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Questions tagged [dr.racket]

DrRacket is a graphical environment for developing programs using the Racket programming languages.

https://docs.racket-lang.org/drracket/

20 questions
34
votes
3 answers

Which lang packet is proper for SICP in Dr.Racket?

I'm trying with SICP and I got some code. So I started with: #lang scheme (word 'comp 'uter) Returned error: Function (word) undefined. Even if I tried to copy this into IDE(Run): (define word? (let ((number? number?) (symbol? symbol?) …
user2871676
17
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2 answers

Is there an autocomplete for Dr. Racket?

I usually use Sublime text editor and gnome terminal to edit and run my programs. Due to educational purposes, I am using the IDE Dr. Racket. I could not find an autocomplete feature to use while typing. I checked this out on google and at Dr.…
user4206400
3
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0 answers

How to recover a deleted racket file from DrRacket?

I recently (yesterday) finished up a somewhat large project that added up to almost 2300 lines of code. It was all in racket using the Dr.Racket IDE. I saved up the project, closed my laptop, and went on with my day. Later on, I opened my laptop,…
user3026388
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2
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1 answer

Sentence output is vertical with line breaks in-between each word

If a sentence of words is too long, the interpreter will print the sentence vertically with line breaks in-between each word, rather than with just one line break when the sentence reaches the edge of the buffer. > '(one two three four five six…
Asher
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2
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1 answer

show errors, creating a programming language in racket

I am creating a programming language in Racket, I am currently using ragg, I was reading the guide of Danny Yoo Guide Danny Yoo Ragg, I define a grammar, for example #lang ragg nested-word-list: WORD | LEFT-PAREN nested-word-list*…
Julian Solarte
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2
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1 answer

Racket 6.2 on Mac OS X 10.5.8

Can someone please tell me whether the pre-built binary of Racket 6.2 (including Dr.Racket) will work on OS X 10.5.8?
babon
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1 answer

output of Dr. Racket algebraic stepper to file

During debugging the stepper breaks down after reaching the bug. And stepping towards the bug every time takes at least a hundred clicks. So doing that every time seems senseless. Is there a way to save all the evaluation steps that you see in the…
X10D
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2 answers

calculate the sum of proper divisors of a given number in Racket BSL

Design a Racket function named findProperDivisor that takes a natural number and calculates the sum of all its proper divisors. A proper divisor of a natural number is the divisor that is strictly less than the number. Examples: Input: 20 Output:…
İrem Sözen
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1
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1 answer

Racket Error: Expected a procedure that can be applied to arguments

Sorry, I just started using racket. I'm pretty new at this. I've written this piece of code: (define (save_sheets lst num) (if(= num (- (length lst) 1)) ('()) ( (my_save_image (join_sheet (list-ref lst num)) num) (save_sheets…
JavaCafe01
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1
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1 answer

How to follow the Simply Scheme book with DrRacket

I'd like to be able to manipulate sentences so that I can take them as an input and return an output based on things like the individual letters. For example, an ends-e command that would return all of the words that end in "e": (ends-e '(only the…
Asher
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1
vote
1 answer

Racket function passing empty list instead of actual list

I'm pretty new to racket and I'm trying to make a finite state machine for a project. here's what I have so far. #lang racket (define (test rules cs pass lst) (if (eq? (length lst) 0) (if (member cs pass) (write 'passed) …
Arashi Nakamura
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0
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1 answer

(Racket) Trying to write a function that returns another function, but Racket says my lambda is not a function definition?

Programming in racket, I am trying to write a function that takes a single integer, and returns a function that increments that integer by another integer. So example ((incnth 5) 3) --> 8 ((incnth 3) -1) --> 2 Unfortunately I don't seem to…
BestInTOWN
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0
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1 answer

Dr Racket will not save any of my files. Has anyone had this error before or have any ideas?

I have reinstalled Dr Racket including older versions. No matter what whenever I save I get this error: There was an error saving bytes->string/locale: string is not a well-formed UTF-8 encoding string: #"pl\373"
Graham Mather
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0
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1 answer

What's setf and is it a valid function in Dr.Racket?

I have an assignment where I have to define an alias to an expression, in one of the guides we are told to use either setf or lists of lists to define them. To be more specific we need to assign to the alias ADD/SUCC/PRED/etc their lambda calculus…
Pamela Horn
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0
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0 answers

Is there a way to make a plain chart in DrRacket?

I've been looking for an answer online, but all I've found are ways to plot points and create graphs. I was inspired by this fitness tracker (https://www.reddit.com/r/Racket/comments/5ywuf8/my_hobby_project_in_racket_a_fitness_activity/) I'm trying…
user8503635
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