Operator (from racket/base) not known

Questions & Answers
1

Hi,

i'm writing a parser to evaluate super-scripted expression (not sure it is a good idea in real life but i like the display) used in exponentiation expressions, here is a working example :

Welcome to DrRacket, version 8.14 [cs].
Language: reader SRFI-105, with debugging; memory limit: 8192 MB.
SRFI-105 Curly Infix parser for Racket Scheme and R6RS by Damien MATTEI
(based on code from David A. Wheeler and Alan Manuel K. Gloria.)

Parsed curly infix code result = 

(module repl racket (provide (all-defined-out)) (require Scheme+))
Scheme+ v10.0 by Damien Mattei

> {3 ²}
9

the above expression is well transformed (with syntax transformers) in (** 3 2) but if i try : {3 ⁻²} which require to transform the above expression in : (** 3 (- 2))
(note: i could produce (** 3 -2) which would work but for prefix general expressions it is not always possible to work like this)
then with (** 3 (- 2)) i have this error:

$nfx$ op1 e1 : parsed-args=.#<syntax (** 3 (- 2))>
. ../superscript-parser.rkt:207:24: -: unbound identifier;
 also, no #%top syntax transformer is bound
  context...:
  other binding...:
  context at layer 1...: in: -

the offending line of code is this one:

(return (cons #'-
		      (state-0-syntax-analysis nxt)))

that would return what would became after syntax transforming (- 2)

Writing this post i find a solution :

(return (cons '-
		      (state-0-syntax-analysis nxt)))

which give the good result:

{3 ⁻²}
1/9

i post anyway the message because i'm curious of what solution to avoid the original error. I found a solution with (quote -) but i hoped to have one with (syntax -) working too.
Generally adding something like (require (for-syntax racket/base)) is enought to remove the error, but not in this case.

(define n 3)
{3 ²*⁽ⁿ⁻⁴⁾}
1/9

{3 ²·⁽ⁿ⁻⁴⁾}
1/9

Damien