I have long been trying to find the error, I'm doing a programming language and have the next code, using ragg, I have a syntax-object(resto ...) what has a bracket as data, I transform this syntax-object to a datum:
(let ([i (syntax->datum #'(resto ...))])
(display "Content i:")
(display i)
(if (eq? i (string->symbol "(})"))
(display "true")
(display "false")
)
)
and the output is:
Content: (})
false
But if I do this
(for ([i (syntax->datum #'(resto ...))])
(displayln "Content:")
(displayln i)
(if (eq? i (string->symbol "}"))
(display "true")
(display "false")
)
)
and the output is:
Content: }
true
MY QUESTION: ¿WHY THE IF OF CLAUSE LET IS FALSE? ¿AS I CAN COMPARE THESE TWO TYPES AND THAT THE RESULT IS TRUE WITHOUT THE FOR?
Documentation about functions:
Each piece of code is doing a very different thing, I'll show you how to make each one work. The first one uses let to assign into a variable the whole list returned by syntax->datum, and afterwards you compare it against another list (better use equal? for testing equality, it's more general):
(let ([i (syntax->datum #'(|}|))]) ; `i` contains `(})`
(display "Content i: ")
(displayln i)
(if (equal? i '(|}|)) ; a list with a single element, the symbol `}`
(displayln "true")
(displayln "false")))
The second piece of code is using for to iterate over each element in a list, until it finds the symbol }:
(for ([i (syntax->datum #'(|}|))]) ; `i` contains `}`
(display "Content i: ")
(displayln i)
(if (equal? i '|}|) ; the symbol `}`
(displayln "true")
(displayln "false")))
As a side note, you have to be very careful with the way you're going to process all those curly brackets {} in your language, they're interpreted as normal parentheses () in Racket and they'll be tricky to handle, notice how I had to escape them by surrounding them with vertical bars.