mirror of
https://github.com/janet-lang/janet
synced 2024-12-02 21:09:55 +00:00
79 lines
1.9 KiB
Plaintext
79 lines
1.9 KiB
Plaintext
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# This file is executed without any macro expansion (macros are not
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# yet defined). Cannot use macros or anything outside the stl.
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# Helper for macro expansion
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(def macroexpander (fn [x env f]
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(if (= (type x) :tuple)
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(if (> (length x) 0)
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(do
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(def first (get x 0))
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(def macros (get env :macros))
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(if macros
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(do
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(def macro (get macros first))
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(if macro
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(f (apply macro (slice x 1)))
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x))
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x)
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x)
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x)
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x)))
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# Macro expansion
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(def macroexpand (fn [x env]
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(macroexpander x (if env env (getenv)) macroexpander)))
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# Function to create macros
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(def global-macro (fn [name f]
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(def env (getenv))
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(def env-macros (get env :macros))
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(def macros (if env-macros env-macros {}))
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(set! env :macros macros)
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(set! macros (symbol name) f)
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f))
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# Make defn
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(global-macro "defn" (fn [name &]
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(tuple 'def name (apply tuple 'fn &))))
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# Make defmacro
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(global-macro "defmacro" (fn [name &]
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(tuple global-macro (string name) (apply tuple 'fn &))))
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# Comment returns nil
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(global-macro "comment" (fn [] nil))
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# The source file to read from
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(var *sourcefile* stdin)
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# The *read* macro gets the next form from the source file, and
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# returns it. It is a var and therefor can be overwritten.
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(var *read* (fn []
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(def b (buffer))
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(def p (parser))
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(while (not (parse-hasvalue p))
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(read *sourcefile* 1 b)
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(if (= (length b) 0)
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(error "parse error: unexpected end of source"))
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(parse-charseq p b)
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(if (= (parse-status p) :error)
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(error (string "parse error: " (parse-consume p))))
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(clear b))
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(parse-consume p)))
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# Evaluates a form by macro-expanding it, compiling it, and
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# then executing it.
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(def eval (fn [x]
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(def func (compile (macroexpand x)))
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(if (= :function (type func))
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(func)
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(error (string "compiler error: " func)))))
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# A simple repl for testing.
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(while true
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(def t (thread (fn []
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(while true
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(print (eval (*read*)))))))
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(print (tran t)))
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