rhombus-prototype
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Unquoted matches are not available in the same pattern
Unquoted matches, that is, $ matches in a '' pattern, are not available within that pattern, even to later subpatterns. For example,
#lang rhombus/static
'1 2' is_a matching(
'$(first_int :: Int)
$(pattern:
kind ~term
| '$(second_int :: Int)':
match_when first_int.unwrap() == second_int.unwrap())'
)
this program does not work, nor does
#lang rhombus/static
syntax_class SomeInt(int):
kind ~term
| '$(this_int :: Int)':
match_when this_int.unwrap() == int
'1 2' is_a matching(
'$(first_int :: Int)
$(_ :: SomeInt(first_int.unwrap()))'
)
In contrast, the corresponding Racket program
#lang racket/base
(require syntax/parse)
(syntax-parse #'(1 2)
[(first-int:integer
(~and second-int:integer
(~fail #:unless (eqv? (syntax-e #'first-int)
(syntax-e #'second-int)))))
#t]
[_ #f])
works just fine.