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Ingy döt Net 2013-06-05 21:47:54 +00:00
parent 1f1ad49427
commit 6f050a029e
2496 changed files with 37609 additions and 3031 deletions
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4
Task/Arithmetic-evaluation/REXX/arithmetic-evaluation.rexx
View file

@ -15,7 +15,7 @@ j=0; do forever; j=j+1; if j>L then leave; _=substr(x,j,1); _2=getX()
z=z _ $; iterate
end
if _=='+' | _=="-" then do; p_=word(z,words(z)) /*last Z token*/
if p_=='(' then z=z 0 /handle unary ±*/
if p_=='(' then z=z 0 /*handle unary±*/
z=z _ $; iterate
end
lets=0; sigs=0; #=_
@ -27,7 +27,7 @@ j=0; do forever; j=j+1; if j>L then leave; _=substr(x,j,1); _2=getX()
end /*exp*/
if pos(_,nchars)==0 then leave
lets=lets+datatype(_,'M') /*keep track of # of exponents. */
#=# || translate(_,'EEEEE','eDdQq') /*keep buildingthe num.*/
#=# || translate(_,'EEEEE','eDdQq') /*keep building the num*/
end /*j*/
j=j-1
if \datatype(#,'N') then call serr 'invalid number: ' #

35
Task/Arithmetic-evaluation/Racket/arithmetic-evaluation.rkt Normal file
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@ -0,0 +1,35 @@
#lang racket
(require parser-tools/yacc parser-tools/lex
(prefix-in ~ parser-tools/lex-sre))
(define-tokens value-tokens (NUM))
(define-empty-tokens op-tokens (OPEN CLOSE + - * / EOF NEG))
(define lex
(lexer [(eof) 'EOF]
[whitespace (lex input-port)]
[(~or "+" "-" "*" "/") (string->symbol lexeme)]
["(" 'OPEN]
[")" 'CLOSE]
[(~: (~+ numeric) (~? #\. (~* numeric)))
(token-NUM (string->number lexeme))]))
(define parse
(parser [start E] [end EOF]
[tokens value-tokens op-tokens]
[error void]
[precs (left - +) (left * /) (left NEG)]
[grammar (E [(NUM) $1]
[(E + E) (+ $1 $3)]
[(E - E) (- $1 $3)]
[(E * E) (* $1 $3)]
[(E / E) (/ $1 $3)]
[(- E) (prec NEG) (- $2)]
[(OPEN E CLOSE) $2])]))
(define (calc str)
(define i (open-input-string str))
(displayln (parse (λ() (lex i)))))
(calc "(1 + 2 * 3) - (1+2)*-3")