| 1 | [[tags: manual]] |
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| 2 | |
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| 3 | == Deviations from the standard |
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| 4 | |
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| 5 | Identifiers are by default case-sensitive (see |
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| 6 | [[http://galinha.ucpel.tche.br:8080/Using%20the%20compiler#Compiler%20command%20line%20format|Compiler command line format]]). |
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| 7 | |
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| 8 | [4.1.3] The maximal number of arguments that may be passed to a |
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| 9 | compiled procedure or macro is 120. A macro-definition that has a |
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| 10 | single rest-parameter can have any number of arguments. |
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| 11 | |
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| 12 | [4.2.2] {{letrec}} does evaluate the initial values for the bound |
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| 13 | variables sequentially and not in parallel, that is: |
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| 14 | |
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| 15 | (letrec ((x 1) (y 2)) (cons x y)) |
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| 16 | |
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| 17 | is equivalent to |
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| 18 | |
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| 19 | (let ((x (void)) (y (void))) |
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| 20 | (set! x 1) |
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| 21 | (set! y 2) |
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| 22 | (cons x y) ) |
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| 23 | |
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| 24 | where R5RS requires |
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| 25 | |
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| 26 | (let ((x (void)) (y (void))) |
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| 27 | (let ((tmp1 1) (tmp2 2)) |
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| 28 | (set! x tmp1) |
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| 29 | (set! y tmp2) |
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| 30 | (cons x y) ) ) |
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| 31 | |
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| 32 | [6.1] {{equal?}} compares all structured data recursively, while R5RS |
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| 33 | specifies that {{eqv?}} is used for data other than pairs, strings and |
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| 34 | vectors. |
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| 35 | |
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| 36 | [6.2.4] The runtime system uses the numerical string-conversion |
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| 37 | routines of the underlying C library and so does only understand |
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| 38 | standard (C-library) syntax for floating-point constants. |
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| 39 | |
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| 40 | [6.2.5] There is no built-in support for rationals, complex numbers or |
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| 41 | extended-precision integers (bignums). The routines {{complex?}}, |
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| 42 | {{real?}} and {{rational?}} are identical to the standard procedure |
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| 43 | {{number?}}. The procedures {{numerator}}, {{denominator}}, |
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| 44 | {{rationalize}}, {{make-rectangular}} and {{make-polar}} are not |
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| 45 | implemented. Fixnums are limited to ±2<nowiki><sup>30</sup></nowiki> |
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| 46 | (or ±2<nowiki><sup>62</sup></nowiki> on 64-bit hardware). Support for |
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| 47 | extended numbers is available as a separate package, provided the GNU |
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| 48 | multiprecision library is installed. |
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| 49 | |
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| 50 | [6.2.6] The procedure {{string->number}} does not obey read/write |
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| 51 | invariance on inexact numbers. |
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| 52 | |
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| 53 | [6.4] The maximum number of values that can be passed to continuations |
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| 54 | captured using {{call-with-current-continuation}} is 120. |
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| 55 | |
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| 56 | [6.5] Code evaluated in {{scheme-report-environment}} or |
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| 57 | {{null-environment}} still sees non-standard syntax. |
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| 58 | |
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| 59 | [6.6.2] The procedure {{char-ready?}} always returns {{#t}} for |
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| 60 | terminal ports. The procedure {{read}} does not obey read/write |
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| 61 | invariance on inexact numbers. |
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| 62 | |
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| 63 | [6.6.3] The procedures {{write}} and {{display}} do not obey |
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| 64 | read/write invariance to inexact numbers. |
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| 65 | |
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| 66 | [6.6.4] The {{transcript-on}} and {{transcript-off}} procedures are |
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| 67 | not implemented. |
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| 68 | |
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| 69 | --- |
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| 70 | Previous: [[Supported language]] |
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| 71 | |
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| 72 | Next: [[Extensions to the standard]] |
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