/CHANGES/system-result-value

http://github.com/alimoeeny/arc · #! · 17 lines · 13 code · 4 blank · 0 comment · 0 complexity · 23892b18b1d6d27c2b25834d0f10b2f1 MD5 · raw file 

    

  1. In mzscheme, 'system returns #t if the command it ran failed and #f otherwise.
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  2. This hack makes that information available in arc; 'system returns t on success
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  3. and nil on failure. In vanilla arc, 'system always returns nil.
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    5. 

  5. In vanilla arc:
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  6. 

  7.     arc> (system "false")
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  8.     nil
    9. 

  9.     arc> (system "true")
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  10.     nil
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  11. 

  12. With this hack:
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  13. 

  14.     arc> (system "false")
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  15.     nil
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  16.     arc> (system "true")
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  17.     t
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