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beautiful-racket/beautiful-racket-ragg/br/ragg/test/exercise-python-grammar.rkt

137 lines
5.8 KiB
Racket

9 years ago
#lang racket
(require br/ragg/examples/python-grammar
br/ragg/support
python-tokenizer
racket/generator
parser-tools/lex
racket/match
rackunit)
(define (kludge-nl-dedent-endmarker toks)
;; Kludge! If the last three tokens in the stream are:
;; NL, DEDENT, ENDMARKER,
;; then switch them around to:
;; DEDENT, NEWLINE, ENDMARKER
;; The Python tokenizer is doing something funny here, and I think
;; it's a bug in tokenize.py (and, transitively, the python-tokenizer
;; PLaneT package).
(cond [(< (length toks) 3)
toks]
[else
(define last-three-toks (take-right toks 3))
(match last-three-toks
[(list (list 'NL nl-text start-loc end-loc rest-str)
(and t2 (list 'DEDENT _ ...))
(and t3 (list 'ENDMARKER _ ...)))
(append (drop-right toks 3)
(list t2
(list 'NEWLINE nl-text start-loc end-loc rest-str)
t3))]
[else
toks])]))
(define (adapt-python-tokenizer ip #:end-marker-to-eof? [end-marker-to-eof? #f])
(define generated-tokens (kludge-nl-dedent-endmarker
(sequence->list (generate-tokens ip))))
(define tokens (sequence->generator generated-tokens))
(lambda ()
(let loop ()
(define next-token (tokens))
(match next-token
[(list type text (list start-line start-col) (list end-line end-col) rest-string)
;; FIXME: improve the Python tokenizer to hold offsets too.
(define start-pos (position #f start-line start-col))
(define end-pos (position #f end-line end-col))
(cond
[(eq? type 'NL)
;; Skip over NL tokens: they are meant to represent the continuation
;; of a logical line.
(loop)]
[else
(position-token (case type
[(NAME)
(cond [(set-member? all-token-types (string->symbol text))
(token (string->symbol text) text)]
[else
(token 'NAME text)])]
[(OP)
(token (string->symbol text) text)]
[(NUMBER)
(token 'NUMBER text)]
[(STRING)
(token 'STRING text)]
[(COMMENT)
(token 'WHITESPACE #:skip? #t)]
[(NEWLINE)
(token 'NEWLINE text)]
[(DEDENT)
(token 'DEDENT text)]
[(INDENT)
(token 'INDENT text)]
[(ERRORTOKEN)
(error 'uh-oh)]
[(ENDMARKER)
(if end-marker-to-eof?
(token eof)
(token 'ENDMARKER text))])
start-pos
end-pos)])]
[(? void)
(token eof)]))))
(define sample-tokens (adapt-python-tokenizer
(open-input-string #<<EOF
import blah
def hello(x):
print "hello", repr(x)
blah.baz()
EOF
)))
(void #;pretty-write
(syntax->datum (parse "hello.py" sample-tokens)))
(define parse-expr (make-rule-parser expr))
(check-equal?
(syntax->datum (parse-expr
(adapt-python-tokenizer (open-input-string "42")
#:end-marker-to-eof? #t)))
'(expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "42"))))))))))
(check-equal?
(syntax->datum (parse-expr
(adapt-python-tokenizer (open-input-string "(lambda x,y: y,x)")
#:end-marker-to-eof? #t)))
'(expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "(" (testlist_comp (test (lambdef "lambda" (varargslist (fpdef "x") "," (fpdef "y")) ":" (test (or_test (and_test (not_test (comparison (expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "y")))))))))))))))) "," (test (or_test (and_test (not_test (comparison (expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "x"))))))))))))))) ")"))))))))))
(check-equal?
(syntax->datum (parse-expr
(adapt-python-tokenizer (open-input-string "sqrt(x^2+y^2)")
#:end-marker-to-eof? #t)))
'(expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "sqrt") (trailer "(" (arglist (argument (test (or_test (and_test (not_test (comparison (expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "x"))))))) "^" (and_expr (shift_expr (arith_expr (term (factor (power (atom "2")))) "+" (term (factor (power (atom "y"))))))) "^" (and_expr (shift_expr (arith_expr (term (factor (power (atom "2")))))))))))))))) ")"))))))))))
(define parse-single-input (make-rule-parser single_input))
(check-equal?
(syntax->datum
(parse-single-input
(adapt-python-tokenizer (open-input-string "def f(x):\n return x*x\n\n")
#:end-marker-to-eof? #t)))
'(single_input
(compound_stmt
(funcdef "def" "f" (parameters "(" (varargslist (fpdef "x")) ")") ":" (suite "\n" " " (stmt (simple_stmt (small_stmt (flow_stmt (return_stmt "return" (testlist (test (or_test (and_test (not_test (comparison (expr (xor_expr (and_expr (shift_expr (arith_expr (term (factor (power (atom "x"))) "*" (factor (power (atom "x")))))))))))))))))) "\n")) ""))) "\n"))