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33 lines
1.3 KiB
Racket
33 lines
1.3 KiB
Racket
9 years ago
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#lang br
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(provide #%top-interaction) ; activates the REPL
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;; reader goes first and
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;; 1) converts surface syntax into Rackety expressions (wrapping in `(inst ...)`)
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;; 2) creates a module specifying semantics source (in this case, same module)
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(provide read-syntax)
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(define (read-syntax src-path src-input-port)
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(define expr-datums (for/list ([src-line (in-lines src-input-port)]
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#:when (regexp-match #px"\\w" src-line))
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(format-datum '~a src-line)))
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(syntax-let ([#'(expr-stx ...) expr-datums]) ; ok to bind with non-syntax
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#'(module stack-compiler-module "stack-compiler.rkt"
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expr-stx ...)))
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;; semantics always start with #%module-begin, which unwraps the content of the module and rewraps it
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(provide (rename-out [stack-module-begin #%module-begin]))
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(define #'(stack-module-begin expr ...)
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#'(#%module-begin
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(stackify (quote expr)) ...))
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(define (stackify quoted-expr)
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(define pushes
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(let loop ([x quoted-expr])
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(cond
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[(list? x)
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(match-define (list op args ...) x)
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(append (make-list (sub1 (length args)) op) (flatten (map loop args)))]
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[else x])))
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(for-each displayln (map (λ(p) (format "push ~a" p)) (reverse pushes))))
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