# Where to find the correct syntax for #lang racklog?
**URL:** https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759
**Category:** Questions & Answers
**Created:** [May 24, 2025, 5:55pm UTC](https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759 "2025-05-24T17:55:18Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@UserX](https://racket.discourse.group/u/UserX)
#### Post date: [May 24, 2025, 5:55pm UTC](https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759/1 "2025-05-24T17:55:18Z")
It appears that either I'm doing something blatantly stupid or` #lang racklog` documentation misses some points.
Here the question.
According to the documentation
> This module language accepts the syntax of Datalog (except clauses need not be safe) and compiles each predicate to a relation.
> The accepted syntax is available in the [Datalog Module Language](https://docs.racket-lang.org/datalog/datalog.html) documentation.
Then, trying to run the example given in datalog, simply swapping "racklog" in place of "datalog"
```scheme
#lang racklog
(racket/base). % here the parenthesis are not required, correct is racket/base. I remove those but then...
fib(0, 0). % from here onward, numbers are not recognized
fib(1, 1).
fib(N, F) :- N != 1,
N != 0,
N1 :- -(N, 1),
N2 :- -(N, 2),
fib(N1, F1),
fib(N2, F2),
F :- +(F1, F2).
fib(30, F)?
```
Specifically, the message of error regarding the first number is
match-lambda: no matching clause for '#s(constant (14-unsaved-editor 6 4 39 1) 0)
The example works in #lang datalog (which should be a subset of #lang racklog)
---
### Author:  [@greghendershott](https://racket.discourse.group/u/greghendershott)
#### Post date: [May 25, 2025, 6:00pm UTC](https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759/2 "2025-05-25T18:00:40Z")
Although I'm not sure how actively the `racklog` package is maintained, it looks like its repo's issues page is [here](https://github.com/racket/racklog/issues), if you wanted to ask there.
---
### Author:  [@UserX](https://racket.discourse.group/u/UserX)
#### Post date: [May 26, 2025, 12:50am UTC](https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759/3 "2025-05-26T00:50:38Z")
Thanks, but I think that, yes, the problem is that the package is bugged, at least for the parser for the pure #lang racklog (maybe the module to use inside #lang racket works, instead).
Thanks for your time. 🙂
I wrote a comment on reddit, just now, I copy it here, to close the question.
> Eventually I think that simply the part of the code which should read the pure `#lang racklog` has been neglected and doesn't work.
>
> For example, going on I discovered that while
>
> > `fib(0, 0).`
>
> > `fib(1, 1).`
>
> gave errors, nstead this
>
> > `fib(+0, +0).`
>
> > `fib(+1, +1).`
>
> didn't.
>
> But then, again, for the rest of the code this trick doesn't work.
>
> Probably the mantainer was more interested to have it to work inside `#lang racket` and not as a language in itself (which after all makes sense, since Prolog is a thing).
---
### Author:  [@soegaard](https://racket.discourse.group/u/soegaard)
#### Post date: [May 26, 2025, 9:44am UTC](https://racket.discourse.group/t/where-to-find-the-correct-syntax-for-lang-racklog/3759/4 "2025-05-26T09:44:27Z")
The syntax is the same. The semantics are different.
The problem is that bindings from `racket/base` overrides what `racklog` expects.
This leads to the curious errors you see.
It may or may not have been an oversight.
The examples in the repo uses:
```scheme
#lang racket
(require racklog)
```
Having the imports this way, the racklog definitions override the ones from `#lang racket`.
See for example:
>
But if you want to use the Datalog syntax, make a helper file, say, "helper.rkt"
that only exports `+` and `-` from `racket/base` and import that.