#lang plai-typed

(require "python-core-syntax.rkt")

#|

Here is a suggestion for how to implement shared runtime functionality -

write it as core expression forms and use python-lib to wrap your

desugared expressions in an environment that will contain useful

bindings. For example, this sample library binds `print` to a function

that calls the primitive `print`.

|#

(define-type-alias Lib (CExp -> CExp))

(define print-lambda

(CFunc (list 'to-print) (hash (list))

(CPrim1 'print (CId 'to-print))))

(define assert-true-lambda

(CFunc (list 'check-true) (hash (list))

(CIf (CId 'check-true) (CId 'True) (CRaise (CApp (CId 'Exception) (list (CStr "Assert failed")))))))

(define assert-false-lambda

(CFunc (list 'check-false) (hash (list))

(CIf (CId 'check-false) (CRaise (CApp (CId 'Exception) (list (CStr "Assert failed")))) (CId 'True))))

(define fail-lambda

(CFunc (list 'msg) (hash (list))

(CRaise (CId 'msg))))

(define-type LibBinding

[bindO (left : symbol) (right : CObject)]

[bindE (left : symbol) (right : CExp)])

(define python-library

(list (bindO 'True py-True)

(bindO 'False py-False)

(bindO 'None py-None)

(bindO 'NotImplemented py-NotImplemented)

(bindO 'Exception py-Exception)

(bindO 'NameError py-NameError)

(bindO 'BaseException py-BaseException)

(bindO 'TypeError py-TypeError)

(bindO 'UnboundLocalError py-UnboundLocalError)

(bindE 'print print-lambda)

(bindE '___assertTrue assert-true-lambda)

(bindE '___assertFalse assert-false-lambda)

; (bindE '___assertIn asset-in-lambda)

; (bindE '___assertNotIn assert-not-in-lambda)

; (bindE '___assertEqual asset-equal-lambda)

; (bindE '___assertNotEqual assert-not-equal-lambda)

; (bindE '___assertRaises assert-raises-lambda)

; (bindE '___assertIs assert-is-lambda)

(bindE '___fail fail-lambda)

))

(define (get-library [id : symbol] [lv : (listof LibBinding)])

(cond

[(empty? lv)

(error 'get-library "not found")]

[(symbol=? id (type-case LibBinding (first lv)

(bindO (l r) l)

(bindE (l r) l)))

(first lv)]

[else (get-library id (rest lv))]))

(define (get-library-names [lv : (listof LibBinding)]) : (listof symbol)

(cond

[(empty? lv) empty]

[else (cons (type-case LibBinding (first lv)

(bindO (l r) l)

(bindE (l r) l))

(get-library-names (rest lv)))]))

(define (python-lib expr)

(local [(define (python-lib/recur libs)

(cond [(empty? libs) expr]

[(cons? libs)

(type-case LibBinding (first libs)

[bindE (name value)

(CSeq (CSetExp name value)

(python-lib/recur (rest libs)))]

[bindO (name value)

(CSeq (CSetObj name value)

(python-lib/recur (rest libs)))])]))]

(python-lib/recur python-library)))