (2 + 2 + 2 = 2), (2 + 2 - 2 = 2), (2 - 2 - 2 = 2), …

second step: utilize shunting-yard algorithm transform infix list of alternating numbers , symbols tree.

example input: (2 + 2 = 2 - 2)

example output: (= (+ 2 2) (- 2 2))

then can evaluate see if true.

common-lisp

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